Yazarlar Stephen Steiner adlı onun ilham ve teknik anlayışlar Aerogel teknolojileri ve Dr Deryn Chu ordu araştırma laboratuvarı-sensörler ve elektron cihazları Müdürlüğü, Dr Christopher Haines, silah araştırma minnettarız, Geliştirme ve Mühendislik Merkezi, ABD Ordusu RDECOM-ARDEC ve Dr. Stephen Bartolucci onların yardım için ABD Ordusu Benet laboratuarlarında. Bu eser desteklenmiştir Amerika Birleşik Devletleri Askeri Akademisi, West Point bir öğretim kalkınma Araştırma Fonu Hibe tarafından.

Dikkat: tüm ilgili güvenlik bilgi formları (SDS) kullanmadan önce danışın. Uygun güvenlik uygulamaları kimyasal reaksiyonlar, bir duman hood ve kişisel koruyucu ekipman kullanımı dahil etmek için kullanırlar. Hızlı Hidrojen gaz evrim yüksek basınç pop için kapaklar neden tepki tüpler ve çözümleri sprey dışarı neden olabilir. Tepki tüp kapakları açık olarak belirtilen iletişim kuralı kalmadığından emin olun.
1. metal jel hazırlık
<ol><li>
Metal iyon çözümleri hazırlanması.
	<ol>
<li>2 mL 0.1 M çözümleri aşağıdaki tuzları, hazırlamak: HAuCl4•3H2O Na ve2PdCl4 deiyonize su. 2 mL 0.1 M K2PtCl6 bir 1:1 (v/v) su hazırlamak ve etanol çözücü. Tuz dağılmasına yardımcı olmak için şiddetle sallamak ve girdap çözümleri.</li>
	</ol>
</li>
	<li>
İndirgeyici çözüm hazırlanması.
	<ol>
<li>10 mL 0.1 M çözümleri aşağıdaki azalan bakiyeli ajanların hazırlamak: dimethylamine borane (DMAB) ve NaBH4 (sodyum borhidrür).</li>
	</ol>
</li>
	<li>
Au hazırlanması jelleri.
	<ol>
<li>0.5 mL 0.1 M HAuCl4•3H2O çözeltisi 1.7 mL veya 2.0 mL microcentrifuge tüp içine pipet. Zorla DMAB 0.5 mL tuz ve indirgeyici çözümleri hızlı bir karışımını sağlamak için altın çözüm ile microcentrifuge tüp içine pipet. Çözümler karışınca microcentrifuge tüp dikey olarak açık tüp kapaklı tüp raf yerleştirin. Not: Eğer tüp kapağı sol kapalı, Hidrojen gaz evrim içinde basınç kapağı açık pop zorlamak ve potansiyel olarak azaltma karışımı sprey için neden olur.</li>
	</ol>
</li>
	<li>
Pd hazırlanması jelleri.
	<ol>
<li>0.5 mL 0.1 M Na2PdCl4 çözeltisi 1.7 mL veya 2.0 mL microcentrifuge tüp içine pipet. Zorla NaBH4 0.5 mL Paladyum çözüm ile microcentrifuge tüp içine pipet. Yer microcentrifuge tüpü bir tüp raf tüp kapaklı dikey olarak açın.</li>
	</ol>
</li>
	<li>
Pt hazırlanması jelleri.
	<ol>
<li>0.5 mL 0.1 M K2PtCl6 çözüm 1.7 mL veya 2.0 mL microcentrifuge tüp içine pipet. Zorla DMAB 0.5 mL platin çözüm ile microcentrifuge tüp içine pipet. Yer microcentrifuge tüpü bir tüp raf tüp kapaklı dikey olarak açın.</li>
	</ol>
</li>
	<li>
Tüp inversiyon.
	<ol>
<li>Yaklaşık 5 dk microcentrifuge tüpleri kap ve için 3 - 5 kez yavaşça tersine çevirin yardım metal parçacıklar metal jel parçası değil birleştirme içinde. Emin olun tüp kapaklar hemen olan kapağını tüpler ters çevirme sonra ve Değiştir tüpleri bir rafa tüp dikey yönünü korumak için.</li>
	</ol>
</li>
	<li>
Denge.<ol>
<li>Otomatik Güncelleştirmeler, Pd ve Pt jelleri başlangıçta birkaç dakika içinde sahipken doğmakta olan jeller indirgeyici çözüm tam metal iyonları azalma ve gerçekleşmesi yüzey serbest enerji minimizasyonu için izin vermek 3-6 h için bırakın. Not: Metal jelleri karma metal iyon ve indirgeyici çözüm ilk hacmi daha küçük bir hacim kaplar. Bazı ek hafif cilt daralma denge dönemde gözlenen daha altın tırnaklar için jeller telaffuz ve25olgunlaşma Ostwald nedeniyle olduğuna inanılan.</li>
	</ol>
</li>
	<li>
Jel durulama.<ol>
<li>Otomatik Güncelleştirmeler, Pd ve Pt jelleri denge dönemi nden sonra için aşırı indirgeyici çözüm kaldırmayı ancak metal jel su altında kalması yeterli çözüm hacim bırakmak. Çözüm menisküs ile temas metal jel gelmez emin olun. Not: her ne kadar jelleri kılcal bir spatula ile çözüm arasında aktarmak için yeterince kararlı metal çözüm menisküs ile temas nedeniyle zorlar deforme ve son aerogel yoğunluk artışı sonuçlanan jelleri sıkıştırmak. Bu bazı indirgeyici çözüm ne zaman transfer deiyonize su batık jel ile tüp kalmasını gerektirir.</li>
		<li>Yavaş yavaş tepki microcentrifuge tüpler tepesine deiyonize su pipet. Bir 50 mL konik tüp deiyonize su dolu microcentrifuge tüpte daldırın ve jel microcentrifuge tüp dışarı slayt sağlar.</li>
