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The study of efficient, robust, and earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) is essential for hydrogen-based energy technologies. Previous works have demonstrated that pyrite-structure materials (e.g., CoS 2, NiSe 2 ) are efficient HER catalysts. Here, we first systematically investigate the nanostructure synthesis of a series of pyrite-phase nickel phosphoselenide materials—NiP 2, Se-doped NiP 2 (NiP 1.93 Se 0.07 ), P-doped NiSe 2 (NiP 0.09 Se 1.91 ), and NiSe 2 —through a facile thermal conversion of Ni(OH) 2 nanoflakes. The similar nanostructures enable a systematic and fair comparison of their structural properties and catalytic activities for HER. We found that NiP 1.93 Se 0.07 shows the best HER performance, followed by NiP 2, NiP 0.09 Se 1.91, and NiSe 2 . Se-doped NiP 2 grown on carbon fiber paper can achieve an electrocatalytic current density of 10 mA cm –2 at an overpotential as low as 84 mV and a small Tafel slope of 41 mV decade –1 . This study not only estabilishes Se-doped NiP 2 as a competitive HER catalyst, but also demonstrates that doping or alloying of developed catalysts (especially doping with anions from another group; e.g., selenium to phosphorus) can improve the HER catalytic activity, which provides a general strategy to improve catalytic efficiencies of existing electrocatalysts for HER.
Zhuo et al. (Wed,) studied this question.