Iron-Doped MoO<sub>3</sub> Nanosheets for Boosting Nitrogen Fixation to Ammonia at Ambient Conditions
Haohong Xian, Haoran Guo, Jiaojiao Xia, Qiru Chen, Yonglan Luo, Rui Song, Tingshuai Li, Enrico Traversa
Abstract
Nitrogen can be electrochemically reduced to produce ammonia, which supplies an energy-saving and environmental-benign route at room temperature, but high-efficiency catalysts are sought to reduce the reaction barrier. Here, iron-doped α-MoO3 nanosheets are thus designed and proposed as potential catalysts for fixing N2 to NH3. The α-MoO3 band structure is intentionally modulated by the iron doping, which narrows the band gap of α-MoO3 and turns the semiconductor into a metal-like catalyst. Oxygen vacancies, generated by substituting Mo6+ for Fe3+ anions, are beneficial for nitrogen adsorption at the active sites. In 0.1 M Na2SO4, the Fe-doped MoO3 catalyst reached a high faradaic efficiency of 13.3% and an excellent NH3 yield rate of 28.52 μg h–1 mgcat–1 at −0.7 V versus reversible hydrogen electrode, superior to most of the other metal-based catalysts. Theoretical calculations confirmed that the N2 reduction reaction at the Fe–MoO3 surface followed the distal reaction path.