Realizing High Water Splitting Activity on Co3O4 Nanowire Arrays under Neutral Environment

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• 作者：Jingfu He ; Yanhua Peng ; Zhihu Sun ; Weiren Cheng ; Qinghua Liu ; Yajuan Feng ; Yong Jiang ; Fengchun Hu ; Zhiyun Pan ; Qing Bian ; Shiqiang Wei
• 关键词：Cobaltosic oxide ; Water oxidation catalyst ; neutral electrolyte ; Mass transfer ; Buffering agents
• 刊名：Electrochimica Acta
• 出版年：10 February, 2014
• 年：2014
• 卷：119
• 期：Complete
• 页码：64-71
• 全文大小：1430 K

文摘

Enhancing catalytic water-splitting activity under mild environments is significant to solve the long-standing cost, safety and stability issues in photoelectrochemical cells. Here, we demonstrate the crucial role of improving surface H transfer in achieving efficient water-splitting catalytic activity of Co₃O₄ nanowire arrays in near-neutral pH working electrolytes. Under weak OH circumstances, the impedance of mass transfer quickly multiplies and the catalytic current declines to a current plateau in the region of 1.7-2.1 V vs. RHE, due to the surface H concentration approaching a threshold value in the range of 10^鈭?-10^鈭? M. The proper choice of buffering agents to facilitate the mass transfer, with 0.1 M KPi as a prototype, would decrease the overpotential by 500 mV for neutral electrolyte and favors to achieve a catalytic current comparable to that under strong alkali environments (pH > 13). These results also provide a solid guideline for extending the electrocatalytic utility of other transition metal catalysts to near-neutral pH environments.