Highly Efficient and Robust Nickel Phosphides as Bifunctional Electrocatalysts for Overall Water-Splitting

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• 作者：Jiayuan Li ; Jing Li ; Xuemei Zhou ; Zhaoming Xia ; Wei Gao ; Yuanyuan Ma ; Yongquan Qu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：May 4, 2016
• 年：2016
• 卷：8
• 期：17
• 页码：10826-10834
• 全文大小：607K
• 年卷期：0
• ISSN：1944-8252

文摘

To search for the efficient non-noble metal based and/or earth-abundant electrocatalysts for overall water-splitting is critical to promote the clean-energy technologies for hydrogen economy. Herein, we report nickel phosphide (Ni_xP_y) catalysts with the controllable phases as the efficient bifunctional catalysts for water electrolysis. The phases of Ni_xP_y were determined by the temperatures of the solid-phase reaction between the ultrathin Ni(OH)₂ plates and NaH₂PO₂·H₂O. The Ni_xP_y with the richest Ni₅P₄ phase synthesized at 325 °C (Ni_xP_y-325) delivered efficient and robust catalytic performance for hydrogen evolution reaction (HER) in the electrolytes with a wide pH range. The Ni_xP_y-325 catalysts also exhibited a remarkable performance for oxygen evolution reaction (OER) in a strong alkaline electrolyte (1.0 M KOH) due to the formation of surface NiOOH species. Furthermore, the bifunctional Ni_xP_y-325 catalysts enabled a highly performed overall water-splitting with ∼100% Faradaic efficiency in 1.0 M KOH electrolyte, in which a low applied external potential of 1.57 V led to a stabilized catalytic current density of 10 mA/cm² over 60 h.