Hexamethylenetetramine induced multidimensional defects in Co₂P nanosheets for efficient alkaline hydrogen evolution

Crystal engineering is an important way to improve the catalytic performance of transition-metal phosphides. In this work, we propose a strategy for constructing multi-dimensional defects induced by hexamethylenetetramine, which effectively introduces grain boundaries, N doping and P vacancies into Co₂P nanosheets, and improves the activity and stability of the catalyst. Due to the synergistic effect of the multi-dimensional defects, the Co₂P nanosheets exhibit excellent HER catalytic performance, especially at a large current density of 100 mA cm^-2 with an overpotential of only 159 mV. Under 1 M KOH electrolyte and current density of 10 mA cm^-2, the long-term test for 36 h shows that the catalyst maintains a very high stability.