		<li>Deiyonize su 24 h için jel bırakın ve 12 h su değiştirin. Jel ile temas gelmek sıvı bir menisküs izin vermemek için yapın.</li>
	</ol>
</li>
</ol>2. ıslak Metal jelleri karakterizasyonu elektrokimyasal yüzey alanı (ECSA)
Not: Elektrokimyasal karakterizasyonu donma kurutma iletken önce ıslak metal jelleri gerçekleştirilir. Elde edilen ECSA sonra son aerogel yapısı ve yüzey bir tahmindir. Azot adsorpsiyon ölçümleri kurutulmuş aerogels yüzey alanı tahmin etmek için kullanılır.
<ol><li>
Solvent Satım.<ol>
<li>Büyük bir kısmını Au deiyonize su kaldırmak için Pd ve Pt çözümler mümkün olduğunca durulama ve sıvı menisküs jel ile temas gelmediğinden emin olun.</li>
		<li>50 mL, 0,5 M KCl jel gözenekleri içinde elektrolit destekleyici deiyonize su alışverişi için konik tüpler için ekleyin. Jelleri KCl çözelti için 24 saat içinde bırakın.</li>
	</ol>
</li>
	<li>
Çalışma elektrodu hazırlanması.
	<ol>
<li>1 mm platin tel elektrot iyi bir fırça veya maruz tel ucu 4-5 mm uzunluğu bırakarak diğer kullanma aygıt kullanma non-reaktif cila ile kat.</li>
		<li>Kuru cila için 20 dakika izin verin.</li>
		<li>En az iki kat vernik uygulayın.</li>
	</ol>
</li>
	<li>
3-Elektrot Hücre set-up.
	<ol>
<li>3-Elektrot Hücre set-up bir Ag/AgCl ile (3 doymuş M) kullanmak referans elektrot, 0,5 mm çap Pt tel yardımcı/sayaç elektrot ve Lake boyalı çalışma elektrot.</li>
		<li>Bir plastik 50 mL konik tüp yarıya ve elektrokimyasal bir şişe kullanın.</li>
		<li>Jel çalışma elektrodu ile iki yöntemden biri ile başvurun: 1) Impaled jel veya 2) iletişim modu.<ol>
<li>
Elektrot - Impaled jel çalışma.<ol>
<li>Alt kısmındaki değiştirilmiş 50 mL konik tüp jel ile hafifçe cila kaplanmış elektrot jel yerleştirin. Not: Pd ve Pt elektrot ekleme daha sık üzerine kırık jelleri ise Impaled jel yöntemi Au jelleri ile daha etkili olmaktadır.</li>
			</ol>
</li>
			<li>
Çalışma elektrot - modu başvurun.<ol>
<li>Konik Boru iç yüzeyi boyunca Lake kaplamalı çalışma elektrot yerleştirin ve metal jel maruz Pt tel çalışma elektrot üstünde bekletin.</li>
			</ol>
</li>
		</ol>
</li>
	</ol>
</li>
	<li>
Elektrokimyasal empedans spektroskopisi (EIS).<ol>
<li>EIS frekansları 100 MHz ve 1 10 mV genlik sinüs dalga kullanarak mHz arasında inceden inceye gözden geçirmek potentiostatic gerçekleştirin. Geçerli taşmaları durumunda galvanostatic EIS aynı frekans aralığı ve 100-200 mA genlik sinüs dalga ile kullanın.</li>
	</ol>
</li>
	<li>
EIS verilerden elektrokimyasal yüzey alanı (ECSA) belirlenmesi.<ol>
<li>İçin Z ", empedans, en düşük fiyat EIS frekans f 1 mHz ve örnek kitle tarafından m, bölen sanal bileşeni belirli kapasitans, Cspbelirlemek için aşağıdaki denklemi kullanabilir: C SP = 1 / (2πfZ "m) (1) Not: Tüm çözümde metal iyonlarının jel oluşturmak için azaltılır varsayarak tarafından verilen bu ECSA adım 3'te aşağıdaki kurutma dondurmak için bir ıslak jel önceden belirlenir, kitle belirleyin. Bu duymadığını, herhangi bir gerçek verim az %100 Cspküçümseyen neden olur.</li>
	</ol>
</li>
	<li>
Çevrimsel voltammetry (CV).<ol>
<li>Tarama gore 100, 75, 50, 25, 10, 5 ve 1 mV/s CV ölçümleri için kullanın. Voltaj aralığı için 0,2 V-0.2 (vs Ag/AgCl) Au tırnaklar için jeller kullanın ve 0,1 için 0,4 V Pd ve Pt jelleri hidrojen adsorpsiyon ve desorpsiyon ve korunmada gereken indirgeme potansiyelini metal önlemek için seçin.</li>
	</ol>
</li>
	<li>
Elektrokimyasal yüzey alanı (ECSA) CV verilerden belirlenmesi.<ol>
<li>En yavaş CV tarama hızı 1 mV/s kullanın ve özel kapasite ile denklemi hesaplamak: C SP = (∫ivdv) / (2μmΔV) (2) Not: Burada ben ve v akım ve CV tarama (A ve V) potansiyel vardır, tarama oranıdır μ (V/s), jel kütlesi m (g) ise ΔV deşarj (vs Ag/AgCl) potansiyel pencere.</li>
	</ol>
</li>
</ol>3. Aerogel hazırlanması ve karakterizasyonu.
<ol><li>Adım 1.8 otomatik güncelleştirmeler, Pd ve Pt jelleri deiyonize suyla durulama su kaldırmak ve su menisküs metal jellerin ile temas halinde gelir değil emin olun.</li>
	<li>En az 30 dk Transfer için bir donma kurutma makinesi 4 set noktası basınçla donmuş metal jelleri-80 ° C dondurucuya jelleri yer Pa veya daha düşük.</li>
</ol>

