High-performance nitrogen photofixation by Bi2Sn2O7 nanoparticles enriched with oxygen vacancies

Development of effective technologies for artificial nitrogen fixation under mild conditions is of fundamental and technological significance, as the traditional production of NH3 by the Haber-Bosch process entails a high energy consumption and carbon emission. In this study, Bi2Sn2O7 ultrasmall nanoparticles of the pyrochlore phase are synthesized hydrothermally, and the photocatalytic activity towards nitrogen fixation is found to be modulated by the addition of sodium oleate. Among the series, the optimal sample displays a photocatalytic performance with an NH3 production rate of 231 μmol g−1 h−1, due to the formation of a high specific surface area, a large number of active sites for N2 adsorption, and extensive lattice oxygen vacancies. In conjunction with results from first principles calculations, the Bi species around the O2-site oxygen vacancies are found to play a key role in the adsorption and activation of N2. Results from this study highlight the significant potential of Bi2Sn2O7 nanostructures as high-performance catalysts for solar ammonia synthesis. Data will be made available upon request from the authors.