A\nUniversal Strategy for Carbon-Supported Transition Metal Phosphides\nas High-Performance Bifunctional Electrocatalysts towards Efficient\nOverall Water Splitting

Exploring\ncost-effective and general approaches for highly active and stable\nbifunctional transition metal phosphide (TMP) electrocatalysts towards\noverall water splitting is greatly desirable and challenging. Herein,\na general strategy combining sol–gel and a carbonization-assisted\nroute was proposed to facilely fabricate a series of TMP nanoparticles,\nincluding CoP, MoP, FeP, Cu2P, Ni2P, PtP2, FeNiP, CoNiP, and FeCoNiP, coupled in an amorphous carbon\nmatrix with one-step carbon composite formation. The resultant NiFeP@C\nexhibits excellent activities as a bifunctional electrocatalyst toward\noxygen evolution reaction (OER) and hydrogen evolution reaction (HER)\nwith low overpotentials of 260 and 160 mV, respectively, at 10 mA/cm2 in 1 M KOH solution. With the NiFeP@C electrocatalyst as\nboth electrode materials, an integrated electrolyzer can deliver 47.0\nmA/cm2 of current density at 1.60 V, better than the assembled\nPt/C20∥IrO2 counterpart. The encapsulation of NiFeP\nnanoparticles in the carbon matrix effectively prevents their corrosion\nand leads to almost unfading catalytic activities for more than 20\nh for either the HER, OER, or overall water splitting, outperforming\nrecently reported bifunctional electrocatalysts. The coexistence of\nNi, Fe, P, and C would have synergetic effects to accelerate charge\ntransfer and promote electrocatalytic activity. This universal strategy\nfor TMP-based composites opens up a new avenue to explore TMPs as\nmultifunctional materials for various applications.