Photocatalytic CO₂ reduction suffers from the weakness of high energy barrier, low efficiency and poor selectivity. Exploring effective strategy to enhance the adsorption and activation behavior of CO₂ molecules is an alternative approach to boost CO₂ photoreduction performance. In this work, abundant oxygen vacancies (V_O) are introduced onto Bi₂Sn₂O₇ nanoparticles (NPs) by decreasing their size down to about 4 nm. The V_O mediated NPs exhibit a tremendous 8.1 times enhanced performance than the bulk counterpart towards CO₂-to−CO conversion in pure water. This is attributed to fast charge diffusion and abundant Vo for effective CO₂ adsorption and activation in the ultra-small nanoparticles. The V_O mediated Bi₂Sn₂O₇ NPs have electron back donation nature and optimized electronic structure for effectively activating CO₂, which were demonstrated by density functional theory calculations. During the reduction process, the Vo can effeciently stabilize the COOH* intermediates, and also lower the energy barrier of CO desorption determining step.

光催化还原CO ₂的缺点在于高能垒，低效率和选择性差。探索增强CO ₂分子吸附和活化行为的有效策略是提高CO _2光还原性能的另一种方法。在这项工作中，通过将Bi ₂ Sn ₂ O ₇纳米颗粒的尺寸减小到大约4 nm ，将大量的氧空位（V _O）引入到Bi ₂ Sn ₂ O ₇纳米颗粒（NPs）上。V _O介导的NPs表现出比大量CO ₂强大的8.1倍。在纯水中的二氧化碳转化为二氧化碳。这归因于电荷的快速扩散和丰富的Vo，可有效吸收超小纳米颗粒中的CO ₂并活化。由V _O介导的Bi ₂ Sn ₂ O ₇ NPs具有电子返给性质和有效激活CO _2的优化电子结构，这通过密度泛函理论计算得到证明。在还原过程中，Vo可以有效稳定COOH *中间体，并降低CO解吸确定步骤的能垒。