作者衷心感谢英国工程与物理科学研究理事会（资助参考号:EP / M003299 / 1）和中国自然科学基金（51461135005）国际联合研究项目（EPSRC-NSFC）的资助。

1.合成TiO 2 -SiO 2复合材料<ol><li> 基于商业石英的样品 注意:粒度在20-100μm范围内的石英通过球磨商业石英15分钟和筛分获得。然后通过两种不同的方法用TiO 2改性粉末。 <ol><li> QT1 <ol><li>通过将TBOT（2.6mL）溶解在乙醇（29.6mL）中，制备作为TiO 2前体9的10％的钛（IV）丁醇溶液（TBOT; 97％）的乙醇溶液。 </li><li>通过连续搅拌将3g石英粉末悬浮在30g新制备的钛前体溶液中。 </li><li>加入0.3mL盐酸（32％）。搅拌所得悬浮液5分钟。 </li><li>加入30毫升去离子水，并连续搅拌混合物过夜。 </li><li>将所有粘稠悬浮液转移到培养皿中，并在环境条件下储存溶剂已完全蒸发。 </li><li>用去离子水洗涤经处理的石英数次，然后在90℃下干燥过夜。 </li><li>在400℃下热处理20小时。 </li><li>将粉末在空气中冷却并再次筛分以收集大于20μm的颗粒。将改性石英与松散或不连接的TiO 2分离 。 </li></ol></li><li> QT2 注意: 通过如下来自原硅酸四乙酯（TEOS）的硅胶粘合剂在石英上支撑商业光催化剂（PC105）。 <ol><li>通过将TEOS（23.2mL）溶解在乙醇（29.2mL）中来制备TEOS母溶液。然后加入去离子水（7.2mL）和HCl（0.4mL; 3.6wt。％），得到最终的乙醇:水:HCl混合物（1:0.884:0.78×10 -3摩尔比）。将混合物在室温下搅拌10天。 </li><li>将精确体积的所得溶液加入到100mL乙醇中，其中悬浮0.2g TiO 2 ，得到TiO 2 :TEOS为1:1。 </li><li>在室温下轻轻搅拌过夜，然后在80℃，减压下连续搅拌下将悬浮液滴加到2g石英中。 </li><li>将所得粉末在90℃下干燥过夜，然后在200℃下热处理4小时。 </li></ol></li></ol></li><li> 基于合成二氧化硅的样品 <ol><li> ST1 注意:通过水解控制的溶胶 - 凝胶技术在沉淀的SiO 2表面上沉积TiO 2纳米颗粒。 <ol><li> 通过 Stoeber-Bohn-Fink方法合成单分散二氧化硅微球14 。 </li><li>溶解于乙醇（40mL）中的TEOS（5mL）并搅拌30分钟（溶液A）。 </li><li>通过在连续搅拌下将氨溶液（8mL; 25wt。％）与去离子水（30mL）和乙醇（18mL）混合30分钟来制备溶液B. </li><li>快速添加l的溶液A溶于溶液B，并在室温下搅拌3小时。 </li><li>通过离心收集所得的SiO 2 （1,252×g）。用无水乙醇洗涤3次，在105℃下干燥48小时。 </li><li>通过在超声波浴中将1g悬浮在30mL乙醇中10分钟来制备所生产的SiO 2的悬浮液。将悬浮液再搅拌30分钟。 </li><li>小心地加入1mL TBOT（97％）到乙醇的SiO 2悬浮液中。 </li><li>将混合物在室温下搅拌24小时。 </li><li>加入去离子水（2mL）和乙醇（8mL），然后将混合物进一步搅拌2小时。 </li><li>通过离心收集改性粉末，用乙醇洗涤3次。在105℃下干燥48小时，然后在500℃下热处理3小时。 注意:T1:为了比较，TiO 2通过相同的方法制备，但是在不存在二氧化硅的情况下。 </li></ol></li><li> ST2 </st荣&gt; 注意:在这些样品中，如下分别合成SiO 4 / TiO 2摩尔比为0.25的原始硅酸四乙酯（TEOS）和四异丙醇钛（TTIP）的前体Si / Ti的均匀凝胶。 <ol><li>将所需量的TEOS（0.89mL）滴加到乙醇:水:HCl混合物（73.6mL; 1:0.84:0.78×10 -3摩尔比）中。 </li><li>在室温下搅拌1小时。 </li><li>加入所需量的TTIP（4.74mL），并将混合物在室温下进一步搅拌过夜。 </li><li>通过在80℃下搅拌1小时来实现溶胶 - 凝胶转化。 </li><li>热处理所得凝胶如下:在90℃，450℃，5小时，500℃下干燥5小时。 注意:T2 :纯TiO 2也通过相同的溶胶 - 凝胶法制备，但在不存在TEOS的情况下。 </li></ol></li></ol></li></ol>特征ñ <ol><li>使用配有UATR（单反射钻石） 15的分光光度计记录IR光谱。 </li><li>使用配备有CuKa1 1.54A X射线源16的PAN分析衍射仪获得X射线衍射（XRD）图案。 </li><li>通过扫描电子显微镜（SEM）分析样品的形态，配备ED X射线分析仪和BSE检测器，工作电压在10 - 20 kV之间。使用数字图像采集系统进行能量色散X射线分析和捕获图像。 </li><li>在加速电压为200 kV的显微镜下进行透射电子显微镜（TEM）。用相机拍摄图像。 </li><li>使用配有光纤耦合器的UV-Vis分光光度计记录样品的UV-Vis漫反射光谱。 使用硫酸钡作为参考，范围为250至600 nm。将所得到的反射光谱转化为明显的吸收通过使用Kubelka-Munk函数F（R∞）=（1-R∞） 2 /2R∞17的光谱 。 </li></ol>光催化性能测试<ol><li>使用从污染空气中除去NOx来测试制备的材料的光催化活性。 <ol><li>为此，建立由气体供应，加湿器（2），气体流量控制器（1），光催化反应器（3），UV（A）光源（4）组成的空气净化测试装置（ 见图1 ）和NOx分析器（5）。气体供应在N 2中为NO（100ppm），合成空气（BOC）为空气。 </li><li>使用质量流量控制器（1）为1 ppmv（0.5 ppmv，对于ST1和T1样品）提供NO，相对湿度为约40％，由Rotronic hygropalm确认，以5×10 -5 m 3 * s -1 （1.675×10 -5 m）的体积流量向层流反应器（3） <su在ST1和T1样本的情况下，p&gt; 3 * s -1 ）。 </li><li>从PMMA（聚（甲基丙烯酸甲酯））构建光反应器并用硼硅酸盐玻璃覆盖。将其设置在配备1.5 AM滤波器的SS0.5 kW，500 W全反射太阳能模拟器的输出下方，以确保测试样品（6）在λ&lt;420 nm处接收到10 Wm -2的光强度，如测量通过宽带热电堆检测器。 </li><li>使用NO-NO 2 -NOx分析仪监测出口气体流中NO，NO 2和总NOx的浓度。 </li></ol></li></ol><img alt="图1" class="xfigimg" src="/files/ftp_upload/56070/56070fig1.jpg" /> 图1: 用于光催化测试的实验装置:（1）质量流量控制器（2）加湿器（3）光催化反应器（4） UV（A）光源<stron（5）NOx分析仪（6）试样（7）和（8）阀， （9）气流出口。 <a href="http://ecsource.jove.com/files/ftp_upload/56070/56070fig1large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> <ol start="2"><li>通过将材料的0.8g（0.3g，ST1和T1样品的情况）压入矩形PMMA夹具（高度为0.2cm，宽3cm，长8cm）中来制备测试样品。 <ol><li>用UV（320nm）将几何表面积为2.4×10 -3 m 2的所得团块辐射过夜，以除去其表面上吸附的任何有机污染物。 </li></ol></li></ol>

