Pt-Ir共沉积电位对电解氨水制氢的性能影响

为研究在线电解氨水为氢燃料电池供氢的可行性,采用电化学共沉积法,在不同沉积条件下制备了PtIr催化电极,用循环伏安法(CV)与计时安培法(I-t)结合电镜、XPS和XRD结构分析,研究了电极对氨水的电解催化性能。结果表明,沉积电位影响了合金催化剂的组成、晶型、晶粒尺寸等,从而进一步影响了电极在氨催化过程中的性能。当沉积电位固定,电极上的催化剂负载量、氨水电解过程中催化剂的形貌、结构、组成基本稳定。其中,-0.05 V(vs. SCE)沉积电位下制备的催化剂在氨的电解催化过程中持续性和稳定性好,催化剂的负载量和过电位也最低。利用电化学上电解氨和生成水电位上的差异,将氨电解为燃料电池供氢,在低电流密度下(<10 mA/cm²)燃料电池为氨电解池提供能量的同时仍然有40%以上的额外功率用于其他负载。

Influences of Pt-Ir electro-codeposition potentials on hydrogen production with ammonia electrolysis

To study the feasibility of on-line electrolysis of ammonia water to provide hydrogen for hydrogen fuel cell, Pt-Ir catalyst was prepared by electrochemical co-deposition under different deposition conditions. Performance of Pt-Ir catalyst for ammonia electrolysis was studied by cyclic voltammetry (CV) and chronoamperometry (I-t) combined with SEM, XPS and XRD. The results show that the deposition potential affects the composition, crystal form, and grain size of the alloy catalyst, which further affects the performance of the electrode in the ammonia catalysis process. For a certain deposition potential, the morphology, structure and composition of the catalyst are stable in certain range. In the ammonia electrooxidation reaction process, the catalyst prepared at -0.05 V (vs. SCE) had not only better persistence and stability, but also the lowest catalyst load and overpotential. Because of the different potential between electrochemical electrolysis of ammonia and water, it is possible to supply hydrogen for the fuel cell via ammonia electrolyzing. When at low current density(<10 mA/cm²), fuel cells could provide energy to ammonia electrolysis cell while still having more than 40% additional power for other usages.