NaCl-Assisted Ultrasmall Mo2C Nanocrystals Confined in N, S Double-Doped Hierarchical Porous Carbon for Efficient Hydrogen Generation

Abstract

Refining the size of nonprecious metal-based catalysts and restricting them in multiheteroatom-doped hierarchical porous carbon can achieve efficient electrical energy conversion. In this study, ultrasmall Mo2C nanocrystals with an average size of 4.9 nm are fitted to N and S double-doped hierarchical porous carbon (us-Mo2C/N,S-HPC) through a template strategy and used for efficient hydrogen production. First, the metal molybdenum salt is captured and fixed by natural bamboo leaf fibers which are pulverized by a ball mill. Meanwhile, the soluble sodium salt is largely filled in the bamboo leaf tissue. Subsequently, Mo2C nanocrystals formed by high-temperature reduction are uniformly anchored on the bamboo-derived N, S double-doped hierarchical porous carbon. As a result, the prepared us-Mo2C/N,S-HPC requires 150, 197, and 148 mV overpotential to drive a current density of 10 mA cm–1 at pH = 0, 7, and 14, respectively. This improvement is attributed to the synergistic effects of size controllable Mo2C, multidoped heteroatoms, and multiscale assembly structures. Significantly, this study is conducive to the construction of ultrafine nanocrystals and the high-value conversion of waste biomass.