Interfacial electronic engineering of heterostructured Co2P-MoNiP/NF nano-sea-urchin catalysts for efficient and stable hydrogen evolution via water/seawater splitting

Using hydrogen as a fuel is an effective way to combat the energy crisis, at the same time, reduce greenhouse gas emissions. Designing high-performance and low-cost catalysts for the hydrogen evolution reaction (HER) is critical for commercial seawater electrolysis. Here, we designed a heterostructured Co2P-MoNiP/NF nano-sea-urchin catalyst that only showed an overpotential of 46 mV for 10 mA cm−2 to actuate HER in alkaline electrolytes along with superior stability. Theoretical calculations demonstrate that the constructed heterogeneous interfaces effectively promote the redistribution of the charge density and optimize the adsorbed hydrogen intermediates, lowering the hydrogen adsorption free energy barrier and promoting H2 desorption, thus boosting the HER activity. Moreover, the assembled two-electrode electrolyzer only required ultra-low voltages of 1.51 and 1.66 V to deliver current densities of 10 and 100 mA cm−2, respectively. The solar-driven water electrolysis system achieves a high and stable solar-to-hydrogen (STH) conversion efficiency of 19.68 %.