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作者没有什么可以披露的。

图8显示了每种光催化材料的NO光子效率之间的显着差异。支持光催化剂增加反应性表面的可及性的优点现在已经很好地建立，值得注意的是PC105和支持的处理石英（QT2）上的PC105的NO氧化的光子效率之间的区别。 ζNO（QT2）测量值为PC105的73％，但QT2仅占TiO 2负载量的6.5％。显然，活动改进在支持的系统上是重要的，但是当解释具有显着形态学差异的测量值时应该谨慎。 可以预期影响测量的光催化测试系统的关键特征是支撑在光催化反应器中的样品的表面纹理。这会影响有效的表面积。计算ξ包括区域项，但这是由反应堆样品架定义的照明的二维区域。 TiO 2粉末，即PC105，T1和T2的粒度分布与复合材料完全不同，其中TiO 2 &#39;粉末负载在直径在0.4-50μm的SiO 2上。这意味着光催化剂表面纹理是非常可变的，并且预期会影响所报道的光子效率。它还影响反应器流动特性。由于包装特性，质地越粗糙，所需层流状态越可能被破坏。这预计会影响气体分子扩散到表面的速率，从而影响光子效率测量。 作为这些效应的结果，光催化剂类型的最有用的比较必须基于从单个催化剂上测量得到的性质。在这个研究中，硝酸盐选择性，其基于ξNO和ξNO 2 （等式10），在同一样品上测量的都用于随后的讨论。 <img alt="公式3" src="/files/ftp_upload/56070/56070eq3.jpg" /> （10） <img alt="图9" class="xfigimg" src="/files/ftp_upload/56070/56070fig9.jpg" /> 图9:对于不同TiO 2和TiO 2 -SiO 2复合粉末记录的NO x的总去除的选择性， 即硝酸盐选择性。直接比较的系统用相同的符号标识，支持的和不支持的对。 <a href="http://ecsource.jove.com/files/ftp_upload/56070/56070fig9large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> 控制硝酸盐选择性的因素似乎是复杂的，相关的变量包括de TiO 2多态性，缺陷状态，水的可利用性等 7 ，但是现在也可以考虑通常被认为对光催化性能有利的底物结合的作用。因此，讨论非键合和键合体系之间的硝酸盐选择性差异是有益的，即独立光催化剂与光催化剂载体复合材料， 如 PC105 与 QT2;其中QT2表示支持在石英上的硅酸盐涂层中的PC105。这些硝酸盐选择性差异总结在表1中 。 <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td> 光触媒 </td><td> 光触媒支持 </td><td> DSelectivity（％）; （相对选择性降低（％）） </td><td> FTIR峰面积比; （Ti-O-Si）/ SiO 2 </td><td> Ti-O-Si peak中心（cm -1 ） </td></tr><tr><td> PC105 </td><td> QT2 </td><td> （38.8-28.3）= 10.5; （-27） </td><td> 0.0088 </td><td> 960 </td></tr><tr><td> T1 </td><td> ST1 </td><td> （16.0-10.6）= 5.4; （1-34） </td><td> 0.0184 </td><td> 960 </td></tr><tr><td> T2 </td><td> ST2 </td><td> （33.4-0）= 33.4; （-100） </td><td> 0.6566 </td><td> 920 </td></tr><tr><td> T1 </td><td> QT1 </td><td> （16.0-15.6）= 0.4; （-3） </td><td> 0.0014 </td><td> 930 </td></tr></tbody></table> 表1:复合形成和Ti-O-Si键合对光催化剂性能的影响。使用Origin Peak Analyzes软件从图5中获得了分配给Ti-O-Si（920-990cm -1 ）和SiO 2 （990-1230cm -1 ）的峰的背景校正FTIR峰面积。无量纲区域r将表1中所示的atio作为复合体系中Ti-O-Si键合程度的量度。还示出了与Ti-O-Si键相关联的峰中心位置。这些数据总结在图10中 。 <img alt="图10" class="xfigimg" src="/files/ftp_upload/56070/56070fig10.jpg" /> 图10: 不同TiO 2材料的硝酸盐选择性的相对降低与SiO 2作为光催化剂载体复合材料中Ti-O-Si键合的功能相结合。 <a href="http://ecsource.jove.com/files/ftp_upload/56070/56070fig10large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> 对于光催化剂T2组合时，复合材料形成的最大选择性降低， 即对环境空气质量产生最大负面影响的选择性降低与硅酸盐前体。产生高度分散的凝胶，其中Ti-O-Si键最大化。峰面积分析表明，大约65摩尔％的TiO 2与SiO 2通过Ti-O-Si连接相关，其接近准备物的化学计量TiO 2 :SiO 2比（80％），并提供了对峰面积比分析。还值得注意的是，Ti-O-Si峰中心位于复合材料观察到的最低波数处，并表明组成信息可能嵌入到Ti-O-Si峰特征中。所有其他复合材料显示出相当低的（Ti-O-Si）/ SiO 2峰面积比，表明较低的Ti-O-Si键合水平。图10显示，这种结合水平与选择性相关，表示为自由式催化剂选择性的百分比降低，表明Ti-O-Si结合对光催化NOx减少具有负面影响。 这些发现的结果是必须达成妥协，以确保粘合体系的物理耐久性，而不会明显地损失光催化性能。可能的方法可以包括:（i）增加支持的TiO 2粒度，使得限定"独立"光催化剂的固有光催化性能的有益Ti-O-Ti键不被Ti-O-Si连接，和/或（ii）为基材制造薄的，多孔的和耐久的表面涂层，使得光催化剂被捕获在反应物气体分子和照明可接近的孔中。 石英砂或反应性二氧化硅球形式的二氧化硅已经用TiO 2通过结合商业TiO 2光催化剂（PC105），利用硅酸盐基粘合剂或通过不同Ti前体的水解缩合反应成功地改性。光催化将所得复合材料的性能与促进高水平Ti-O-Si结合键的溶胶 - 凝胶衍生的混合氧化物体系的性能进行了比较。主要研究结果表明:（i）混合氧化物制备中TiO 2 -SiO 2的结合程度如预期的高（65％），并且在制备中接近化学计量的TiO 2 :SiO 2比例。该复合凝胶体系与可比溶胶 - 凝胶衍生的TiO 2 （T2）相比，显示出不含硝酸盐的选择性，其显示出33％的选择性，（ii）随着硅酸盐表面的反应性降低，Ti-O-Si结合度降低;顺序为石英（QT2）&gt;石英石英反应性二氧化硅球（ST1）&gt;硅酸盐凝胶层，（iii）TiO 2的硝酸盐选择性受到Ti-O-Si键合水平的不利影响。

