Transition metal doping BiOBr nanosheets with oxygen vacancy and exposed {102} facets for visible light nitrogen fixation

Abstract

Artificial photocatalytic N2 reduction to NH3 under ambient conditions represents a promising alternative way for the industrial N2 fixation by Haber − Bosch process. This work reports the simultaneous engineering of BiOBr nanosheets with exposed {102} facets by means of transition metal (Fe, Mo, Ni) doping and oxygen vacancies (OVs) that aid to expose internal metal dopants toward efficient visible light N2 fixation. The synergy of transition metal doping and OVs results in the modulated band structures, improved charge carrier separation as well as electron transfer to N2, thereby leading to enhanced N2 adsorption and activation ability over modified BiOBr nanosheets. In particular, the Fe-doped BiOBr with OVs possesses the optimal photocatalytic activity of NH3 yield of 46.1 μmol g–1 h–1 without any sacrificial agent, which is 6-fold that of pristine BiOBr. The findings will shed new light on rational engineering of adsorption, activation sites and charge carrier separation for designing efficient N2 fixation photocatalysts.