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Computations from Nitrogen Isotherms.</a> Journal of the American Chemical Society. 73, 373-380 (1951).</li><li>Brunauer, B., Emmett, P., Teller, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adsorption+of+Gases+in+Multimolecular+Layers.">Adsorption of Gases in Multimolecular Layers.</a> Journal of the American Chemical Society. 60, 309-319 (1938).</li><li>Herrmann, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multimetallic+Aerogels+by+Template-Free+Self-Assembly+of+Au,+Ag,+Pt,+and+Pd+Nanoparticles.">Multimetallic Aerogels by Template-Free Self-Assembly of Au, Ag, Pt, and Pd Nanoparticles.</a> Chemistry of Materials. 26, 1074-1083 (2014).</li><li>Kornyshev, A., Irbakh, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Double-layer+capacitance+on+a+rough+metal+surface.">Double-layer capacitance on a rough metal surface.</a> Physical Review E. 53, 6192-6199 (1996).</li><li>Bisquert, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+the+boundaries+in+the+impedance+of+porous+film+electrodes.">Influence of the boundaries in the impedance of porous film electrodes.</a> Physical Chemistry Chemical Physics. 2, 4185-4192 (2000).</li><li>Bisquert, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Theory+of+the+Impedance+of+Electron+Diffusion+and+Recombination+in+a+Thin+Layer.">Theory of the Impedance of Electron Diffusion and Recombination in a Thin Layer.</a> Journal of Physical Chemistry B. 106, 325-333 (2002).</li><li>Lu, K., Yuan, L., Xin, X., Xu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hybridization+of+graphene+oxide+with+commercial+graphene+for+constructing+3D+metal-free+aerogel+with+enhanced+photocatalysis.">Hybridization of graphene oxide with commercial graphene for constructing 3D metal-free aerogel with enhanced photocatalysis.</a> Applied Catalysis B. 226, 16-22 (2018).</li><li>Nystron, G., Roder, L., Fernandez-Ronco, M., Mezzenga, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amyloid+Templated+Organic+Inorganic+Hybrid+Aerogels.">Amyloid Templated Organic Inorganic Hybrid Aerogels.</a> Advanced Functional Materials. , 1703609-1703620 (2017).</li></ol>

Yazarlar ifşa gerek yok.

Noble metal aerogel sentez yöntemi sonuçları daha yavaş sentez teknikleri için karşılaştırılabilir gözenekli, yüksek yüzey alanı yekpare hızlı oluşumunda burada sundu. İndirgeyici çözüm oranı 1:1 (v/v) metal iyon eriyik önerilen jel oluşumu modeli kolaylaştırmak önemlidir. Hızlı Hidrojen gaz evrim metal iyonları elektrokimyasal azalma bir yan ürün olarak ikincil bir indirgeyici hizmet vermektedir ve yoğunlaştırılması ve nano tanecikleri jel oluşumu sırasında büyüyen füzyon birli...

