Fe doped InVO4 nanosheets with rich surface oxygen vacancies for enhanced electrochemical nitrogen fixation

Abstract

Fe doped InVO 4 nanosheets with abundant oxygen vacancies for selective electroreduction of N 2 to NH 3. • Fe-InVO 4 nanosheets with oxygen vacancies are synthesized by metal doping. • The structure can adsorb and activate N 2 , and inhibit the competition of HER. • Fe-InVO 4 nanosheets exhibit a remarkable catalytic activity for NRR. • The distal pathway is proposed as catalytic mechanism of NRR by DFT calculations. Electrocatalytic nitrogen fixation shows a promising possibility for converting nitrogen to ammonia. We demonstrate Fe as an effective dopant for modulating the electronic structure of InVO 4 nanosheets to generate abundant oxygen vacancies, which significantly boost the electrochemical N 2 reduction performance with high selectivity. Benefiting from the optimal Fe content, the catalyst achieves a high NH 3 yield of 17.23 μgh -1 mg -1 cat. with a Faradaic efficiency up to 14.27% at −0.4 V versus reversible hydrogen electrode in 0.1 M HCl with electrochemical and structural stability. The catalytic mechanism is explored by theorical calculations. Density functional theory (DFT) calculations elucidate that N 2 is preferentially adsorbed on Fe sites doped in InVO 4 (1 1 0) surface and reduced to ammonia via the distal pathway. The oxygen vacancies generated by the introduction of Fe synergistically activate N 2 .