Synergy of oxygen vacancies and Bi nanoparticles on BiOBr nanosheets for enhanced photocatalytic H2O2 production

Abstract

The surface properties of a photocatalyst play a pivotal role in maximizing the H₂O₂ generation efficiency of the photocatalyst system, especially in spurring the surface catalytic reactions and inhibiting the decomposition of H₂O₂. Herein, a series of Bi/BiOBr-X (X = 1, 2, and 3) photocatalysts co-modified with metal Bi and oxygen vacancies were obtained by a one-step solvothermal method using mannitol as a solvent and a reducing agent. Both Bi modification and the introduction of OVs have important influence on extending the light absorption range, enhancing charge carrier separation and suppressing the recombination of charge carriers as confirmed by UV-vis DRS, EIS, and PL characterization. Besides, the introduction of OVs can lead to an upward shift of CB minimum, which results in a stronger reduction ability of the photogenerated electrons, facilitating the reaction of the photogenerated electrons with molecular oxygen to produce superoxide ions. Meanwhile, the deposition of Bi nanoparticles on the surface of BiOBr nanosheets can significantly inhibit the decomposition of H₂O₂. Benefiting from the synergetic effect of Bi modification and the introduction of OVs, the as-prepared photocatalysts showed enhanced H₂O₂ production activity as high as 100.9 mM h⁻¹ g⁻¹. The present work not only marks a significant advancement in photocatalytic H₂O₂ production technology, but also provides a feasible idea and strategy for photocatalytic production of clean and renewable energy.