Superhydrophilic Al-Doped NiP₂ Nanosheets as Efficient Electrocatalysts for Hydrogen Evolution Reaction

The surface wettability of an electrocatalyst plays an important role in electrocatalysis of the hydrogen evolution reaction from water splitting. Herein, Al-doped NiP₂ nanosheets are synthesized on carbon fiber paper (Al–NiP₂ NSs/CFP) with a superhydrophilic and aerophobic surface as a hydrogen evolution reaction electrode. The Al–NiP₂ NSs/CFP electrode exhibits superior hydrogen evolution activity with a low overpotential of 58 mV to achieve 10 mA cm⁻² in 0.5 m H₂SO₄. In particular, it even exhibits better electrochemical performance than commercial Pt/C electrodes at high current densities. Theoretical calculations indicate that Al dopants can alter the electronic structures and optimize the hydrogen adsorption free energy of NiP₂. The superhydrophilic and aerophobic surface favors the H₂ bubbles release from the electrocatalyst surface and promotes the hydrogen evolution reaction (HER) performance at high current densities. Potential ways to fabricate efficient non-noble metal electrocatalyts for large-scale industrial hydrogen production applications are provided through electronic structure engineering and surface constructing.