混凝土结构在我们的社会中普遍存在。通常与我们的城市中心相关联，其显着的表面积是城市大气的重要界面1,2 。随着对城市空气质量恶化的经济和健康影响的关注越来越多，这一接口为大气补救提供了重要的机会。 TiO 2基光催化剂已经被用于NOx污染空气的修复中一段时间​​，并且它们在这些高表面积混凝土结构上的支撑提供了先前与光催化材料相关的附加功能:（i）易于清洁，其中材料将污垢结合到表面的光催化降解，使污垢容易用雨水洗掉3 ; （ii）光诱导的亲水性，这也增强了自清洁效果3;和（iii）净化今天的城市大气，通常被车辆排放污染，水平显着超过最大允许水平，特别是对于NOx 4 。 TiO 2是环境应用中最常用的光催化剂，由于其化学稳定性，价格相对较低，光催化活性高，更重要的是其目前可用的二氧化钛毒理学数据所表明的生态安全性。 光催化混凝土已经在欧洲和其他地方的试验地点展示了其对大气修复的潜力。过去二十年来，许多关于光催化水泥材料的研究主要涉及催化剂活性，通常以NOx浓度降低1,6,7 <sup&gt;， 8，9 。然而，单独的活动是光催化效力的指标不足。定义为大气氮氧化物浓度的总和的NOx浓度的降低本身不代表对空气质量的有用影响，因为构成气体的相对毒性不等同于10 。 NOx气体的光催化氧化遵循顺序 NO→HONO→NO 2 →HONO 2 （NO 3 - ） NO 2相对于NO的毒性越高（保守地为3× 10 ），意味着NO的氧化转化为硝酸盐（ 即 硝酸盐选择性 ）必须最大化。因此，提供高活动和高硝酸盐的手段<html>选择性必须是针对性的。 至于一般的催化剂，需要高表面积来吸附反应分子。纳米颗粒TiO 2确保高光催化活性所需的高比表面积，提供颗粒充分分散9 。然而，当通过混合到水泥粘合剂中时，可能发生凝聚，降低有效表面积，并且水泥水合反应可导致光催化剂闭塞，进一步减少可接近的表面积并阻止催化剂活化阳光1,11 。 因此，在更有效的光催化结构中更好地保​​存可接触的催化剂表面积时，可以预期显着改善的性能。它们包括负载在混凝土表面暴露的骨料和沸石结构中的催化剂ass ="xref"&gt; 2，12 。这些结构的耐久性在很大程度上取决于催化剂对各种载体的结合程度。在文献8,13中经常提到将TiO 2化学键合到底物的优点，但是表征结合程度的手段是不明确的。然而，相对于物理吸引力的化学键的完整性提供了在混凝土表面上形成坚固结构的机会。然而，TiO 2与底物（ 例如石英）之间的化学键对载体TiO 2的光学和光催化性能的影响，提供了Ti-O-Si键，这一点以前没有进行过研究。因此，本工作的重点是建立生成和量化Ti-O-Si键的水平的手段，并将其与光催化相关联负载TiO 2的性质。为此，通过不同的方法将商业和合成的TiO 2结合到石英SiO 2砂（作为聚集体的简单实例）上。

