TiO<sub>2</sub> Anchored Cu Single Atoms Catalysts Boost Nitrite Electroreduction to Ammonia for Water Remediation
Mingming Sun, Wenrui Wan, Xiaoli Zhao, Chunfeng Shao, Ning Liu, Maohong Fan, Jianji Wang
Abstract
Abstract The electrochemical conversion of harmful pollutant nitrite (NO 2 − ) in wastewater to NH 3 is an effective strategy for water remediation and production of value‐added chemicals. However, achieving high NH 3 yield and selectivity is challenging due to the low catalyst activity and competitive H 2 and N 2 H 4 byproducts. Herein, for the first time, Cu single‐atom electrocatalysts on TiO 2 (Cu 1 /TiO 2 ) are designed for nitrite reduction to NH 3 in a neutral aqueous electrolyte. The optimal Cu 1 /TiO 2 exhibits an exceptional NH 3 production rate of 21.2 mg h −1 mg cat −1 and a high NH 3 Faradaic efficiency of 96.0% at −1.0 V (vs RHE), representing one of the best electrocatalytic performance ever achieved. Impressively, the NO 2 − (0.1 mol L −1 ) can be completely conversed in 8 h electrolysis. The experimental studies and theoretical calculations uncover that the single atoms Cu narrows the bandgap of TiO 2 and improves the electron transfer in Cu 1 /TiO 2 , and the single‐atom Cu and TiO 2 synergistically activate NO 2 − , stabilize the *NO intermediate, and reduce the energy barrier of the rate‐determining step (*NH 3 →NH 3 ), thus resulting in remarkable electrocatalytic activity and selectivity for the reduction of nitrite to NH 3 . This study provides a new strategy for simultaneous NH 3 production and water remediation at ambient conditions by using single‐atom catalysis.