This work was supported by the National Key Technologies R&#38;D Program of China (2021YFA0715302 and 2021YFE0191800), the National Natural Science Foundation of China (61975035 and 52150610489), and the Science and Technology Commission of Shanghai Municipality (22ZR1405000).

1. Pre-processing of materials
NOTE: Ni-foam (commercially available, see Table of Materials) with 25 mm x 25 mm x 1.5 mm is used for the H2O2 FC&#39;s anode.
<ol>
	<li>Immerse the Ni-foam sample into alcohol and deionized (DI) water, sonicate for three times, 5 min in solvent and water. Subsequently, place the Ni-foam on a clean glass substrate.</li>
	<li>Utilize the carbon fiber cloth (see Table of Materials) as the c...

Exploring Innovative 3D Electrodes for Hydrogen Peroxide Fuel Cells

<ol>
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S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogen+fuel+and+fuel+cell+technology+for+cleaner+future:+a+review.">Hydrogen fuel and fuel cell technology for cleaner future: a review.</a> Environmental Science and Pollution Research International. 28 (13), 15607-15626 (2021).</li><li>Cao, D., Chen, D., Lan, J., Wang, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+alkaline+direct+NaBH4-H2O2+fuel+cell+with+high+power+density.">An alkaline direct NaBH4-H2O2 fuel cell with high power density.</a> Journal of Power Sources. 190 (2), 346-350 (2009).</li><li>Lan, R., Tao, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ammonia+as+a+suitable+fuel+for+fuel+cells.">Ammonia as a suitable fuel for fuel cells.</a> Frontiers in Energy Research. 2, 2014 (2014).</li><li>Alias, M. S., Kamarudin, S. K., Zainoodin, A. M., Masdar, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Active+direct+methanol+fuel+cell:+An+overview.">Active direct methanol fuel cell: An overview.</a> International Journal of Hydrogen Energy. 45 (38), 19620-19641 (2020).</li><li>Ferrigno, R., Stroock, A. D., Clark, T. D., Mayer, M., Whitesides, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Membraneless+vanadium+redox+fuel+cell+using+laminar+flow.">Membraneless vanadium redox fuel cell using laminar flow.</a> Journal of the American Chemical Society. 124 (44), 12930-12931 (2002).</li><li>Yan, X., Xu, A., Zeng, L., Gao, P., Zhao, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+paper-based+microfluidic+fuel+cell+with+hydrogen+peroxide+as+fuel+and+oxidant.">A paper-based microfluidic fuel cell with hydrogen peroxide as fuel and oxidant.</a> Energy Technology. 6 (1), 140-143 (2018).</li><li>Ha, S. M., Ahn, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laminar+flow-based+micro+fuel+cell+utilizing+grooved+electrode+surface.">Laminar flow-based micro fuel cell utilizing grooved electrode surface.</a> Journal of Power Sources. 267, 731-738 (2014).</li><li>Liu, Z., 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=A+woven+thread-based+microfluidic+fuel+cell+with+graphite+rod+electrodes.">A woven thread-based microfluidic fuel cell with graphite rod electrodes.</a> International Journal of Hydrogen Energy. 43 (49), 22467-22473 (2018).</li><li>Peng, J., Zhang, Z. Y., Niu, H. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Three-dimensional+two-phase+model+for+a+membraneless+fuel+cell+using+decomposition+of+hydrogen+peroxide+with+y-shaped+microchannel.">A Three-dimensional two-phase model for a membraneless fuel cell using decomposition of hydrogen peroxide with y-shaped microchannel.</a> Fuel Cells. 12 (6), 1009-1018 (2012).</li><li>Wu, K. H., 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=Highly+selective+hydrogen+peroxide+electrosynthesis+on+carbon:+in+situ+interface+engineering+with+surfactants.">Highly selective hydrogen peroxide electrosynthesis on carbon: in situ interface engineering with surfactants.