Enerji depolama ve dönüşüm, kataliz ve sensör uygulamaları geniş bir yarar--dan kimyasal reaktivite ve toplu taşıma özellikleri1,2üzerinde kontrol sağlayan üç boyutlu metalik nanoyapıların 3,4,5. Böyle daha fazla 3 boyutlu metalik nanoyapıların iletkenlik, süneklik, yumuşaklık ve gücü8,9geliştirmek. Entegrasyon cihazların içine malzeme müstakil veya destek malzemeleri ile birlikte olmasını gerektirir. Nanomalzemeler destek yapıları üzerine birleşme etkin malzeme en aza indirmek için bir yol sağlar, ancak zayıf adsorpsiyon ve aygıt işlemi10,11sırasında nihai Aglomerasyon muzdarip olabilir.
Bireysel nanopartikül boyutunu ve şeklini denetlemek için sentez yöntemleri çeşitli olmakla birlikte, birkaç yaklaşımlar bitişik 3 boyutlu Nanomalzemeler12,13,14üzerinde denetim sağlar. Noble metal 3 boyutlu nanoyapıların monodisperse nano tanecikleri, sol-jel oluşumu, nanopartikül birleştirme, kompozit malzemeler, nanosphere zincirler ve biotemplating15,16 dithiol bağlantı oluşturulmuştur , 17 , 18. çoğu bu yaklaşımlar, sentez kez gün ile istenen malzeme vermeye hafta sırasına gerektirir. Noble metal nanofoams habercisi tuz çözümleri doğrudan azalma sentezlenmiş mikrometre uzunluğunda yüzlerce kısa menzilli sırasını ve daha hızlı bir sentez zaman ölçeği ile hazırlanan, ancak aygıt tümleştirmesi için tuşuna basarak mekanik gerektirir 19 , 20.
İlk Kistler tarafından rapor, aerogels gözenekli yapıları ile büyüklük onların toplu malzeme karşıtları21,22,23 daha az yoğun olan yüksek belirli yüzey alanları elde etmek için bir sentez yol sağlamak . 3 boyutlu yapılara makroskopik uzunluk ölçek toplu malzemelerin uzanan nanopartikül toplamları veya destek malzemeleri veya mekanik işleme gerektiren nanofoams üzerinde bir avantaj sunuyor. Aerogels porozite ve parçacık özellik boyutu, ancak, kontrol etmek için bir sentez yol sentez zaman, sunarken ve bazı ajanlar veya bağlayıcı molekülleri, artar genel işlem adımları ve zaman sınırı kullanımını durumda.
Burada altın, paladyum, platin aerogels üzerinden bir hızlı, doğrudan çözüm tabanlı azaltma sentezlemek için bir yöntem24sunulmuştur. Azalan bakiyeli ajanlar bir 1:1 ile çeşitli öncü noble metal iyonları birleştirerek (v/v) oranı sonuçları saniye dakika içinde metal jelleri oluşumunda çok uzun sol-jel gibi diğer teknikleri sentezi süreleri karşılaştırıldığında. Microcentrifuge tüp veya küçük hacimli konik tüp kullanımı güçlü Hidrojen gaz evrim kolaylaştıran bir önerilen çekirdekleşme, büyüme, yoğunlaştırılması, Füzyon, jel oluşumu için denge modeli azaltma adım bir yan ürün olarak yararlanır. Aerogel nanostructure özelliği boyutlarda yakın bir ilişki elektron mikroskobu görüntü analizi, x-ışını diffractometry, azot gazı adsorpsiyon, elektrokimyasal empedans spektroskopisi ve çevrimsel voltammetry tarama ayarlarıyla belirlenir. Solvent erişilebilir belirli yüzey alanı elektrokimyasal empedans spektroskopisi ve çevrimsel voltammetry ile belirlenir. Bu sentez yöntemi noble metal aerogels için yüksek o belirli yüzey alanı yekpare bir hızlı ve doğrudan azaltma yaklaşımla elde gösterir.

<table border="0" cellpadding="0" cellspacing="0" width="691">
	<tbody>
		<tr height="25">
			<td height="25" style="height:25px;width:215px;">HAuCl4&#376;&#8226;3H2O&#160;</td>
			<td style="width:128px;">Sigma-Aldrich</td>
			<td style="width:119px;">16961-25-4</td>
			<td style="width:229px;"></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:215px;">Na2PdCl4</td>
			<td style="width:128px;">Sigma-Aldrich</td>
			<td style="width:119px;">13820-40-1</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:215px;">K2PtCl6</td>
			<td style="width:128px;">Sigma-Aldrich</td>
			<td style="width:119px;">16921-30-5</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">Pd(NH3)4Cl2</td>
			<td style="width:128px;">Sigma-Aldrich</td>
			<td style="width:119px;">13933-31-8</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">K2PtCl4</td>
			<td style="width:128px;">Sigma-Aldrich</td>
			<td style="width:119px;">10025-99-7</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">Pt(NH3)4Cl2&#376;&#8226;H2O</td>
			<td style="width:128px;">Sigma-Aldrich</td>
			<td style="width:119px;">13933-31-8</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">dimethylamine borane (DMAB)</td>
			<td style="width:128px;">Sigma-Aldrich</td>
			<td style="width:119px;">74-94-2</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:215px;">NaBH4</td>
			<td style="width:128px;">Sigma-Aldrich</td>
			<td style="width:119px;">16940-66-2</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:215px;">NaH2PO2&#376;&#8226;H2O</td>
			<td style="width:128px;">Sigma-Aldrich</td>
			<td style="width:119px;">10039-56-2</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Ethanol</td>
			<td style="width:128px;">Sigma-Aldrich</td>
			<td>792780</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Snap Cap Microcentrifuge Tubes, 2.0 mL</td>
			<td style="width:128px;">Cole Parmer</td>
			<td>UX-06333-70</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Snap Cap Microcentrifuge Tubes, 1.7 mL</td>
			<td style="width:128px;">Cole Parmer</td>
			<td>UX-06333-60</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Conical Centrifuge Tubes 15mL</td>
			<td style="width:128px;">Stellar Scientific</td>
			<td>T15-101&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Ag/AgCl Reference Electrode</td>
			<td style="width:128px;">BASi</td>
			<td style="width:119px;">MF-2052</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Pt wire electrode</td>
			<td style="width:128px;">BASi</td>
			<td style="width:119px;">MF-4130</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Miccrostop Lacquer</td>
			<td style="width:128px;">Tober Chemical Division</td>
			<td style="width:119px;">NA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Potentiostat</td>
			<td style="width:128px;">Biologic-USA</td>
			<td style="width:119px;">VMP-3</td>
			<td>Electrochemical analysis-EIS, CV</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Freeze Dryer</td>
			<td style="width:128px;">Labconco</td>
			<td style="width:119px;">Freezone 2.5 Liter</td>
			<td>Aerogel freeze drying</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">XRD</td>
			<td style="width:128px;">PanAlytical</td>
			<td style="width:119px;">Empyrean</td>
			<td>X-ray diffractometry</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Surface and Pore Analyzer</td>
			<td style="width:128px;">Quantachrome</td>
			<td style="width:119px;">NOVA 4000e</td>
			<td>Nitrogen gas adsorption</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">ImageJ, Image analysis software</td>
			<td style="width:128px;">National Institute of Health</td>
			<td style="width:119px;">NA</td>
			<td>SEM image analysis</td>
		</tr>
	</tbody>
</table>

