Highly efficient and stable electrocatalysts toward hydrogen evolution reaction (HER) under large current density are essential for alkaline water splitting. Herein, an active and durable CoMoO4-based HER electrocatalyst is developed, with a coupling of surface phosphorization and polypyrrole (PPy) modification to accelerate water dissociation and prevent alkaline corrosion during HER process, ensuring great catalyst stability. The prepared PPy-CoMoO4/P@NF catalyst achieves perfect HER activity with only 242.1 mV overpotential at the industrial current density of 1000 mA·cm−2 in 1.0 M KOH as well as a low Tafel slope of 39.0 mV dec−1. Moreover, PPy modification greatly inhibits the alkaline corrosion and the catalyst exhibits stable operation for 100 h at 1000 mA·cm−2 with a conservation rate of 98.5 %. Electrochemical tests and theoretical calculations reveal that the multiple interfaces formed by CoMoO4/CoP/PPy significantly reduce the energy barrier of hydrolysis and improve the interfacial adsorption of Hads. Meanwhile, the surface phosphating changes the Gibbs free energy of rate-determining step (RDS) from −0.54 to −0.29 eV, optimizing the energy barriers for hydrogen adsorption-desorption. Remarkably, an electrolyzer with PPy-CoMoO4/P @NF as cathode catalyst only needs a cell voltage of 1.92 V at 1000 mA cm−2 for overall water splitting. This study provides an effective way to develop highly efficient and stable HER catalysts toward industrial water splitting.

中文翻译：

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CoMoO4 表面磷化耦合聚吡咯改性可实现高效析氢


大电流密度下高效、稳定的析氢反应（HER）电催化剂对于碱性水分解至关重要。本文开发了一种活性耐用的 CoMoO4 基 HER 电催化剂，通过表面磷化和聚吡咯（PPy）改性相结合，加速水解离并防止 HER 过程中的碱腐蚀，确保催化剂的良好稳定性。所制备的PPy-CoMoO4/P@NF催化剂在1.0 M KOH中1000 mA·cm−2的工业电流密度下实现了完美的HER活性，过电势仅为242.1 mV，并且塔菲尔斜率低至39.0 mV dec−1。此外，PPy改性极大地抑制了碱腐蚀，催化剂在1000 mA·cm−2下稳定运行100 h，保存率为98.5 %。电化学测试和理论计算表明，CoMoO4/CoP/PPy形成的多重界面显着降低了水解的能垒，提高了Hads的界面吸附。同时，表面磷化将决速步骤吉布斯自由能（RDS）从-0.54 eV更改为-0.29 eV，优化了氢吸附-解吸的能垒。值得注意的是，以 PPy-CoMoO4/P @NF 作为阴极催化剂的电解槽在 1000 mA cm−2 下仅需要 1.92 V 的电池电压即可实现整体水分解。这项研究为开发用于工业水分解的高效且稳定的HER催化剂提供了有效的方法。