One‐step Mechanical Synthesis of Oxygen‐defect Modified Ultrathin Bi 12 O 17 Br 2 Nanosheets for Boosting Photocatalytic Activity

Oxygen vacancy engineering of novel ultrathin Bi12O17Br2 nanosheets for boosting photocatalytic N2 reduction

The conversion of N₂ to NH₃ is one of the most promising processes in maintaining natural life and chemical production. Photocatalytic nitrogen reduction reaction (NRR) has the advantage of clean and sustainable, which is considered to be an ideal synthesis technology. In this work, we report the successful synthesis of Bi₁₂O₁₇Br₂ ultrathin nanosheets through simple alkali treatment and solvothermal method. The Bi₁₂O₁₇Br₂ ultrathin nanosheets can improve the separation of carriers and the transfer of photogenerated electrons to N₂ molecules, thus improving the photocatalytic efficiency. Of note, the higher Bi/Br atomic ratio in Bi₁₂O₁₇Br₂ is beneficial to broaden the light absorption edge, and the high concentration of O atoms is easy to produce oxygen vacancies on the surface during the synthesis process of Bi₁₂O₁₇Br₂. The abundant oxygen vacancies and high specific surface area enable N₂ molecules and water to have powerful chemical adsorption and activation. In addition, the photocatalytic reduction of N₂ to NH₃ in pure water shows excellent and stable performance, and the average generation rate of NH₃ reaches up to 620.5 μmol·L^-1·h^-1. This study discovers that rich oxygen vacancies and ultrathin morphology may have a significant part in the process of the photocatalytic nitrogen reduction reaction.

Feasible Tuning of Surface OVs on (001) TiO2 for Superior Photocatalytic Nitrogen Fixation Activity

A feasible tuning method for oxygen vacancies was realized by annealing under 3 atm H₂ with (001)-exposed TiO₂ nanosheets. The colored TiO₂ sample exhibits an excellent N₂ photo-fixation rate owing to the abundant oxygen vacancies (OVs) thus demonstrating that annealing with high pressure H₂ is exceedingly efficient for tuning surface OVs.

Reverse construction of dominant/secondary facets in Bi24O31Br10 photocatalysts for boosting electronic transfer

In this paper, it is found that the preferential growth of secondary {117} facets of Bi₂₄O₃₁Br₁₀ into dominant facets would lead to higher photocatalytic activity, although the original main {213} facet has a stronger molecular oxygen adsorption ability, which illustrates that the charge separation efficiency induced by dominant/secondary facet control plays a more important role than that of O₂ adsorptive performance in improving activity.