<table border="0" cellpadding="0" cellspacing="0" width="888">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:227px;">quartz</td>
			<td style="width:163px;">Aldrich</td>
			<td align="right" style="width:211px;">31623</td>
			<td style="width:289px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">tetrabutylorthotitania (TBOT)</td>
			<td>Aldrich</td>
			<td align="right">244112</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">ethanol</td>
			<td>Aldrich</td>
			<td></td>
			<td>absolute alcohol</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">hydrochloric acid</td>
			<td>Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">deionised water</td>
			<td></td>
			<td></td>
			<td>18.2 MW&#937;.cm</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">seives</td>
			<td>Endecott</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">tetraethylorthosilicate (TEOS)</td>
			<td>Aldrich</td>
			<td align="right">86578</td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;">PC105 (TiO2)</td>
			<td>Cristal Global</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">ammonia solution</td>
			<td>Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">titanium tetraisopropoxide (TTIP)</td>
			<td>Aldrich</td>
			<td align="right">87560</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">barium sulphate</td>
			<td>Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;">NO in N2&#160;</td>
			<td>BOC</td>
			<td></td>
			<td>100 ppm</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:227px;">FTIR spectrophotometer</td>
			<td>Perkin Elmer</td>
			<td>Spectrum Two&#160;</td>
			<td>equipped with UATR</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">X-ray diffractometer</td>
			<td>PAN analytical&#160;</td>
			<td>X&#39;Pert3 Powder</td>
			<td>equipped with a CuKa1 1.54 &#197; X-ray source</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Scanning electron microscope</td>
			<td>ISI</td>
			<td>ABT55</td>
			<td>ED X-ray analyser and Link Analytical BSE detector&#160;</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Transmission electron microscope</td>
			<td>Jeol</td>
			<td>JEM-2000EX&#160;</td>
			<td>utilising a Gatan Erlangshen ES500W camera</td>
		</tr>
		<tr height="39">
			<td height="39" style="height:39px;width:227px;">UV-vis diffuse reflectance spectrophotometer</td>
			<td>Agilent Technology</td>
			<td>Cary 60&#160;</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Mass flow controllers</td>
			<td>Bronkhorst</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Humidity monitor</td>
			<td>Rotronic</td>
			<td>Hygropalm</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Solar simulator</td>
			<td>Sciencetech</td>
			<td>SS0.5kW</td>
			<td>1.5 AM filter used</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Broadband thermopile detector</td>
			<td>Gentec EO</td>
			<td>XLP12-3S-H2-D0</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">NOx analyser</td>
			<td>Air Monitors Ltd</td>
			<td>Thermo Scientific Model 42i-HL</td>
			<td></td>
		</tr>
	</tbody>
</table>

the effect of interfacial chemical bonding in tio2-sio2 composites on their photocatalytic nox abatement performance

颗粒状光催化剂与支撑材料表面的化学键合在设计更有效和更实用的光催化结构中是非常重要的。然而，这种化学键合对光催化剂的光学和表面性质以及因此其光催化活性/反应选择性行为的影响尚未得到系统的研究。在本研究中，TiO 2通过两种不同的方法被支撑在SiO 2的表面上:（i）通过使用四丁基正钛的溶胶 - 凝胶法（TBOT）在砂石英存在下原位形成TiO 2 ）;和（ii）通过将石英与四乙基原硅酸盐（TEOS）的反应形成的表面硅胶层上的商业TiO 2粉末结合到石英上。为了比较，TiO 2纳米颗粒也沉积在由a制备的更具反应性的SiO 2的表面上水解控制的溶胶 - 凝胶技术，以及通过TiO 2和SiO 2前体的溶胶 - 凝胶途径。通过FTIR光谱证实了通过界面Ti-O-Si键的TiO 2和SiO 2的组合，并且根据ISO标准方法（ISO 22197-1）测试所得复合材料的光催化降解NO的光催化降解， 。所得材料的电子显微镜图像显示，可以成功实现支撑体表面的可变光催化剂覆盖，但发现对NO去除的光催化活性受制备方法的影响，硝酸盐选择性受Ti-O-Si结合。

