直接甲酸燃料电池炭载Pd阳极催化剂的稳定性

用X射线衍射和电化学方法研究了在甲酸溶液中浸泡一段时间后的Pd/C催化剂的结构和电催化性能, 发现在甲酸溶液中浸泡15 d后, Pd/C催化剂中Pd粒子的相对结晶度由1.73增加到3.34, 平均粒径由4.4 nm降低到1.8 nm, 对甲酸氧化的电催化活性和稳定性降低, 甲酸氧化的峰电流密度由9.3 mA/cm2降低到6.7 mA/cm2. 这可能是由Pd/C催化剂中的Pd在甲酸中会有一定的溶解和Pd/C催化剂能催化分解甲酸引起的.     

直接甲酸燃料电池Pd阳极催化剂及其电催化稳定性

直接甲酸燃料电池(DFAFC)中Pd阳极催化剂对甲酸氧化具有很好的电催化活性, 但电催化稳定性较差, 因此, 对Pd催化剂电催化活性和稳定性的影响原因和机理的研究已经成为DFAFC阳极催化剂的研究重点, 本文综述了DFAFC中Pd催化剂和Pd基复合催化剂的研究和发展概况. 主要介绍了Pd催化剂的优缺点、稳定性及提高稳定性的方法和机理等, 为Pd催化剂和Pd基复合催化剂的实际应用奠定基础.     

A Direct Formaldehyde Fuel Cell for CO2-Emission Free Co-generation of Electrical Energy and Valuable Chemical/Hydrogen

Converting carbon-based molecular fuels into electricity efficiently and cleanly without emitting CO₂ remains a challenge. Conventional fuel cells using noble metals as anode catalysts often suffer performance degradation due to CO poisoning and a host of problems associated with CO₂ production. This study provides a CO₂-emission-free direct formaldehyde fuel cell. It enables a flow of electricity while producing H₂ and valuable formate. Unlike conventional carbon-based molecules electrooxidation, formaldehyde 1-electron oxidation is performed on the Cu anode with high selectivity, thus generating formate and H₂ without undergoing CO₂ pathway. In addition, the fuel cell produces 0.62 Nm³ H₂ and 53 mol formate per 1 kWh of electricity generated, with an open circuit voltage of up to 1 V and a peak power density of 350 mW cm⁻². This study puts forward a zero-carbon solution for the efficient utilization of carbon-based molecule fuels that generates electricity, hydrogen and valuable chemicals in synchronization.     

Facile Synthesis of Carbon‐Supported Ultrasmall Ag@Pd Core‐Shell Nanocrystals with Superior Electrocatalytic Activity for Direct Formic Acid Fuel Cell Application

To design electrocatalysts with excellent performance, morphology, composition and structure is a decisive influential factor. In this work, ultrasmall Ag@Pd core‐shell nanocrystals supported on Vulcan XC72R carbon with different Ag/Pd atomic ratios are synthesized via a facile successive reduction approach with formaldehyde and ethylene glycol as reducing agents, respectively. The Ag‐core/Pd‐shell nanostructures are revealed by high‐resolution transmission electron microscopy (HRTEM). Ag@Pd core‐shell nanocrystals possess a narrow size distribution with an average size of ca. 4.3 nm. In comparison to monometallic Pd/C and commercial Pd black catalysts, such Ag@Pd core‐shell nanocrystals display excellent electrocatalytic activities for formic acid oxidation, which may be due to high Pd utilization derived from the formation of Ag@Pd core‐shell nanostructure and the strong interaction between Ag and Pd.     

High Loading Pt Core/Carbon Shell Derived from Platinum‐Aniline Complex for Direct Methanol Fuel Cell Application

A novel approach to high loaded Pt core/carbon shell catalyst synthesis from a Pt‐aniline complex was reported. The Pt‐aniline complex was successfully synthesized by irradiating an ultrasound to the hexachloro platinic acid and aniline monomer mixture. The highly viscous nature of aniline leads to reproducible hexagonal plate like Pt‐aniline complex crystals. The chemical composition of the Pt‐aniline complex was identified as [PtCl₂(C₆H₅NH₂)₂] with the help of NMR, XPS, HR ESI‐MS, and TGA analyses. Furthermore, the Pt‐aniline hexagonal plates were sintered at various temperatures like 400 °C, 500 °C, and 700 °C for an hour. This formed the highly dispersed carbon covered Pt nano particles with loading of 80.1 wt %, 81.3 wt %, and 83.4 wt % for HP‐4, HP‐5, and HP‐7, respectively. After supporting it on Vulcan XC‐72, Pt core/carbon shell pyrolyzed at a low temperature showed excellent performance in methanol oxidation reaction. In addition, Pt core/carbon shell prepared at a high temperature revealed excellent tolerance to methanol.