Selective Ammonia Synthesis via Electrocatalytic Nitrate Reduction Reaction on Molybdenum Selenide with Selenium Vacancy

Electrochemical reduction of nitrate ions to ammonia, the nitrate reduction reaction (NO3RR), offers an attractive path for the valorization of pollutants to valuable chemicals without the accompanying high carbon footprint of the century-old Haber-Bosch process. An electrocatalyst with enhanced activity, higher selectivity, and good durability is a primary requirement. We report herein density functional theory plane wave calculations predicting Se vacancies in molybdenum diselenide as catalytic active sites for efficient NO3RR. As a proof-of-concept, we also report the formation and characterization of Se vacancy-rich exfoliated molybdenum diselenide (ex-MoSe2) by a chemical exfoliation method. ex-MoSe2, coated on a glassy carbon electrode, reveals promising NO3RR activity with a Faradaic efficiency of 93.6% and a yield rate of 4.9 mmol gcat–1 h–1 for ammonia production. The exfoliation and vacancy engineering strategies described herein can serve as an inspiration for the development of improved electrode materials engineering for electrocatalytic applications.