</a> Chem. 6 (6), 1443-1458 (2020).</li><li>Yang, Y., 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=A+facile+microfluidic+hydrogen+peroxide+fuel+cell+with+high+performance:+electrode+interface+and+power-generation+properties.">A facile microfluidic hydrogen peroxide fuel cell with high performance: electrode interface and power-generation properties.</a> ACS Applied Energy Materials. 1 (10), 5328-5335 (2018).</li><li>An, L., Zhao, T., Yan, X., Zhou, X., Tan, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+dual+role+of+hydrogen+peroxide+in+fuel+cells.">The dual role of hydrogen peroxide in fuel cells.</a> Science Bulletin. 60 (1), 55-64 (2015).</li><li>Yamazaki, S. I., 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=A+fuel+cell+with+selective+electrocatalysts+using+hydrogen+peroxide+as+both+an+electron+acceptor+and+a+fuel.">A fuel cell with selective electrocatalysts using hydrogen peroxide as both an electron acceptor and a fuel.</a> Journal of Power Sources. 178 (1), 20-25 (2008).</li><li>Sanli, A. E., Ayta&#231;, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Response+to+Disselkamp:+Direct+peroxide/peroxide+fuel+cell+as+a+novel+type+fuel+cell.">Response to Disselkamp: Direct peroxide/peroxide fuel cell as a novel type fuel cell.</a> International Journal of Hydrogen Energy. 36 (1), 869-875 (2011).</li><li>Gu, L., Nie, L., George H, M. i. l. e. y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cathode+electrocatalyst+selection+and+deposition+for+a+direct+borohydride/hydrogen+peroxide+fuel+cell.">Cathode electrocatalyst selection and deposition for a direct borohydride/hydrogen peroxide fuel cell.</a> Journal of Power Sources. 173 (1), 77-85 (2007).</li><li>Yang, F., Cheng, K., Wu, T., Zhang, Y., Yin, J., Wang, G., Cao, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+of+Au+nanodendrites+supported+on+carbon+fiber+cloth+and+its+catalytic+performance+to+H2O2+electroreduction+and+electrooxidation.">Preparation of Au nanodendrites supported on carbon fiber cloth and its catalytic performance to H2O2 electroreduction and electrooxidation.</a> RSC Advances. 3 (16), 5483-5490 (2013).</li><li>Vidal-Iglesias, F. J., Solla-Gull&#243;n, J., Herrero, E., Rodes, A., Aldaz, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Do+you+really+understand+the+electrochemical+Nernst+equation.">Do you really understand the electrochemical Nernst equation.</a> Electrocatalysis. 4, 1-9 (2013).</li><li>Jing, X., 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=The+open+circuit+potential+of+hydrogen+peroxide+at+noble+and+glassy+carbon+electrodes+in+acidic+and+basic+electrolytes.">The open circuit potential of hydrogen peroxide at noble and glassy carbon electrodes in acidic and basic electrolytes.</a> Journal of Electroanalytical Chemistry. 658 (1-2), 46-51 (2011).</li><li>Eaves, S., Eaves, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+cost+comparison+of+fuel-cell+and+battery+electric+vehicles.">A cost comparison of fuel-cell and battery electric vehicles.</a> Journal of Power Sources. 130 (1-2), 208-212 (2004).</li><li>Wee, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Which+type+of+fuel+cell+is+more+competitive+for+portable+application:+Direct+methanol+fuel+cells+or+direct+borohydride+fuel+cells.">Which type of fuel cell is more competitive for portable application: Direct methanol fuel cells or direct borohydride fuel cells.</a> Journal of Power Sources. 161 (1), 1-10 (2006).</li><li>Muthukumar, P., Groll, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Erratum+to+&amp;#34;Metal+hydride+based+heating+and+cooling+systems:+a+review&amp;#34.">Erratum to &amp;#34;Metal hydride based heating and cooling systems: a review&amp;#34.</a> International Journal of Hydrogen Energy. 35 (16), 8816-8829 (2010).</li></ol>

