High temperature induced S vacancies in natural molybdenite for robust electrocatalytic nitrogen reduction

Abstract

Defect engineering is an important strategy to regulate electronic structure of electrocatalysts for electrochemical N2 fixation, aiming at improving the electron state density and enhancing the adsorption and activation of inert N2. In this paper, a high-temperature strategy to anneal the natural molybdenite under Ar atmosphere was developed, and the as-obtained molybdenite with S vacancies boosted a high activity for N2 reduction reaction. In 0.1 M HCl, the catalyst annealed at 800 °C exhibits a high Faradic efficiency of 17.9% and a NH3 yield of 23.38 μg h−1 mg-1cat. at −0.35 V versus reversible hydrogen electrode, two times higher than that of the pristine molybdenite. The facile one-step annealing method introduces the defects (e.g., S vacancies) in the surface of the natural molybdenite particles to prepare catalysts for generating ammonia by reducing nitrogen at room temperature under ordinary pressure, promoting the development of low-carbon economic prospect.