X射线衍射（XRD） 未涂覆石英砂（Q）的XRD图，制备的TiO 2 -SiO 2复合材料和不含石英的TiO 2 如图2所示。除了在400℃（QT1）下的制备，其中没有观察到清晰的TiO 2峰，峰位置证实在仅TiO 2样品以及TiO 2 -SiO 2复合材料中存在锐钛矿。在其他情况下，峰值强度和宽度之间的不同样品之间的差异是由于粒度和结晶度的差异。对于QT1，缺乏TiO 2峰可归因于在这些制备条件下负载在石英上的低结晶度或非常低量的TiO 2 。然而，透射电子显微镜（ 图3 ）显示了QT1用纳米颗粒TiO 2颗粒进行装饰，其在高倍放大下显示为聚集的纳米球。 <img alt="图2" class="xfigimg" src="/files/ftp_upload/56070/56070fig2.jpg" /> 图2: 不同方法制备的纯TiO 2和TiO 2 -SiO 2复合材料的XRD 图 。 <a href="http://ecsource.jove.com/files/ftp_upload/56070/56070fig2large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> <img alt="图3" class="xfigimg" src="/files/ftp_upload/56070/56070fig3.jpg" /> 图3: 二氧化钛涂覆的SiO 2样品的TEM图像; （a） QT1 （b） QT2和（c） ST1在低（1）和高（2）放大镜<html>阳离子图像。 <a href="http://ecsource.jove.com/files/ftp_upload/56070/56070fig3large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> 漫反射光谱 图4显示了作为间接半导体所需的入射光子能量的函数绘制的表示为修改的Kubelka-Munk函数[F（ R∞ ）hν] 1/2的制备样品的UV-vis吸收光谱。光谱也与TiO 2的存在一致，并且表明在SiO 2表面上的TiO 2负载对带隙具有可忽略的影响。然而，对于表示带隙扩大效应的混合氧化物样品（ST2），观察到向较高能级（约3.3eV）的小转变。 tp_upload / 56070 / 56070fig4.jpg"/&gt; 图4: TiO 2和TiO 2 -SiO 2复合材料的变形漫反射光谱（Tauc图）。 <a href="http://ecsource.jove.com/files/ftp_upload/56070/56070fig4large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> 傅里叶变换红外光谱（FTIR） 图5显示了SiO 2 / TiO 2混合氧化物样品和TiO 2 -Q复合材料的FTIR光谱。可以在可分配给Si-O-Ti伸缩振动模式15的 900 - 960 cm -1范围内观察到TiO 2与SiO 2的化学结合的证据;如预期的那样，对于SiO 2或TiO 2 ，没有观察到由于该模式的吸收峰。 图5: 用TiO 2 （ST1），SiO 2 -TiO 2混合氧化物（ST2），石英（Q）和TiO 2制备的TiO 2 （T1），SiO 2 ，活性二氧化硅改性石英样品（QT1，QT2） 。为了清楚起见，T2的频谱未示出，但与T1相同。 <a href="http://ecsource.jove.com/files/ftp_upload/56070/56070fig5large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> TiO 2 -石英复合材料 虽然Tokarsky 等人的分子模拟16表明Ti-O-Si在石英砂上的可能性，他们不能在实验上观察到Ti-O-Si在热水解后的明显证据在石英存在下硫酸氧钛。然而，从图5可以看出，在本研究中可比较的QT1复合材料表明少量的Ti-O-Si键合，在920-960cm -1范围内可以注意到非常低的IR吸收。 QT2表现出更显着的吸光度，可能与TiO 2与更具反应性的TEOS的相互作用与石英表面的相互作用相关。 TiO 2可能与所得的硅酸盐基凝胶而不是石英表面相关联。 混合氧化物系统 从有机前体的反应得出ST2测定本研究中测得的最高FTIR吸收。预期这样的系统将使与FTIR数据一致的反应物的分散和混合最大化。 ST1使用预沉淀二氧化硅，但尽管其反应性表面，所得到的FTIR吸收i表明粘结程度相对较低。 扫描电子显微镜（SEM） SEM研究了硅酸盐基薄膜在石英（QT2）上有效支撑TiO 2的有效性。这在很大程度上取决于胶片本身涂覆石英衬底的程度。 图6比较了在TEOS中分散的TiO 2 （PC105）中TiO 2以1:1摩尔比（QT2）分散的商业TiO 2 （PC105）的SEM-EDS。发现硅酸盐膜已经固定在颗粒上，因为一些区域保持不透过硅酸盐涂层。因此，在这种情况下，与硅酸盐系凝胶相相关的TiO 2也不均匀分布，并且不直接与石英表面接合。这与图 3b（2）中的TEM图像一致。硅酸盐涂层（图像右上角）给出了EDS分析与图6 （d）中报道的相当，表明TiO 2与硅酸盐层的缔合。 <img alt="图6" class="xfigimg" src="/files/ftp_upload/56070/56070fig6.jpg" /> 图6: （a）裸石英和（b）样品QT2的SEM图像。相应的EDS数据分别在c和d中给出。 <a href="http://ecsource.jove.com/files/ftp_upload/56070/56070fig6large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> 光催化性能 图7显示了在黑暗和病态下TiO 2 （PC105）中气流中NO，NO x和NO 2浓度变化的例子umination。当光线接通时，初始NO浓度下降约48％同时形成NO 2 。因此，在照明时间内，主要表示NO和NO 2浓度之和的NOx浓度降低。 NO在其照射TiO 2基光催化剂吸附后的转化途径可概括如下: NO→HONO→NO 2 →HONO 2 （NO 3 - ） 从图7还可以看出，在整个照射时间内NO的浓度略有增加。这说明了稳态条件的一种方法，可以归因于可用性的积累e光催化产生的NO氧化产物的活性位点， 即 HNO 2 / NO 2 - ; NO 2 ;和HNO 3 / NO 3 - ，这可能影响NO吸附速率。 Bloh等人报道说，在这个系统中实现稳态需要几个小时的照明。 <img alt="图7" class="xfigimg" src="/files/ftp_upload/56070/56070fig7.jpg" /> 图7:作为时间函数的NO，NO 2和NO x的浓度变化: （a）没有任何光催化剂或载体（b）仅石英，和（c） PC105。 <a href="http://ecsource.jove.com/files/ftp_upload/56070/56070fig7large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> 确定并比较所得TiO的活性<sub&gt; 2 -SiO 2复合材料用于NOx排除， 图8中计算并示出了去除NO，NO x和NO 2的光子效率（ξ）。 <img alt="图8" class="xfigimg" src="/files/ftp_upload/56070/56070fig8.jpg" /> 图8: 不同TiO 2和TiO 2 -SiO 2复合粉末对NO和NO x去除和NO 2形成的光子效率。直接比较的系统用相同的符号标识，支持的和不支持的对。 <a href="http://ecsource.jove.com/files/ftp_upload/56070/56070fig8large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> ξ定义为反应速率与入射光子通量的比值，为c根据等式（9） 18计算 ，其中<img alt="公式1" src="/files/ftp_upload/56070/56070eq1v2.jpg" />是体积流量; c在黑暗条件下NO，NO x或NO 2的浓度; c照明下相同气体的浓度;压力;阿阿格莫德罗常数h是Plank常数; c是光速; I为入射照射强度，λ为采用波长假设为单色光（365nm），A为照射面积; R气体常数;和T的绝对温度。 <img alt="方程式2" src="/files/ftp_upload/56070/56070eq2.jpg" /> （9）

Watch this Scientific Journal Video about The Effect of Interfacial Chemical Bonding in TiO2-SiO2 Composites on Their Photocatalytic NOx Abatement Performance at JoVE.com

The Effect of Interfacial Chemical Bonding in TiO2-SiO2 Composites on Their Photocatalytic NOx Abatement Performance

界面化学键合在TiO中的作用<sub&gt; 2</sub&gt; -SiO<sub&gt; 2</sub&gt;复合材料对其光催化NOx消除性能的影响

本工作的重点是建立产生和定量Ti-O-Si键的水平的手段，并将其与载体TiO 2的光催化性能相关联。

The chemical bonding of particulate photocatalysts to supporting material surfaces is of great importance in engineering more efficient and practical ...

