Atomically dispersed Ni on Mo2C embedded in N, P co-doped carbon derived from polyoxometalate supramolecule for high-efficiency hydrogen evolution electrocatalysis

Herein, a novel supramolecular-confinement pyrolysis strategy was proposed to construct ultrafine Ni-Mo2C nanoparticles uniformly distributed on N,P co-doped carbon (NPC) by using polyoxometalate supramolecular aggregate as precursor. Ni-Mo2C/NPC exhibits remarkable electrocatalytic activity for hydrogen evolution reaction (HER) in both acidic and alkaline conditions, as well as superior long-term durability. Combining EXAFS with DFT calculations, we demonstrate that Ni species were atomically dispersed and anchored by Mo2C lattice and P atoms from NPC, thus defining Mo(C)–Ni–P active sites, which enhance the intrinsic catalytic activity of Mo2C by atomic-scale Ni doping and Ni–P catalyst-substrate chemical coupling. The Mo(C)–Ni–P sites have optimal hydrogen adsorption free energies and can precisely regulate and activate the neighboring C, leading to excellent HER performance. This work developed a “bottom-up” polyoxometalate-based supramolecular approach for in-situ assembly of high-active HER catalytic sites, which will provide opportunities to design and fabricate low-cost and efficient atomic-scale catalysts for clean energy conversion.