Multi-synergy enabling Ni-doped MoS2@N-doped carbon composite as versatile catalysts toward hydrogen production and photovoltaics

Abstract

Construction of efficient non-precious catalyst with desired chemical composition and well-defined nanostructure is of great essential to enhance the kinetics of hydrogen evolution reaction (HER) and triiodide (I₃⁻) reduction reaction (IRR), which is conducive to promote the development of green hydrogen production and obtain impressive photovoltaic performance of dye-sensitized solar cells (DSSCs). Herein, ZIF-8 derived N-doped carbon (NC) wrapped with two-dimensional Ni-doped MoS₂ nanosheets (Ni–MoS₂@NC) are elaborately designed. The catalytic activity of Ni–MoS₂@NC for HER and IRR are significantly improved by modifying electronic structure through heteroatom doping. The optimized Ni–MoS₂@NC has lower overpotential of 122 mV at 10 mA cm⁻² in comparison with counterpart. Meanwhile, the power conversion efficiency (PCE) of DSSCs based on Ni–MoS₂@NC CE catalyst is comparable to that of Pt. Density functional theory (DFT) calculation is used to unveil the mechanism of Ni–MoS₂@NC for alkaline HER and IRR, namely, the multi-synergy of various sites endows Ni–MoS₂@NC with appropriate Gibbs free energy for H∗ adsorption and water dissociation energy, while the top and interfacial S sites of Ni–MoS₂@NC are responsible for the adsorption and activation of I₃⁻. Our work provides a feasible route to design efficient catalysts in the field of energy conversion and understand mechanism.