Revealing the In Situ Evolution of Tetrahedral NiMoO₄ Micropillar Array for Energy‐Efficient Alkaline Hydrogen Production Assisted by Urea Electrolysis

Abstract

The great promise of the combination of urea oxidation reaction (UOR) with hydrogen evolution reaction (HER) to simultaneously achieve wastewater treatment and hydrogen production calls for the rational design of high‐performance electrocatalysts. Herein, the reconstruction with the formation of Ni 2 P and Mo 2 O 7 2− on the surface can largely enhance the alkaline HER activity of P‐NiMoO 4 by on‐site electrochemical activation strategy. Systematic experimental results indicate that the reconstruction process enables the exposure of additional Ni sites and the adjustment of hydrogen adsorption to facilitate HER kinetics. Ultimately, a highly efficient alkaline HER electrode with low overpotential of −48.9 mV for 10 mA cm −2 is achieved. More importantly, a UOR electrolyzer assembled with A‐P‐NiMoO 4 as the cathode and P‐NiMoO 4 as the anode exhibits impressive performance with a small cell voltage of 1.363 V for 10 mA cm −2 . The application of the fabricated electrodes in a practical cell driven by a commercial dry battery (1.5 V) demonstrates efficient and stable hydrogen production, making the developed strategy promising for the rational design of highly active electrocatalysts for green hydrogen production.