Enabling Electrocatalytic N2 Reduction to NH3 by Y2O3 Nanosheet under Ambient Conditions

NH3 synthesis consumes 1% of the world’s energy, making it a substantial contribution to greenhouse gas emissions. Electrochemical artificial N2 fixation provides a green and sustainable route over the traditional Haber–Bosch process to enable sustainable NH3 synthesis at ambient conditions while requiring catalysts for the N2 reduction reaction (NRR). Here, we first demonstrate that the Y2O3 nanosheet serves as a high-efficiency nonprecious metal NRR catalyst. When tested at neutral pH, such Y2O3 nanosheet attains a large NH3 yield of 1.06 × 10–10 mol s–1 cm–2 and a high Faradaic efficiency of 2.53% at −0.9 V vs reversible hydrogen electrode with excellent stability and durability. Density functional theory calculations reveal that addition of the first H atom is the potential crucial step, the following hydrogenation steps are feasible, and it is easy to release NH3 molecules.