Core@shell structured Au@SnO2 nanoparticles with improved N2 adsorption/activation and electrical conductivity for efficient N2 fixation

The design of electrocatalysts with enhanced adsorption and activation of nitrogen (N-2) is critical for boosting the electrochemical N-2 reduction (ENR). Herein, we developed an efficient strategy to facilitate N-2 adsorption and activation for N-2 electroreduction into ammonia (NH3) by vacancy engineering of core@shell structured Au@SnO2 nanoparticles (NPs). We found that the ultrathin amorphous SnO2 shell with enriched oxygen vacancies was conducive to adsorb N-2 as well as promoted the N-2 activation, meanwhile the metallic Au core ensured the good electrical conductivity for accelerating electrons transport during the electrochemical N-2 reduction reaction, synergistically boosting the N-2 electroreduction catalysis. As confirmed by the N-15-labeling and controlled experiments, the core@shell Au@amorphous SnO2 NPs with abundant oxygen vacancies show the best performance for N-2 electroreduction with the NH3 yield rate of 21.9 mu g h(-1) mg(cat)(1), and faradaic efficiency of 15.2% at -0.2 V-RHE, which surpass the Au@crystalline SnO2 NPs, individual Au NPs and all reported Au-based catalysts for ENR. (C) 2019 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.