a rapid synthesis method for au, pd, and pt aerogels via direct solution-based reduction

Burada, altın, paladyum, platin aerogels üzerinden bir hızlı, doğrudan çözüm tabanlı azaltma sentezlemek için bir yöntem sunulur. Çeşitli öncü noble metal iyonları saniye dakika içinde metal jelleri oluşumunda bir 1:1 (v/v) oranı sonuçlarında azalan bakiyeli ajanlar ile kombinasyonu çok uzun sol-jel gibi diğer teknikleri sentezi süreleri karşılaştırıldığında. Bir microcentrifuge azaltma adımda iletken tüp ya da küçük hacimli konik tüp kolaylaştırır bir önerilen çekirdekleşme, büyüme, yoğunlaştırılması, Füzyon, denge modeli ile son jel geometri ilk tepki ses daha küçük jel oluşumu için. Bu yöntem, güçlü Hidrojen gaz evrim azaltma adım ve reaktif konsantrasyonları bir sonucu olarak bir yan ürün olarak yararlanır. Solvent erişilebilir belirli yüzey alanı elektrokimyasal empedans spektroskopisi ve çevrimsel voltammetry ile belirlenir. Sonra durulama ve kurutma donma, elektron mikroskobu, x-ışını diffractometry ve azot gazı adsorpsiyon tarama ile elde edilen aerogel yapısı incelenir. Sentez yöntemi ve karakterizasyonu teknikleri aerogel bağ boyutları bir yakın yazışmalarda neden. Bu sentez yöntemi noble metal aerogels için yüksek o belirli yüzey alanı yekpare bir hızlı ve doğrudan azaltma yaklaşımla elde gösterir.

Metal iyon ve indirgeyici çözümleri birlikte sonuçları hemen dinç gaz evrim ile koyu siyah renk dönüm çözümlerinde eklenmesi. Şekil 1' de gösterilen önerilen jel oluşumu mekanizması gözlem reaksiyon ilerleme göstermektedir. Jel oluşumu 1) nanopartikül çekirdekleşme, 2) büyüme, 3) yoğunlaştırılması, 4) füzyon ve 5) denge beş adımları boyunca devam eder. İlk dört adımları ilk birkaç dakika boyunca 3-6 jel indirgeyici çöz?...

Watch this Scientific Journal Video about A Rapid Synthesis Method for Au, Pd, and Pt Aerogels Via Direct Solution-Based Reduction at JoVE.com

A Rapid Synthesis Method for Au, Pd, and Pt Aerogels Via Direct Solution-Based Reduction

Otomatik Güncelleştirmeler, Pd ve Pt Aerogels üzerinden doğrudan çözüm tabanlı azaltma için hızlı sentez yöntemi

Otomatik Güncelleştirmeler, Pd ve Pt aerogels elde etmek için hızlı, doğrudan çözüm tabanlı azaltma sentez yöntemi gösterilir.

Here, a method to synthesize gold, palladium, and platinum aerogels via a rapid, direct solution-based reduction is presented. The combination of various ...

a-rapid-synthesis-method-for-au-pd-pt-aerogels-via-direct-solution

Universidad San Sebastian

Research

JoVE Journal

Chemistry

8.6K Görüntüleme.  United States Military Academy, West Point. Otomatik Güncelleştirmeler, Pd ve Pt aerogels elde etmek için hızlı, doğrudan çözüm tabanlı azaltma sentez yöntemi gösterilir.

Video: A Rapid Synthesis Method for Au, Pd, and Pt Aerogels Via Direct Solution-Based Reduction

Preparing Silica Aerogel Monoliths via a Rapid Supercritical Extraction Method

A procedure for the fabrication of monolithic silica aerogels in eight hours or less via a rapid supercritical extraction process is described. The procedure requires 15-20 min of preparation time, during which a liquid precursor mixture is prepared and poured into wells of a metal mold that is placed between the platens of a hydraulic hot press, followed by several hours of processing within the hot press. The precursor solution consists of a 1.0:12.0:3.6:3.5 x 10-3 molar ratio of tetramethylorthosilicate (TMOS):methanol:water:ammonia. In each well of the mold, a porous silica sol-gel matrix forms. As the temperature of the mold and its contents is increased, the pressure within the mold rises. After the temperature/pressure conditions surpass the supercritical point for the solvent within the pores of the matrix (in this case, a methanol/water mixture), the supercritical fluid is released, and monolithic aerogel remains within the wells of the mold. With the mold used in this procedure, cylindrical monoliths of 2.2 cm diameter and 1.9 cm height are produced. Aerogels formed by this rapid method have comparable properties (low bulk and skeletal density, high surface area, mesoporous morphology) to those prepared by other methods that involve either additional reaction steps or solvent extractions (lengthier processes that generate more chemical waste).The rapid supercritical extraction method can also be applied to the fabrication of aerogels based on other precursor recipes.

