WO₃ nanosheets rich in oxygen vacancies for enhanced electrocatalytic N₂ reduction to NH₃

The Haber–Bosch process for industrial-scale NH₃ production suffers from harsh conditions and serious CO₂ release. Electrochemical N₂ reduction is an alternative approach to synthesize NH₃ under ambient conditions, but it requires highly-efficient electrocatalysts for the N₂ reduction reaction (NRR). In this Communication, we demonstrate that WO₃ nanosheets rich in oxygen vacancies (R-WO₃ NSs) exhibit greatly enhanced NRR performances. In 0.1 M HCl, such R-WO₃ NSs achieve a large NH₃ yield of 17.28 μg h⁻¹ mg_cat.⁻¹ and a high faradaic efficiency of 7.0% at −0.3 V vs. a reversible hydrogen electrode, much superior to the WO₃ nanosheets deficient in oxygen vacancies (6.47 μg h⁻¹ mg_cat.⁻¹ and 1.02%). Remarkably, R-WO₃ NSs also show high electrochemical stability.