“…Transition metal phosphides (TMPs) have received tremendous attention due to the Pt-like electronic structure and low price. − However, the inherent nature of low electrical conductivity and aggregated active sites and then high voltages are required to drive the electrocatalytic water-splitting. , To enhance the electrocatalytic activity of TMPs, porous structure designing, defect and heteroatom doping engineering are considered as effective strategies. − The porous structure can increase the specific surface area of the catalyst, improve the mass/electron transport efficiency, and then increase the catalytic activity. , Therefore, fabricating TMPs with porous structures is an effective approach to enhance the electrocatalytic performance. Moreover, N-doping is also a promising approach to improve the water splitting ability. , For HER, pyrrolic N can adjust the electronic structure of metal sites and promote the adsorption of H*. , Pyridinic N can prevent the adsorption of OH* to release the active sites .…”