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

Fe doped InVO4 nanosheets with abundant oxygen vacancies for selective electroreduction of N2 to NH3. [Display omitted] •Fe-InVO4 nanosheets with oxygen vacancies are synthesized by metal doping.•The structure can adsorb and activate N2, and inhibit the competition of HER.•Fe-InVO4 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 InVO4 nanosheets to generate abundant oxygen vacancies, which significantly boost the electrochemical N2 reduction performance with high selectivity. Benefiting from the optimal Fe content, the catalyst achieves a high NH3 yield of 17.23 μgh-1mg-1cat. 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 N2 is preferentially adsorbed on Fe sites doped in InVO4 (110) surface and reduced to ammonia via the distal pathway. The oxygen vacancies generated by the introduction of Fe synergistically activate N2.