It is known that photocatalytic activity of Ga₂O₃ on CO₂ reduction with water is enhanced by employment of a support. However, the role of the support is not understood well. We have investigated the roles of the support on the photocatalytic CO₂ reduction with using Ga₂O₃ supported by Al₂O₃ and MgAl₂O₄ as catalysts. On the supports, loaded Ga₂O₃ exhibited different crystalline phases and morphologies depending on the amount of loaded Ga₂O₃ on the supports and the specific surface areas of the supports. The larger the SSA, the more dispersedly Ga₂O₃ particles were loaded and gave higher catalytic activity. The production rates of H₂ and CO, the dominant products of the CO₂ reduction, showed different crystalline phase dependence, i.e., H₂ production was dominated on α-Ga₂O₃, while the CO production rate increased with increasing the γ-Ga₂O₃/α-Ga₂O₃ ratio and peaked at a certain γ-Ga₂O₃/α-Ga₂O₃ ratio. Two main conclusions derived are, (1) Ga₂O₃ particles dispersedly loaded as a few tens nm sized rods on the support significantly enhance the photocatalytic activity and (2) a new mechanism that on α-Ga₂O₃ water splitting is dominated and resultant H atoms reduce CO₂ adsorbed on γ-Ga₂O₃ or the boundary of the two phases.

Graphical Abstract

中文翻译：

---

Al2O3 和 MgAl2O4 载体对 Ga2O3 水还原 CO2 光催化活性的影响

已知Ga ₂ O ₃对用水还原CO _{2的光催化活性通过使用载体而增强。}然而，支撑的作用还没有得到很好的理解。我们以Al ₂ O ₃和MgAl ₂ O ₄负载的Ga ₂ O _{3为催化剂，研究了载体对光催化CO 2}还原的作用。在载体上，负载的Ga ₂ O ₃根据负载的Ga ₂ O _{3的量表现出不同的晶相和形貌}关于支撑物和支撑物的比表面积。SSA越大，Ga ₂ O ₃颗粒负载越分散，催化活性越高。_{CO 2}还原的主要产物H ₂和CO的产率表现出不同的晶相依赖性，即H ₂的产生主要以α-Ga ₂ O ₃为主，而CO的产率随着γ-Ga 2 O 3 的增加而增加。 Ga ₂ O ₃ /α-Ga ₂ O ₃比率并在某个 γ-Ga ₂ O ₃ /α-Ga ₂ O _{3处达到峰值}比率。得出的两个主要结论是：（1）Ga ₂ O ₃颗粒以几十纳米大小的棒状分散负载在载体上，显着增强了光催化活性；（2）α-Ga ₂ O ₃水分解占主导地位的新机制生成的H原子还原吸附在γ-Ga ₂ O ₃或两相边界上的CO _{2 。}

图形概要