N, P co-doping triggered phase transition of MoS2 with enlarged interlayer spacing for efficient hydrogen evolution

Abstract

Molybdenum disulfide (MoS₂)-based transition-metal chalcogenides are considered to be cost-efficient, environmentally-friendly, and stable materials in the application of electrocatalytic hydrogen production. However, the low density and poor reactivity of active sites within the basal plane of MoS₂ hinder hydrogen evolution reaction (HER). Herein, we reported that N, P co-doped in the basal plane of MoS₂ (N, P-MoS₂) can convert the parts of 2H MoS₂ to 1T MoS₂ and enlarge interlayer spacing for an efficient HER. Subsequently, electrochemical tests revealed that N, P-MoS₂ showed an overpotential of 179 mV at 10 mA cm⁻², a corresponding Tafel slope of 143 mV dec⁻¹, and remarkable long-term stability over 20 h. In addition, we combined these findings with theoretical results from density functional theory (DFT) simulations. The results confirmed that the synergistic effect of N and P activated the HER catalytic activity at the edge of N-MoS₂. In short, the synergy improved the conductivity of N-MoS₂ and promoted the rapid transfer of charge to achieve high-performance HER activity. The work provides new insight into the synergistic effect of N and P co-doped in the basal plane of MoS₂, as well as a new pathway for the rational design of efficient HER electrocatalysts.