S-Doped Sb₂O₃ Nanorods for Electrocatalytic Nitrogen Reduction

Abstract

Sulfur-doped Sb2O3 nanorods (X-Sb2O3) have been synthesized via a self-assembly process with subsequent calcination, using bulk Sb as the precursor and H2SO4 as the sulfur source. The obtained X-doped Sb2O3 nanorods were confirmed as efficient and stable catalysts for electrochemical nitrogen reduction, which exhibited a superior ammonia yield of 6.88 μg h–1 cm–2 with a Faradaic efficiency of 32.5% at −0.18 V versus RHE. Moreover, the doping amount of sulfur in X-Sb2O3 could be controlled by the calcination temperatures in a muffle furnace. Density functional theory calculations revealed that N2 was readily adsorbed on the O atom of the 300-Sb2O3 surface, and the subsequent reduction reactions further occurred on the O active site by the distal mechanism. Meanwhile, the superior electrocatalyst performance of 300-Sb2O3 was attributed to sulfur doping, which effectively tuned the electronic structures of Sb2O3 to promote the adsorption and activation ability of N2. This work provides an easy and efficient way to dope non-metals in Sb2O3 for excellent electrocatalytic performance.