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The Effect of Interfacial Chemical Bonding in TiO2-SiO2 Composites on Their Photocatalytic NOx Abatement Performance

Unit 1

Covalent Bonding and Structure

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13.2K 次观看.  University of Aberdeen. 本工作的重点是建立产生和定量Ti-O-Si键的水平的手段，并将其与载体TiO 2的光催化性能相关联。 

视频: The Effect of Interfacial Chemical Bonding in TiO2-SiO2 Composites on Their Photocatalytic NOx Abatement Performance

Manufacturing of Three-dimensionally Microstructured Nanocomposites through Microfluidic Infiltration

Microstructured composite beams reinforced with complex three-dimensionally (3D) patterned nanocomposite microfilaments are fabricated via nanocomposite in&#64257;ltration of 3D interconnected microfluidic networks. The manufacturing of the reinforced beams begins with the fabrication of microfluidic networks, which involves layer-by-layer deposition of fugitive ink filaments using a dispensing robot, filling the empty space between filaments using a low viscosity resin, curing the resin and finally removing the ink.&#160;Self-supported 3D structures with other geometries and many layers (e.g.&#160;a few hundreds layers) could be built using this method. The resulting tubular micro&#64258;uidic networks are then infiltrated with thermosetting nanocomposite suspensions containing nanofillers (e.g.&#160;single-walled carbon nanotubes), and subsequently cured. The infiltration is done by applying a pressure gradient between two ends of the empty network (either by applying a vacuum or vacuum-assisted microinjection). Prior to the infiltration, the nanocomposite suspensions are prepared by dispersing nanofillers into polymer matrices using ultrasonication and three-roll mixing methods. The nanocomposites (i.e.&#160;materials infiltrated) are then solidified under UV exposure/heat cure, resulting in a 3D-reinforced composite structure. The technique presented here enables the design of functional nanocomposite macroscopic products for microengineering applications such as actuators and sensors.

Three-dimensional (3D) microstructured composite beams are fabricated through the directed and localized infiltration of nanocomposites into 3D porous microfluidic networks. The flexibility of this manufacturing method enables the utilization of different thermosetting materials and nanofillers in order to achieve a variety of functional 3D reinforced nanocomposite macroscopic products.

通过微流体渗透制备三维微结构纳米复合材料的制造

Microstructured composite beams reinforced with complex three-dimensionally (3D) patterned nanocomposite microfilaments are fabricated via nanocomposite ...

科研

化学

Preparation of Highly Porous Coordination Polymer Coatings on Macroporous Polymer Monoliths for Enhanced Enrichment of Phosphopeptides

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous polymer monoliths. The developed approach is based on the preparation of a macroporous polymer containing carboxylic acid functional groups and the subsequent step-by-step solution-based controlled growth of a layer of a porous coordination polymer on the surface of the pores of the polymer monolith. The prepared metal-organic polymer hybrid has a high specific micropore surface area. The amount of iron(III) sites is enhanced through metal-organic coordination on the surface of the pores of the functional polymer support. The increase of metal sites is related to the number of iterations of the coating process.
The developed preparation scheme is easily adapted to a capillary column format. The functional porous polymer is prepared as a self-contained single-block porous monolith within the capillary, yielding a flow-through separation device with excellent flow permeability and modest back-pressure. The metal-organic polymer hybrid column showed excellent performance for the enrichment of phosphopeptides from digested proteins and their subsequent detection using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The presented experimental protocol is highly versatile, and can be easily implemented to different organic polymer supports and coatings with a plethora of porous coordination polymers and metal-organic frameworks for multiple purification and/or separation applications.

A procedure for the preparation of porous hybrid separation media composed of a macroporous polymer monolith internally coated by a high surface area microporous coordination polymer is presented.

对磷酸增强富集制备高度多孔配位聚合物涂层的孔聚合物石柱的

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous ...

Epitaxial Growth of Perovskite Strontium Titanate on Germanium via Atomic Layer Deposition

Atomic layer deposition (ALD) is a commercially utilized deposition method for electronic materials. ALD growth of thin films offers thickness control and conformality by taking advantage of self-limiting reactions between vapor-phase precursors and the growing film. Perovskite oxides present potential for next-generation electronic materials, but to-date have mostly been deposited by physical methods. This work outlines a method for depositing SrTiO3 (STO) on germanium using ALD. Germanium has higher carrier mobilities than silicon and therefore offers an alternative semiconductor material with faster device operation. This method takes advantage of the instability of germanium's native oxide by using thermal deoxidation to clean and reconstruct the Ge (001) surface to the 2&#215;1 structure. 2-nm thick, amorphous STO is then deposited by ALD. The STO film is annealed under ultra-high vacuum and crystallizes on the reconstructed Ge surface. Reflection high-energy electron diffraction (RHEED) is used during this annealing step to monitor the STO crystallization. The thin, crystalline layer of STO acts as a template for subsequent growth of STO that is crystalline as-grown, as confirmed by RHEED. In situ X-ray photoelectron spectroscopy is used to verify film stoichiometry before and after the annealing step, as well as after subsequent STO growth. This procedure provides framework for additional perovskite oxides to be deposited on semiconductors via chemical methods in addition to the integration of more sophisticated heterostructures already achievable by physical methods.

