Frustrated Lewis pairs (FLPs) created by sterically hindered Lewis acids and Lewis bases have shown their capacity for capturing and reacting with a variety of small molecules, including H₂ and CO₂, and thereby creating a new strategy for CO₂ reduction. Here, the photocatalytic CO₂ reduction behavior of defect‐laden indium oxide (In₂O_3−x(OH)_y) is greatly enhanced through isomorphous substitution of In³⁺ with Bi³⁺, providing fundamental insights into the catalytically active surface FLPs (i.e., InOH···In) and the experimentally observed “volcano” relationship between the CO production rate and Bi³⁺ substitution level. According to density functional theory calculations at the optimal Bi³⁺ substitution level, the 6s² electron pair of Bi³⁺ hybridizes with the oxygen in the neighboring InOH Lewis base site, leading to mildly increased Lewis basicity without influencing the Lewis acidity of the nearby In Lewis acid site. Meanwhile, Bi³⁺ can act as an extra acid site, serving to maximize the heterolytic splitting of reactant H₂, and results in a more hydridic hydride for more efficient CO₂ reduction. This study demonstrates that isomorphous substitution can effectively optimize the reactivity of surface catalytic active sites in addition to influencing optoelectronic properties, affording a better understanding of the photocatalytic CO₂ reduction mechanism.

中文翻译：

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量身定制In2O3-x（OH）y的表面受阻路易斯对，以Bi3 +同质取代In3 +进行气相非均相光催化还原CO2

由位阻路易斯酸和路易斯碱产生的沮丧路易斯对（FLP）已显示出它们具有捕获各种小分子（包括H ₂和CO ₂）并与之反应的能力，从而创造了一种新的CO ₂还原策略。在这里，通过用Bi ³⁺同构取代In ³⁺，大大提高了负载有缺陷的氧化铟（In ₂ O _{3− x}（OH）_y）的光催化CO ₂还原行为，从而提供了对具有催化活性的表面FLP的基本认识。 （即，在OH···In）和实验观察到的CO生成速率与Bi ³⁺取代水平之间的“火山”关系。根据在最佳的Bi密度泛函理论计算³⁺取代水平，6S ²电子对的Bi ³⁺与在邻近的在氧杂交的 OH路易斯碱位点，导致轻度增加路易斯碱度而不影响的路易斯酸性附近的刘易斯（Lewis）酸性地点。同时，Bi ³⁺可以充当额外的酸位，从而使反应物H ₂的杂化裂解最大化，并产生更多的氢化物，从而获得更有效的CO ₂减少。这项研究表明，同构取代不仅可以有效地优化表面催化活性位的反应性，而且还可以影响光电性能，从而使人们对光催化还原CO _2的机理有了更好的了解。