Several parameters significantly influence the performance of a membraneless hydrogen peroxide fuel cell beyond solution pH and H2O2 concentration. The choice of electrode material dictates electrocatalytic activity and stability, while the electrode&#39;s surface area can enhance reaction sites. Operating temperature affects reaction kinetics, and the flow rate of reactants can determine the mixing efficiency of fuel and oxidant. The concentration of any catalyst used is pivotal for reaction rates,...

A fuel cell is an electrochemical device that utilizes fuel and oxidant to convert chemicals into electrical energy. FCs have higher energy conversion efficiency than traditional combustion engines since they are not bound by the Carnot Cycle1. By utilizing fuels such as hydrogen (H2)2, borohydride-hydrogen (NaBH4)3, and ammonia (NH3)4, FCs have become a promising energy source that is environmentally clean and can achieve high performance, offering significant potential to reduce human dependence on fossil fuels. However, FC technology faces specific challenges. One prevalent issue is the internal role of a proton exchange membrane (PEM) in the FC system, which acts as a safeguard against internal short circuits. The integration of an electrolytic membrane contributes to increased fabrication costs, internal circuit resistance, and architectural complexity5. Moreover, transforming single-compartment FCs into multi-stack arrays introduces additional complications due to the intricate process of integrating flow channels, electrodes, and plates to enhance power and current outputs5.
Over the past decades, concerted efforts have been made to address these membrane-related challenges and streamline the FC system. Notably, the emergence of membraneless FC configurations using laminar co-flows at low Reynold numbers has offered an innovative solution. In such setups, the interface between two flows functions as a &#34;virtual&#34; proton-conducting membrane6. Laminar flow-based FCs (LFFCs) have been widely studied, leveraging the benefits of microfluidics7,8,9,10. However, LFFCs require stringent conditions, including high energy input for pumping laminar fuels/oxidants, mitigation of reactant crossover in fluidic streams, and optimization of hydrodynamic parameters.
Recently, H2O2 has gained interest as a potential fuel and oxidant due to its carbon-neutral nature, yielding water (H2O) and oxygen (O2) during electrooxidation and electroreduction processes at electrodes11,12. H2O2 can be mass-produced using a two-electron reduction process or by a two-electron oxidation process from water12. Subsequently, in contrast to other gaseous fuels, liquid H2O2 fuel can be integrated into existing gasoline infrastructure 5. Besides, the H2O2 disproportionation reaction makes it possible to serve H2O2 as both fuel and oxidant. Figure 1A shows a schematic structure of a facile H2O2 FC&#39;s architecture. In comparison to traditional FCs2,3,4, the H2O2 FC utilizes the advantages of device &#34;simplicity.&#34; Yamasaki et al. demonstrated membraneless H2O2 FCs, playing the role of both fuel and oxidant. The described mechanism of electrical energy generation has inspired research communities to continue this research direction6. Subsequently, electrooxidation and electroreduction mechanisms using H2O2 as a fuel and oxidant have been represented by the following reactions13,14
In the acidic media:
Anode: H2O2 &#8594; O2 + 2H+ + 2e-; Ea1 = 0.68 V vs. SHE 
Cathode: H2O2 + 2H+ + 2e- &#8594; 2H2O; Ea2 = 1.77 V vs. SHE 
Total: 2 H2O2 &#8594; 2H2O + O2
In the basic media:
H2O2 + OH- &#8594; HO2- + H2O 
Anode: HO2- + OH- &#8594; O2 + H2O + 2e-; Eb1 = 0.15 V vs. SHE 
Cathode: HO2- + H2O + 2e- &#8594; 3OH-; Eb2 = 0.87 V vs. SHE 
Total: 2 H2O2 &#8594; 2H2O + O2
Figure 1B illustrates the working principle of H2O2 FCs. H2O2 donates electrons at the anode and accepts electrons at the cathode. Electron transfer between the anode and cathode occurs through an external circuit, resulting in the generation of electricity. The theoretical open circuit potential (OCP) of H2O2 FC is 1.09 V in acidic media and 0.62 V in basic media13. However, numerous experimental results have shown lower values, reaching up to 0.75 V in acidic media and 0.35 V in basic media, compared to the theoretical OCP. This observation can be attributed to the presence of a mixed potential13. Additionally, the power and current output of H2O2 FCs cannot compete with the mentioned FCs2,3,4due to the limited catalytic selectivity of the electrodes. Nevertheless, it is noteworthy that current H2O2 FC technology can outperform H2, NaBH4, and NH3 FCs in terms of overall cost, as shown in Table 1. Thus, the enhanced catalytic selectivity of electrodes for H2O2 electrooxidation and electroreduction remains a significant challenge for these devices.
In this study, we introduce a three-dimensional porous structure electrode to improve the interaction between the electrode and H2O2 fuel, aiming to increase the reaction rate and enhance power and current output. We also investigate the impact of solution pH and H2O2 concentration on the FC&#39;s performance. The electrode pair used in this study comprises a gold-electroplated carbon fiber cloth and nickel foam. Structural characterization is conducted using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), with Open Circuit Potential (OCP), polarization, and power output curves serving as the primary parameters for FC testing.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Acetone</td>
			<td>Merck &#38; Co. Inc. (MRK)</td>
			<td>67-64-1</td>
			<td>solution for pre-process of materials</td>
		</tr>
		<tr>
			<td>Alcohol</td>
			<td>Merck &#38; Co. Inc. (MRK)</td>
			<td>64-17-5</td>
			<td>solution for pre-process of materials</td>
		</tr>
		<tr>
			<td>Carbon fiber cloth</td>
			<td>Soochow Willtek photoelectric materials co.,Ltd.</td>
			<td>W0S1011</td>
			<td>substrate material for electroplating method</td>
		</tr>
		<tr>
			<td>Electrochemistry station</td>
			<td>&#160;Shanghai Chenhua Instrument Co., Ltd.</td>
			<td>CHI600E</td>
			<td>device for electroplating method and fuel cell performance characterization</td>
		</tr>
		<tr>
			<td>Gold chloride trihydrate</td>
			<td>Shanghai Aladdin Biochemical Technology Co.,Ltd.</td>
			<td>G141105-1g</td>
			<td>main solute for electroplating method</td>
		</tr>
		<tr>
			<td>Hydrochloric acid</td>
			<td>Sinopharm Chemical ReagentCo., Ltd</td>
			<td>10011018</td>
			<td>adjustment of solution pH</td>
		</tr>
		<tr>
			<td>Hydrogen peroxide</td>
			<td>Sinopharm Chemical ReagentCo., Ltd</td>
			<td>10011208</td>
			<td>fuel of cell</td>
		</tr>
		<tr>
			<td>Nickel foam</td>
			<td>Willtek photoelectric materials co.ltd(Soochow,China)</td>
			<td>KSH-2011</td>
			<td>anode material for hydrogen peroxide fuel cell</td>
		</tr>
		<tr>
			<td>Potassium chloride</td>
			<td>Shanghai Aladdin Biochemical Technology Co.,Ltd.</td>
			<td>10016308</td>
			<td>additives for electroplating method</td>
		</tr>
		<tr>
			<td>Scanning electron microscope</td>
			<td>Carl Zeiss AG</td>
			<td>EVO 10</td>
			<td>structural characterization for sample</td>
		</tr>
		<tr>
			<td>Sodium hydroxide</td>
			<td>Sinopharm Chemical ReagentCo., Ltd</td>
			<td>10019718</td>
			<td>adjustment of solution pH</td>
		</tr>
		<tr>
			<td>X-Ray differaction machine</td>
			<td>Bruker Corporation</td>
			<td>D8 Advance</td>
			<td>structural characterization for sample</td>
		</tr>
	</tbody>
</table>