This work details the procedures for the growth and characterization of crystalline SrTiO3 directly on germanium substrates by atomic layer deposition. The procedure illustrates the ability of an all-chemical growth method to integrate oxides monolithically onto semiconductors for metal-oxide semiconductor devices.

锗通过原子层沉积钙钛矿型钛酸锶的外延生长

Atomic layer deposition (ALD) is a commercially utilized deposition method for electronic materials. ALD growth of thin films offers thickness control and ...

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding

Herein, we demonstrate that a bottom-up approach, based on halogen bonding (XB), can be successfully applied for the design of a new type of ionic liquid crystals (ILCs). Taking advantages of the high specificity of XB for haloperfluorocarbons and the ability of anions to act as XB-acceptors, we obtained supramolecular complexes based on 1-alkyl-3-methylimidazolium iodides and iodoperfluorocarbons, overcoming the well-known immiscibility between hydrocarbons (HCs) and perfluorocarbons (PFCs). The high directionality of the XB combined with the fluorophobic effect, allowed us to obtain enantiotropic liquid crystals where a rigid, non-aromatic, XB supramolecular anion acts as mesogenic core.
X-ray structure analysis of the complex between 1-ethyl-3-methylimidazolium iodide and iodoperfluorooctane showed the presence of a layered structure, which is a manifestation of the well-known tendency to segregation of perfluoroalkyl chains. This is consistent with the observation of smectic mesophases. Moreover, all the reported complexes melt below 100 &#176;C, and most are mesomorphic even at room temperature, despite that the starting materials were non-mesomorphic in nature.
The supramolecular strategy reported here provides new design principles for mesogen design allowing a totally new class of functional materials.

A protocol for the synthesis of a new type of mesogens, based on the halogen-bonded supramolecular anion [CnF2n+1-I&#183;&#183;&#183;I&#183;&#183;&#183;I-CnF2n+1]&#8722;, is reported.

从分子到材料: 通过卤素键合工程新的离子液体晶体

Herein, we demonstrate that a bottom-up approach, based on halogen bonding (XB), can be successfully applied for the design of a new type of ionic liquid ...

The Effect of Ultraviolet Radiation on the Chemical Bath Deposition of Bis(thiourea) Cadmium Chloride Crystals and the Subsequent CdS Obtention

In this work, the effects on the preparation of bis(thiourea) cadmium chloride crystals when illuminated with ultraviolet (UV) light at a wavelength of 367 nm using the chemical bath deposition technique are studied comparatively. Two experiments are performed to make a comparison: one without UV light and the other with the aid of UV light. Both experiments are performed under equal conditions, at a temperature of 343 K and with a pH of 3.2. The precursors used are cadmium chloride (CdCl2) and thiourea [CS(NH2)2], which are dissolved in 50 mL of deionized water with an acidic pH. In this experiment, the interaction of electromagnetic radiation is sought at the moment the chemical reaction is carried out. The results demonstrate the existence of an interaction between the crystals and the UV light; the UV light assistance causes crystal growths in an acicular shape. Also, the final product obtained is cadmium sulfide and shows no evident difference when synthesized with or without the use of UV light.

The Effect of Ultraviolet Radiation on the Chemical Bath Deposition of Bisthiourea Cadmium Chloride Crystals and the Subsequent CdS Obtention

This article presents a protocol for the synthesis of bis(thiourea) cadmium chloride crystals by chemical bath deposition. Two experiments are described: one aided by ultraviolet light compared to one without ultraviolet light.

紫外辐射对双 (硫脲) 氯化镉晶体化学镀液沉积的影响及随后的 CdS 获得

In this work, the effects on the preparation of bis(thiourea) cadmium chloride crystals when illuminated with ultraviolet (UV) light at a wavelength of ...

Extraction of Lignin with High &#946;-O-4 Content by Mild Ethanol Extraction and Its Effect on the Depolymerization Yield

Lignin valorization strategies are a key factor for achieving more economically competitive biorefineries based on lignocellulosic biomass. Most of the emerging elegant procedures to obtain specific aromatic products rely on the lignin substrate having a high content of the readily cleavable &#946;-O-4 linkage as present in the native lignin structure. This provides a miss-match with typical technical lignins that are highly degraded and therefore are low in &#946;-O-4 linkages. Therefore, the extraction yields, and the quality of the obtained lignin are of utmost importance to access new lignin valorization pathways. In this manuscript, a simple protocol is presented to obtain lignins with high &#946;-O-4 content by relatively mild ethanol extraction that can be applied to different lignocellulose sources. Furthermore, analysis procedures to determine the quality of the lignins are presented together with a depolymerization protocol that yields specific phenolic 2-arylmethyl-1,3-dioxolanes, which can be used to evaluate the obtained lignins. The presented results demonstrate the link between lignin quality and potential for the lignins to be depolymerized into specific monomeric aromatic chemicals. Overall, the extraction and depolymerization demonstrates a trade-off between the lignin extraction yield and the retention of the native aryl-ether structure and thus the potential of the lignin to be used as the substrate for the production of chemicals for higher-value applications.

Here, we present a protocol to perform ethanol extraction of lignin from several biomass sources. The effect of the extraction conditions on the lignin yield and &#946;-O-4 content are presented. Selective depolymerization is performed on the obtained lignins to obtain high aromatic monomer products.

轻度乙醇萃取高β-o-4 的木质素及其对解聚产率的影响

Lignin valorization strategies are a key factor for achieving more economically competitive biorefineries based on lignocellulosic biomass. Most of the ...

