The inferior performance of non-precious metals on electrocatalytic hydrogen evolution can be mainly attributed to the inappropriate adsorption strength of intermediates. A core–shell heterostructure of CoP@Ni is developed by hydrothermal reaction, thermal phosphorization and subsequent electrodeposition, with metallic Ni supported by CoP nanowire array. The as-prepared CoP@Ni core–shell heterostructure nanowire array has a superior activity on hydrogen evolution in alkaline electrolyte, with an overpotential of 71 mV to drive 10 mA cm −2 and a Tafel slope of 66 mV dec -1 . The electronic structure of CoP@Ni is tuned for modulating the adsorption strength of intermediates. The theoretical calculations reveal that CoP@Ni has metallic characteristics with a zero-bandgap, which leads to the promoted charge transfer. More importantly, the intrinsic activity of CoP@Ni is greatly increased, with a lower energy barrier in the reaction pathway. This work points out the importance of constructing the heterostructure for improving the intrinsic activity, which can pave the way to the exploration of high-performance and cost-effective electrocatalysts for hydrogen production.
Jie Liu,Yu Chen,Yin Wang,Lu Liu,Qi Chen,Qingqing Shi,Luyi Huang,Xing Chen,Kun Xie
Cobalt phosphide has excellent electrical conductivity, metallic properties, and thermal stability. However, its application is limited due to the few active sites exposed in electrochemical reactions and poor structural stability. Herein, we adopt the strategies of material compounding and structural design to construct CoP@Ni(OH)2 bilayer nanosheets. The bilayer nanosheet structure can provide abundant transport paths for electrons and ions while also exposing more electroactive sites. In addition, the close contact and mutual support of the bilayer nanosheet structure can significantly alleviate material morphological collapse during charging/discharging processes, improving the cycle stability. The advantages of multiple components were combined in CoP@Ni(OH)2 to provide multiple valances for the faradaic redox reactions. The CoP@Ni(OH)2 manifested a specific capacity of 1697.8 C g−1 at 1 A g−1 and maintained a high rate capability of 35.0% even at 20 A g−1. Moreover, the electrode, had great cycling stability, retaining 83.9% of its capacity at 6 A g−1 after 7000 cycles. The asymmetric supercapacitor made of CoP@Ni(OH)2//activated carbon delivered 53.2 W h kg−1 at 800 W kg−1.
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