摘要/Abstract
微/纳多孔金属材料具有高比表面积等优点，在电化学等领域广受关注.本工作通过动态氢气泡模板法，在镀金玻璃碳电极（Aupla/GCE）上电沉积三维蜂窝状多孔纳米AuPtCu （3DHPN-AuPtCu）复合材料，再阳极溶出Cu，制备了3DHPN-AuPtCu/Aupla/GCE.采用循环伏安法（CV）、金相显微镜、扫描电子显微镜、能量色散谱和电感耦合等离子体-原子发射光谱等手段表征了相关修饰电极.所制3DHPN-AuPtCu/Aupla/GCE在含0.2 mol/L HCOOH的0.5 mol/L H2SO4水溶液中，电催化氧化甲酸的峰电流密度为12.5 mA·cmPt-2（CV，-0.3～1.0 V，50 mV/s），优于有关对照电极和很多已报道的Pt复合物修饰电极，表明通过这种动态氢气泡/牺牲铜双模板法可制备出电催化性能优异的金属蜂窝结构.
关键词: 动态氢气泡模板, 牺牲铜模板, 蜂窝结构AuPtCu电催化剂, 甲酸氧化
Improving the performance of electrocatalytic formic acid oxidation is the key issue to develop high-performance direct formic acid fuel cells (DFAFC). Pt-based and Pd-based materials are the important electrocatalysts for formic acid oxidation. Micro/nano-porous metal materials are widely concerned in the electrochemistry field due to the high specific electrode-surface area. The dynamic hydrogen bubble template (DHBT) method has been widely used for preparing the three-dimensional honeycomb-like porous nano-metals (3DHPNMs). However, as far as we know, the use of a sacrificial metal template to prepare the 3DHPNMs with improved performance for the electrocatalytic oxidation of small organic molecules has not been reported. Herein, a three-dimensional honeycomb-like porous nano-AuPtCu (3DHPN-AuPtCu) composite was electrodeposited on a gold-plated glassy carbon electrode (Aupla/GCE) by the DHBT method, followed by anodic stripping of Cu to yield a 3DHPN-AuPtCu/Aupla/GCE. The relevant modified electrodes were characterized by cyclic voltammetry (CV), metallographic microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy and inductively coupled plasma-atomic emission spectrometry. The SEM results clearly revealed that the use of the sacrificial Cu template can modulate the metal-honeycomb structure, and the 3DHPN-AuPtCu/Aupla/GCE can thus possess the better micro/nano-porous structure and the improved electrocatalytic performance than a Cu-template-free 3DHPN-AuPt/Aupla/GCE. In our opinion, the simultaneous electrodeposition of Cu can intervene in the electrodeposition of Au and Pt, and thus a new structure with more active sites exposed and the electrocatalysis performance improved can be obtained after the anodic stripping of electrodeposited Cu. As a result, the 3DHPN-AuPtCu/Aupla/GCE exhibited high anti-poisoning nature and high stability, because many discontinuous Pt atoms on this electrode can suppress the formation of adsorption-state COads during the electrocatalytic oxidation of formic acid. The electrocatalytic oxidation peak current density on 3DHPN-AuPtCu/Aupla/GCE in 0.5 mol/L aqueous H2SO4 containing 0.2 mol/L HCOOH was 12.5 mA·cmPt-2 (CV, -0.3~1.0 V, 50 mV/s), which is superior to the control electrodes and many reported Pt-based electrocatalysis electrodes. The suggested double- template method for preparing honeycomb-structured micro/nano-porous metal materials with improved performance has the potential for wider electrocatalysis and electroanalysis applications.
Key words: dynamic hydrogen bubble template, sacrificial Cu template, honeycomb-structured AuPtCu electrocatalyst, formic acid oxidation
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