Synthesis of Soft Polysiloxane-urea Elastomers for Intraocular Lens Application

This study discusses a synthesis route for soft polysiloxane-based urea (PSU) elastomers for their applications as accommodating intraocular lenses (a-IOLs). Aminopropyl-terminated polydimethylsiloxanes (PDMS) were previously prepared via the ring-chain equilibration of the cyclic siloxane octamethylcyclotetrasiloxane (D4) and 1,3-bis(3-aminopropyl)-tetramethyldisiloxane (APTMDS). Phenyl groups were introduced into the siloxane backbone via the copolymerization of D4 and 2,4,6,8-tetramethyl-2,4,6,8-tetraphenyl-cyclotetrasiloxane (D4Me,Ph). These polydimethyl-methyl-phenyl-siloxane-block copolymers were synthesized for increasing the refractive indices of polysiloxanes. For applications as an a-IOL, the refractive index of the polysiloxanes must be equivalent to that of a young human eye lens. The polysiloxane molecular weight is controlled by the ratio of the cyclic siloxane to the endblocker APTMDS. The transparency of the PSU elastomers is examined by the transmittance measurement of films between 200 and 750 nm, using a UV-Vis spectrophotometer. Transmittance values at 750 nm (upper end of the visible spectrum) are plotted against the PDMS molecular weight, and &#62; 90% of the transmittance is observed until a molecular weight of 18,000 g&#183;mol&#8722;1. Mechanical properties of the PSU elastomers are investigated using stress-strain tests on die-cut dog-bone-shaped specimens. For evaluating mechanical stability, mechanical hysteresis is measured by repeatedly stretching (10x) the specimens to 5% and 100% elongation. Hysteresis considerably decreases with the increase in the PDMS molecular weight. In vitro cytotoxicity of some selected PSU elastomers is evaluated using an MTS cell viability assay. The methods described herein permit the synthesis of a soft, transparent, and noncytotoxic PSU elastomer with a refractive index approximately equal to that of a young human eye lens.

This study describes synthetic routes for aminopropyl-terminated polydimethylsiloxanes and polydimethyl-methyl-phenyl-siloxane-block copolymers and for soft polysiloxane-based urea (PSU) elastomers. It presents the application of PSUs as accommodating an intraocular lens. An evaluation method for in vitro cytotoxicity is also described.

软聚聚硅氧烷-尿素弹性体在人工晶体中的应用

This study discusses a synthesis route for soft polysiloxane-based urea (PSU) elastomers for their applications as accommodating intraocular lenses ...

A Continuous-flow Photocatalytic Reactor for the Precisely Controlled Deposition of Metallic Nanoparticles

In this work, a novel photocatalytic reactor for the pulsed and controlled excitation of the photocatalyst and the precise deposition of metallic nanoparticles is developed. Guidelines for the replication of the reactor and its operation are provided in detail. Three different composite systems (Pt/graphene, Pt/TiO2, and Au/TiO2) with monodisperse and uniformly distributed particles are produced by this reactor, and the photodeposition mechanism, as well as the synthesis optimization strategy, are discussed. The synthesis methods and their technical aspects are described comprehensively. The role of the ultraviolet (UV) dose (in each excitation pulse) on the photodeposition process is investigated and the optimum values for each composite system are provided.

For a continuous and scalable synthesis of noble-metal-based nanocomposites, a novel photocatalytic reactor is developed and its structure, operation principles, and product quality optimization strategies are described.

一种用于金属纳米粒子精确控制沉积的连续流动光催化反应器

In this work, a novel photocatalytic reactor for the pulsed and controlled excitation of the photocatalyst and the precise deposition of metallic ...

Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method

The single deuterium substitution in porphycene leads to an asymmetric molecular geometry, which may affect the double proton transfer process in the porphycene molecule. In this study, we applied an enhanced QM/MM method called SITS-QM/MM to investigate hydrogen/deuterium (H/D) isotope effects on the double proton transfer in porphycene. Distance changes in SITS-QM/MM molecular dynamics simulations suggested that the deuterium substituted porphycene adopted the stepwise double proton transfer mechanism. The structural analysis and the free energy shifts of double proton transfer process indicated that the asymmetric isotopic substitution subtly compressed the covalent hydrogen bonds and may alter the original transition state location.

A protocol that uses enhanced QM/MM method to investigate the isotopic effect on the double proton transfer process in porphycene is presented here.

增强QM/MM方法研究的植物双质子转移过程中的同位素效应

The single deuterium substitution in porphycene leads to an asymmetric molecular geometry, which may affect the double proton transfer process in the ...

Synthesis of Information-bearing Peptoids and their Sequence-directed Dynamic Covalent Self-assembly

This protocol presents the use of Lewis acidic multi-role reagents to circumvent kinetic trapping observed during the self-assembly of information-encoded oligomeric strands mediated by paired dynamic covalent interactions in a manner mimicking the thermal cycling commonly employed for the self-assembly of complementary nucleic acid sequences. Primary amine monomers bearing aldehyde and amine pendant moieties are functionalized with orthogonal protecting groups for use as dynamic covalent reactant pairs. Using a modified automated peptide synthesizer, the primary amine monomers are encoded into oligo(peptoid) strands through solid-phase submonomer synthesis. Upon purification by high-performance liquid chromatography (HPLC) and characterization by electrospray ionization mass spectrometry (ESI-MS), sequence-specific oligomers are subjected to high-loading of a Lewis acidic rare-earth metal triflate which both deprotects the aldehyde moieties and affects the reactant pair equilibrium such that strands completely dissociate. Subsequently, a fraction of the Lewis acid is extracted, enabling annealing of complementary sequence-specific strands to form information-encoded molecular ladders characterized by matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS). The simple procedure outlined in this report circumvents kinetic traps commonly experienced in the field of dynamic covalent assembly and serves as a platform for the future design of robust, complex architectures.

A protocol is presented for the synthesis of information-encoded peptoid oligomers and for the sequence-directed self-assembly of these peptoids into molecular ladders using amines and aldehydes as dynamic covalent reactant pairs and Lewis acidic rare-earth metal triflates as multi-role reagents.

信息承载Peptoids及其序列定向动态共价自组装的合成

This protocol presents the use of Lewis acidic multi-role reagents to circumvent kinetic trapping observed during the self-assembly of information-encoded ...