membraneless hydrogen peroxide fuel cells as a promising clean energy source

In an in-depth investigation of membraneless hydrogen peroxide-based fuel cells (H2O2 FCs), hydrogen peroxide (H2O2), a carbon-neutral compound, is demonstrated to undergo electrochemical decomposition to produce H2O, O2, and electrical energy. The unique redox properties of H2O2 position it as a viable candidate for sustainable energy applications. The proposed membraneless design addresses the limitations of conventional fuel cells, including fabrication complexities and design challenges. A novel three-dimensional electrode, synthesized via electroplating techniques, is introduced. Constructed from Au-electroplated carbon fiber cloth combined with Ni-foam, this electrode showcases enhanced electrochemical reaction kinetics, leading to an increased power density for H2O2 FCs. The performance of fuel cells is intricately linked to the pH levels of the electrolyte solution. Beyond FC applications, such electrodes hold potential in portable energy systems and as high surface area catalysts. This study emphasizes the significance of electrode engineering in optimizing the potential of H2O2 as an environmentally friendly energy source.

Author Spotlight: Design and Evaluation of Au-Electroplated Carbon Fiber Cloth Electrodes for Hydrogen Peroxide Fuel Cells 

Membraneless Hydrogen Peroxide Fuel Cells as a Promising Clean Energy Source

We have illustrated a facial electroplating method deposit nano gold particles on the high surface area carbon cloth. The golds electroplate carbon cloth is heavy grid performance in serving as a cathode for hydrogen peroxide fuel cells. Due to the specific mechanism of membraneless hydrogen peroxide fuel cells, researchers are currently based on developing noble metal complexes as electrodes and improving the sensitive area of these electrodes by employing nanotechnology and coordination chemistry.In our research, we not only proposed the electroplating methods for fabrication high surface area for the electrodes, but also found a very important role of pH in fuel cell, which remains neglected in the previously reported research. There are a lot of techniques can be used for fabricating these nanoscale electrodes, such as physical or chemical evaporations. However, this methods are very expensive, as well as time consuming.As electrodes now need accuracy in thickness, electroplating is a very promising methods for these electrodes.

Electroplating results 
Figure 2&#160;shows the electroplating results. Figure 2A indicates the X-ray diffraction result. Figure 2B,C are the micrographs. Figure 2D,E are SEM results. The effective deposition of gold (Au) on the carbon fiber cloth (CF) was first confirmed using the physical change of color in the carbon fiber cloth from black to go...

Watch this Scientific Journal Video about Design and Evaluation of Au-Electroplated Carbon Fiber Cloth Electrodes for Hydrogen Peroxide Fuel Cells at JoVE.com

This protocol introduces the design and evaluation of innovative three-dimensional electrodes for hydrogen peroxide fuel cells, utilizing Au-electroplated carbon fiber cloth and Ni-foam electrodes. The research findings highlight hydrogen peroxide's potential as a promising candidate for sustainable energy technologies.

In an in-depth investigation of membraneless hydrogen peroxide-based fuel cells (H2O2 FCs), hydrogen peroxide (H2O2), a carbon-neutral compound, is ...

membraneless-hydrogen-peroxide-fuel-cells-as-promising-clean-energy