Cui Xun, Guo Wenlong, Zhou Ming, Yang Yang, Li Yanhong, Xiao Peng, Zhang Yunhuai, Zhang Xiaoxing
College of Chemistry and Chemical Engineering, and ‡College of Physics, Chongqing University , Chongqing 400044, China.
ACS Appl Mater Interfaces. 2015 Jan 14;7(1):493-503. doi: 10.1021/am506554b. Epub 2014 Dec 17.
Ni-based bimetallic alloys have superior physiochemical characteristics compared to monometallic Ni. In this study, a new type of low cost bimetallic NimCon (n + m = 4) electrocatalysts with high active surface were synthesized on Ti substrate through a hydrogen evolution assisted electrodeposition method. The as-prepared NimCon were characterized by XRD, EDS, and SEM. It was revealed that the composition, surface morphology, as well as the crystal phase structure of the bimetallic NimCon electrocatalysts were significantly changed with the increased content of cobalt. Electrochemical measurements showed that the bimetallic NimCon catalysts, compared with the monometallic Ni, have superior catalytic activity and stability toward the methanol electrooxidation reaction. Additionally, Ni2Co2 sample presented the highest oxidation current density and the best durability. The mechanism study based on electrochemical experiments and density functional theory based calculations showed that the doping of Co in NimCon can signally improve the surface coverage of the redox species, weaken the CO adsorption, as well as adjust the CH3OH adsorption. Such understanding is of important directive significance to design efficient nonprecious catalysts.
与单金属镍相比，镍基双金属合金具有优异的物理化学特性。在本研究中，通过析氢辅助电沉积法在钛基底上合成了一种新型的具有高活性表面的低成本双金属NimCon（n + m = 4）电催化剂。采用X射线衍射（XRD）、能谱分析（EDS）和扫描电子显微镜（SEM）对制备的NimCon进行了表征。结果表明，随着钴含量的增加，双金属NimCon电催化剂的组成、表面形貌以及晶相结构均发生了显著变化。电化学测试表明，与单金属镍相比，双金属NimCon催化剂对甲醇电氧化反应具有优异的催化活性和稳定性。此外，Ni2Co2样品表现出最高的氧化电流密度和最佳的耐久性。基于电化学实验和密度泛函理论计算的机理研究表明，在NimCon中掺杂钴可以显著提高氧化还原物种的表面覆盖率，减弱CO吸附，并调节CH3OH吸附。这种认识对设计高效非贵金属催化剂具有重要的指导意义。