This article describes a rapid supercritical extraction method for fabricating silica aerogels. By utilizing a confined mold and hydraulic hot press, monolithic aerogels can be made in eight hours or less.

Bir Rapid Süperkritik Ekstraksiyon Yöntemi ile Silika AEROJEL Monoliths hazırlanıyor

A procedure for the fabrication of monolithic silica aerogels in eight hours or less via a rapid supercritical extraction process is described. The ...

Kimya

Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large extinction coefficients which can be tuned across the visible spectrum. Research into the plasmonic enhancement of optical transitions has become popular, due to the possibility of altering and in some cases improving photo-absorption or emission properties of nearby chromophores such as molecular dyes or quantum dots. The electric field of the plasmon can couple with the excitation dipole of a chromophore, perturbing the electronic states involved in the transition and leading to increased absorption and emission rates. These enhancements can also be negated at close distances by energy transfer mechanism, making the spatial arrangement of the two species critical. Ultimately, enhancement of light harvesting efficiency in plasmonic solar cells could lead to thinner and, therefore, lower cost devices. The development of hybrid core/shell particles could offer a solution to this issue. The addition of a dielectric spacer between a gold nanoparticles and a chromophore is the proposed method to control the exciton plasmon coupling strength and thereby balance losses with the plasmonic gains. A detailed procedure for the coating of gold nanoparticles with CdS and ZnS semiconductor shells is presented. The nanoparticles show high uniformity with size control in both the core gold particles and shell species allowing for a more accurate investigation into the plasmonic enhancement of external chromophores.

The synthesis of uniform gold nanoparticles coated with semiconductor shells of CdS or ZnS is performed. The semiconductor coating is conducted by first depositing a silver sulfide shell and exchanging the silver cations for zinc or cadmium cations.

Sentezi, Karakterizasyonu ve Hibrid Au / CdS ve Au / ZnS Çekirdek / Shell Nanopartiküller işlevselleştirilmesi

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large ...

A Method to Manipulate Surface Tension of a Liquid Metal via Surface Oxidation and Reduction

Controlling interfacial tension is an effective method for manipulating the shape, position, and flow of fluids at sub-millimeter length scales, where interfacial tension is a dominant force. A variety of methods exist for controlling the interfacial tension of aqueous and organic liquids on this scale; however, these techniques have limited utility for liquid metals due to their large interfacial tension.
Liquid metals can form soft, stretchable, and shape-reconfigurable components in electronic and electromagnetic devices. Although it is possible to manipulate these fluids via mechanical methods (e.g., pumping), electrical methods are easier to miniaturize, control, and implement. However, most electrical techniques have their own constraints: electrowetting-on-dielectric requires large (kV) potentials for modest actuation, electrocapillarity can affect relatively small changes in the interfacial tension, and continuous electrowetting is limited to plugs of the liquid metal in capillaries.
Here, we present a method for actuating gallium and gallium-based liquid metal alloys via an electrochemical surface reaction. Controlling the electrochemical potential on the surface of the liquid metal in electrolyte rapidly and reversibly changes the interfacial tension by over two orders of magnitude ( &#820;500 mN/m to near zero). Furthermore, this method requires only a very modest potential (&#60; 1 V) applied relative to a counter electrode. The resulting change in tension is due primarily to the electrochemical deposition of a surface oxide layer, which acts as a surfactant; removal of the oxide increases the interfacial tension, and vice versa. This technique can be applied in a wide variety of electrolytes and is independent of the substrate on which it rests.

We present a method to control the interfacial energy of a liquid metal in an electrolyte via electrochemical deposition (or removal) of a surface oxide layer. This simple method can control the capillary behavior of gallium-based liquid metals by tuning the interfacial energy rapidly, significantly, and reversibly using modest voltages.

Bir Yöntem Yüzey Oksidasyon ve İndirgeme yoluyla Sıvı Metal Yüzey Gerilim işleyin

Controlling interfacial tension is an effective method for manipulating the shape, position, and flow of fluids at sub-millimeter length scales, where ...

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the development of antibody drug conjugates (ADCs) and nanomedicine, fluorescent microscopy and systems chemistry. For many of these applications, specificity of the bioconjugation method used is of prime concern. The Michael addition of maleimides with cysteine(s) on the target proteins is highly selective and proceeds rapidly under mild conditions, making it one of the most popular methods for protein bioconjugation.
We demonstrate here the modification of the only surface-accessible cysteine residue on yeast cytochrome c with a ruthenium(II) bisterpyridine maleimide. The protein bioconjugation is verified by gel electrophoresis and purified by aqueous-based fast protein liquid chromatography in 27% yield of isolated protein material. Structural characterization with MALDI-TOF MS and UV-Vis is then used to verify that the bioconjugation is successful. The protocol shown here is easily applicable to other cysteine - maleimide coupling of proteins to other proteins, dyes, drugs or polymers.

