Industrial & Engineering Chemistry Research, Vol.57, No.49, 16622-16627, 2018
Enabling Electrocatalytic N-2 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 N-2 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 N-2 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 x 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.