基于三维结构的钯催化电极的制备及其性能分析

Fabrication and Performance Analysis of Palladium Catalytic Electrodes Based on a 3D Structure

利用MEMS技术制备了硅微通道板（Si-MCP）并以此作为基底制备宏孔导电网络（MECN）,利用3种方式在其外表面和孔道内壁沉积钯纳米粒子合成了三维乙醇催化电极。通过X射线衍射（XRD）和扫描电子显微镜（SEM）等表征手段对电极形貌和组分进行了分析,基于液流沉积的样品孔道内壁的钯纳米粒子最为均匀和致密。电化学测试结果也表明此种样品具有最优的电催化活性和运行稳定性（连续扫描后,催化电流仅下降11%）。其中,液流沉积形成的样品对高浓度乙醇的电催化氧化电流密度可达554 mA/cm2,此数值分别是真空无电镀样品产生的电流密度的3.5倍,电镀样品产生的电流密度的35倍。研究结果说明,液流沉积形成的丰富活性位点有助于提高三维微型催化电极的电化学性能,因此基于液流沉积的Pd/MECN电极将在乙醇燃料电池方面具有广阔的应用前景。

A silicon micro-channel plate（Si-MCP）was prepared by MEMS techniques and then was used as the substrate to fabricate a macroporous electrically conductive network（MECN）.Palladium nanoparticles were deposited onto the outer surface and the channel inner walls of the MECN by three kinds of the deposition techniques to synthesize the 3D catalytic electrodes for ethanol.The morphology and composition of the electrodes were analyzed by X-ray diffraction（XRD）and scanning electron microscope（SEM）.The results show that the palladium nanoparticles on the channel inner walls of the sample prepared by liquid flow deposition are the most uniform and compact.The electrochemical test result also shows that the samples exhibit the most excellent electrocatalytic activity and operational stability（only 11% loss of the catalytic current after continuous scanning）.The electrocatalytic oxidation current density of the samples based on the liquid flow deposition technique towards high concentration of ethanol can reach 554 mA/cm^2,which is 3.5 times that of the sample adopted the vacuum electroless deposition and 35 times that of the sample adopted the electrodeposition,respectively.The research results show that the abundant active sites fabricated by the liquid flow deposition are beneficial to improve the electrochemical performances of the 3D micro catalytic electrodes.Therefore,the Pd/MECN electrode based on the liquid flow deposition will have a broad application prospect in ethanol fuel cells.