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

This protocol details the important steps required for the bioconjugation of a cysteine containing protein to a maleimide, including reagent purification, reaction conditions, bioconjugate purification and bioconjugate characterization.

Protein Bioconjugatlar sentezi<em&gt; yoluyla</em&gt; Sistein-maleimid Kimya

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the ...

Combining Solid-state and Solution-based Techniques: Synthesis and Reactivity of Chalcogenidoplumbates(II or IV)

The phases of &#34;PbCh2&#34; (Ch = Se, Te) are obtained from solid-state syntheses (i.e., by the fusion of the elements under inert conditions in silica glass ampules). Reduction of such phases by elemental alkaline metals in amines affords crystalline chalcogenidoplumbate(II) salts comprised of [PbTe3]2- or [Pb2Ch3]2- anions, depending upon which sequestering agent for the cations is present: crown ethers, like 18-crown-6, or cryptands, like [2.2.2]crypt. Reactions of solutions of such anions with transition-metal compounds yield (poly-)chalcogenide anions or transition-metal chalcogenide clusters, including one with a &#181;-PbSe ligand (i.e., the heaviest-known CO homolog).
In contrast, the solid-state synthesis of a phase of the nominal composition &#34;K2PbSe2&#34; by successive reactions of the elements and by the subsequent solvothermal treatment in amines yields the first non-oxide/halide inorganic lead(IV) compound: a salt of the ortho-selenidoplumbate(IV) anion [PbSe4]4-. This was unexpected due to the redox potentials of Pb(IV) and Se(-II). Such methods can further be applied to other elemental combinations, leading to the formation of solutions with binary [HgTe2]2- or [BiSe3]3- anions, or to large-scale syntheses of K2Hg2Se3 or K3BiSe3 via the solid-state route.
All compounds are characterized by single-crystal X-ray diffraction and elemental analysis; solutions of plumbate salts can be investigated by 205Pb and 77Se or 127Te NMR techniques. Quantum chemical calculations using density functional theory methods enable energy comparisons. They further allow for insights into the electronic configuration and thus, the bonding situation. Molecular Rh-containing Chevrel-type compounds were found to exhibit delocalized mixed valence, whereas similar telluridopalladate anions are electron-precise; the cluster with the &#181;-PbSe ligand is energetically favored over a hypothetical CO analog, in line with the unsuccessful attempt at its synthesis. The stability of formal Pb(IV) within the [PbSe4]4- anion is mainly due to a suitable stabilization within the crystal lattice.

Combining Solid-state and Solution-based Techniques: Synthesis and Reactivity of ChalcogenidoplumbatesII or IV

The synthesis of chalcogenidoplumbates(II,IV) via the in situ reduction of nominal "PbCh2" (Ch = Chalcogen) and via a solid-state reaction and subsequent solvothermal reactions is presented. Additionally, reactivities of plumbate(II) solutions are portrayed, which yield the heaviest-known CO homolog known to date: the &#181;-PbSe ligand.

Katı-devlet ve Çözüm tabanlı Teknikleri birleştiren: Sentez ve Chalcogenidoplumbates ve Reaktifite (II veya IV)

The phases of &#34;PbCh2&#34; (Ch = Se, Te) are obtained from solid-state syntheses (i.e., by the fusion of the elements under inert conditions in silica ...

Synthesis and Testing of Supported Pt-Cu Solid Solution Nanoparticle Catalysts for Propane Dehydrogenation

A convenient method for the synthesis of bimetallic Pt-Cu catalysts and performance tests for propane dehydrogenation and characterization are demonstrated here. The catalyst forms a substitutional solid solution structure, with a small and uniform particle size around 2 nm. This is realized by careful control over the impregnation, calcination, and reduction steps during catalyst preparation and is identified by advanced in situ synchrotron techniques. The catalyst propane dehydrogenation performance continuously improves with increasing Cu:Pt atomic ratio.

A convenient method for the synthesis of 2 nm supported bimetallic nanoparticle Pt-Cu catalysts for propane dehydrogenation is reported here. In situ synchrotron X-ray techniques allow for the determination of the catalyst structure, which is typically unobtainable using laboratory instruments.

Propan Dehidrojenasyon için Desteklenen Pt-Cu Katı Solüsyon Nanopartikül Katalizörlerinin Sentezi ve Testi

A convenient method for the synthesis of bimetallic Pt-Cu catalysts and performance tests for propane dehydrogenation and characterization are ...

Synthesis of Platinum-nickel Nanowires and Optimization for Oxygen Reduction Performance

Platinum-nickel (Pt-Ni) nanowires were developed as fuel cell electrocatalysts, and were optimized for the performance and durability in the oxygen reduction reaction. Spontaneous galvanic displacement was used to deposit Pt layers onto Ni nanowire substrates. The synthesis approach produced catalysts with high specific activities and high Pt surface areas. Hydrogen annealing improved Pt and Ni mixing and specific activity. Acid leaching was used to preferentially remove Ni near the nanowire surface, and oxygen annealing was used to stabilize near-surface Ni, improving durability and minimizing Ni dissolution. These protocols detail the optimization of each post-synthesis processing step, including hydrogen annealing to 250 &#176;C, exposure to 0.1 M nitric acid, and oxygen annealing to 175 &#176;C. Through these steps, Pt-Ni nanowires produced increased activities more than an order of magnitude than Pt nanoparticles, while offering significant durability improvements. The presented protocols are based on Pt-Ni systems in the development of fuel cell catalysts. These techniques have also been used for a variety of metal combinations, and can be applied to develop catalysts for a number of electrochemical processes.

