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Nickel phosphide (Ni2P) has been widely explored toward hydrogen evolution reaction (HER) for desirable durability and high performance. Tuning the electronic structures and morphologies of Ni2P plays a pivotal role in the improvement of HER performance. In this work, three Ni2P catalysts were fabricated by different strategies and their HER properties were compared. It was found that the bicontinuous porous structured Ni2P on Ni foam (Ni2P /NF−EHP) prepared using coupled electroless nickel‐phosphorus (Ni−P) plating, hydrothermal synthesis and low temperature phosphorization techniques, exhibits the best catalytic activity and a wide pH adaptability. The overpotential at 10 mA cm−2 and Tafel slope are 78 mV and 33 mV dec−1 in 0.5 M H2SO4, those in 1 M PBS are 125 mV and 93 mV dec−1, and 101 mV and 76 mV dec−1 in 1 M KOH. Additionally, the Ni2P/NF−EHP‐catalyzed HER process is also applicable for nitrate reduction with a remarkable removal efficiency of 92.6 %. This catalyst also exhibits a desirable durability both in HER and nitrate reduction. This work offers an efficient strategy to exploit compatible pH‐universal HER catalysts, explores the engineering application of HER process in nitrate reduction. [ABSTRACT FROM AUTHOR]

Developing robust and low-cost hydrogen evolution reaction (HER) catalysts in alkaline media still faces enormous challenges. Herein, a novel 3D self-supporting nickel phosphorus/nickel phosphide/carbon cloth (Ni–P/Ni2P/CC) composite was fabricated by using combined processes of nickel phosphorus electrodeposition, hydrothermal synthesis and low temperature phosphorization techniques, for the loading of Ni–P nanoparticles and Ni2P nanosheets onto the surface of CC. The characteristics of the fabricated Ni–P/Ni2P/CC composite in terms of crystallinity, surface morphology and chemical components were analyzed, and the HER properties in alkaline solution were evaluated. The synthesized Ni–P/Ni2P/CC composite exhibits preeminent HER activity; among the three composites, the Ni–P/Ni2P/CC-2 sample displays the highest catalytic activity with a low overpotential of 95 mV to afford a current density of 10 mA cm−2. Moreover, this composite exhibits outstanding electrochemical stability (without apparent loss in HER activity after 2000 cyclic voltammetry cycles). For this self-supporting Ni–P/Ni2P/CC composite, the deposited Ni–P nanoparticles fill the sites not occupied by Ni2P nanosheets on the surface of CC, and thus the effect of the synergy between Ni–P and Ni2P on the enhancement in HER performance is verified. The fabricated Ni–P/Ni2P/CC composite deserves to be considered as an appealing candidate for HER application in alkaline solution. [ABSTRACT FROM AUTHOR]