Crystalline CoP@ Amorphous WP<sub>2</sub> Coaxial Nanowire Arrays as Bifunctional Electrocatalyst for Water Splitting
Xinyue Wei, Linyin Huang, Yuan Yu, Dongfeng Sun, Yanning Qu, Xiaoya Yuan, Jianlong Wen, Qingmei Su, Fangyou Meng, Gaohui Du, Bingshe Xu, Kai Wang
Abstract
Abstract The crystalline CoP@ amorphous WP 2 core–shell nanowire arrays are oriented grown on the Ni foam (CoP@WP 2 /NF). The amorphous WP 2 shell provides more active sites, and the interface charge coupling accelerates the kinetic of the catalytic reaction, making the CoP@WP 2 /NF catalysts excellent activity. In acidic, only 13 and 97 mV overpotentials are needed to reach 10 mA cm −2 and 100 mA cm −2 , respectively, which are the lowest overpotentials among all reported Transition metal phosphide (TMP) catalysts, of course, much lower than that of the Pt/C catalyst (31 mV at 10 mA cm −2 , 120 mV at 100 mA cm −2 ). In alkaline, the Hydrogen evolution reaction (HER) overpotentials at 10 mA cm −2 and 100 mA cm −2 are 68 and 136 mV, respectively, which are also lower than that of most reported TMPs catalysts. The CoP@WP 2 /NF catalysts also show excellent Oxygen evolution reaction (OER) performance in alkaline, and its OER overpotential at 10 mA cm −2 is only 254 mV. The voltage of the CoP@WP 2 /NF‐2h‖CoP@WP 2 /NF‐2 h cell is only 1.37 V at 10 mA cm −2 , which is even lower than that of Pt/C‖Ru 2 O cell (1.52 V). Specially, when the current density is greater than 150 mA cm −2 , the energy consumption advantage of the CoP@WP 2 /NF‐2 h‖CoP@WP 2 /NF‐2 h cell is more obvious.