Improving electrochemical nitrate reduction activity of layered perovskite oxide La2CuO4 via B-site doping

Electrochemical reduction of nitrate into ammonia (NO3-RR) has attracted great attentions because of the potential application for environmental remediation and energy storage. Despite many pioneering works on electrocatalysts development, the correlation between material properties and NO3-RR activity is still not fully understood. Herein, taking layered Ruddlesden-Popper type oxide La2CuO4 as a model system, we demonstrate B-site cation doping as an effective approach for modulating NO3-RR activities. While Co dopant at Cu site strongly enhanced the NO3-RR activity and NH3 selectivity, Zn and Ni dopants lead to slightly enhanced and suppressed NO3-RR performance, respectively. The distinct reaction kinetics of NO3-RR on La2Cu0.8M0.2O4 with different dopants are further revealed by in-situ Fourier transform infrared spectroscopy measurement. Synchrotron-based X-ray absorption spectroscopy showed that B-site doping can effectively regulate metal-oxygen hybridization, leading to strongly tuned surface adsorption characteristics and NO3-RR activity. The results of this work can guide the design of highly active (electro)catalysts for environmental and energy devices.