Electron density modulation of MoP by rare earth metal as highly efficient electrocatalysts for pH-universal hydrogen evolution reaction

Abstract

Profiting from Pt-like electronic structure and high electrical conductivity, molybdenum phosphide (MoP) has received widespread attention as a hydrogen evolution reaction (HER) catalyst. Although various effective strategies have been developed to regulate the bare MoP synthesis, the electrocatalytic performance of MoP is still far from satisfactory, especially in pH-universal applications. Recently, doping of heterogeneous elements, particularly for rare earth (RE) metals, has been emerged as an effective method to precisely regulate the local electronic structure of phosphides. Herein, the novel and controllable La/Yb-doped MoP nanoparticles encapsulated in nitrogen-doped carbon matrix (MoP@NC) are synthesized. The as-prepared La/Yb-doped catalysts (RE-MoP@NC (RE = La, Yb)) exhibit fantastic HER electrocatalytic performance for both activity and durability in a wide pH range. Detailed structural characterizations and density functional theory (DFT) calculations validate that the electronic densities around Mo and P atoms are effectively tuned by La/Yb doping atoms, resulting in the optimization in Gibbs free energy of MoP toward the hydrogen adsorption, which can boost its intrinsic HER activity. This research enriches RE-modified catalysts and reveals that the RE metal doping can be extended to other non-noble metal catalysts as a general method.