&#160; The protocol describes the synthesis and electrochemical testing of platinum-nickel nanowires. Nanowires were synthesized by the galvanic displacement of a nickel nanowire template. Post-synthesis processing, including hydrogen annealing, acid leaching, and oxygen annealing were used to optimize nanowire performance and durability in the oxygen reduction reaction.

Platin-nikel Nanowires ve oksijen azaltma performansı için en iyi duruma getirme sentezi

Platinum-nickel (Pt-Ni) nanowires were developed as fuel cell electrocatalysts, and were optimized for the performance and durability in the oxygen ...

Fabrication and Testing of Catalytic Aerogels Prepared Via Rapid Supercritical Extraction

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three preparation methods are described: (a) the incorporation of metal salts into silica or alumina wet gels using an impregnation method; (b) the incorporation of metal salts into alumina wet gels using a co-precursor method; and (c) the addition of metal nanoparticles directly into a silica aerogel precursor mixture. The methods utilize a hydraulic hot press, which allows for rapid (&#60;6 h) supercritical extraction and results in aerogels of low density (0.10 g/mL) and high surface area (200-800 m2/g). While the work presented here focuses on the use of copper salts and copper nanoparticles, the approach can be implemented using other metal salts and nanoparticles. A protocol for testing the three-way catalytic ability of these aerogels for automotive pollution mitigation is also presented. This technique uses custom-built equipment, the Union Catalytic Testbed (UCAT), in which a simulated exhaust mixture is passed over an aerogel sample at a controlled temperature and flow rate. The system is capable of measuring the ability of the catalytic aerogels, under both oxidizing and reducing conditions, to convert CO, NO and unburned hydrocarbons (HCs) to less harmful species (CO2, H2O and N2). Example catalytic results are presented for the aerogels described.

Here we present protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms. Methods for preparing materials using copper salts and copper-containing nanoparticles are featured. Catalytic testing protocols demonstrate the effectiveness of these aerogels for three-way catalysis applications.

İmalat ve katalitik Aerogels hızlı süperkritik ayıklama hazırlanan test

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three ...

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction

This protocol presents both the synthesis method of the Ni single atom catalyst, and the electrochemical testing of its catalytic activity and selectivity in aqueous CO2 reduction. Different from traditional metal nanocrystals, the synthesis of metal single atoms involves a matrix material that can confine those single atoms and prevent them from aggregation. We report an electrospinning and thermal annealing method to prepare Ni single atoms dispersed and coordinated in a graphene shell, as active centers for CO2 reduction to CO. During the synthesis, N dopants play a critical role in generating graphene vacancies to trap Ni atoms. Aberration-corrected scanning transmission electron microscopy and three-dimensional atom probe tomography were employed to identify the single Ni atomic sites in graphene vacancies. Detailed setup of electrochemical CO2 reduction apparatus coupled with an on-line gas chromatography is also demonstrated. Compared to metallic Ni, Ni single atom catalyst exhibit dramatically improved CO2 reduction and suppressed H2 evolution side reaction.

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction

Here, we present a protocol for the synthesis and electrochemical testing of transition metal single atoms coordinated in graphene vacancies as active centers for selective carbon dioxide reduction to carbon monoxide in aqueous solutions.

Sentez ve elektrokimyasal CO2 azaltılması için geçiş metalleri tek Atom katalizör performans karakterizasyonu

This protocol presents both the synthesis method of the Ni single atom catalyst, and the electrochemical testing of its catalytic activity and selectivity ...

Synthesis of Substrate-Bound Au Nanowires Via an Active Surface Growth Mechanism

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a challenge, as it requires asymmetric growth of symmetric crystals. Here, we report a distinctive synthesis of substrate-bound Au nanowires. This template-free synthesis employs thiolated ligands and substrate adsorption to achieve the continuous asymmetric deposition of Au in solution at ambient conditions. The thiolated ligand prevented the Au deposition on the exposed surface of the seeds, so the Au deposition only occurs at the interface between the Au seeds and the substrate. The side of the newly deposited Au nanowires is immediately covered with the thiolated ligand, while the bottom facing the substrate remains ligand-free and active for the next round of Au deposition. We further demonstrate that this Au nanowire growth can be induced on various substrates, and different thiolated ligands can be used to regulate the surface chemistry of the nanowires. The diameter of the nanowires can also be controlled with mixed ligands, in which another &#34;bad&#34; ligand could turn on the lateral growth. With the understanding of the mechanism, Au nanowire-based nanostructures can be designed and synthesized.

We report a solution-based method to synthesize substrate-bound Au nanowires. By tuning the molecular ligands used during the synthesis, the Au nanowires can be grown from various substrates with different surface properties. Au nanowire-based nanostructures can also be synthesized by adjusting the reaction parameters.