Efficient Electrocatalytic Nitrogen Reduction to Ammonia on Ultrafine Sn Nanoparticles
Zhihui Xue, Changning Sun, Ming Zhao, Yuhuan Cui, Yanbin Qu, Haibin Ma, Zhili Wang, Qing Jiang
Abstract
Electrocatalytic nitrogen reduction reaction (NRR) at ambient conditions is a promising route for ammonia (NH3) synthesis but still suffers from low activity and selectivity. Here, ultrafine Sn nanoparticles (NPs) grown on carbon blacks (SnSC/C) have been synthesized through a wet-chemical method using sodium citrate dehydrate as a stabilizing agent. Benefiting from the small sizes of Sn NPs, the SnSC/C catalyst exhibits excellent electrocatalytic performance for NRR with a high Faradaic efficiency of 22.76% and an NH3 yield rate of 17.28 μg h–1 mg–1 in the 0.1 M Na2SO4 electrolyte, outperforming many reported electrocatalysts for NRR under similar conditions. Density functional theory calculation results reveal that the potential-determining step on Sn NPs is the generation of NHNH* through simultaneous hydrogenation of N2* by a H* and a H+/e– pair via Langmuir–Hinshelwood plus Eley–Rideal mechanisms.