Abstract:

Photocatalytic conversion of carbon dioxide (CO₂) into solar fuel or chemicals is considered to be one of the effective ways to alleviate the energy crisis and greenhouse effect. In order to improve the activity and selectivity of CO₂ photoreduction, the structure design and performance regulation of photocatalysts is critical. Among various photocatalysts, two-dimensional layered double hydroxides (LDHs) exhibit fascinating properties in the field of photocatalysis due to their adjustable composition and ratio of cations on the host layer, and exchangeable capability of interlayer guest anions. Considering the rapid development of LDHs photocatalysts, this review presents the research progress of structural regulation of LDHs for enhancing photocatalytic CO₂ reduction. Firstly, the mechanism of photocatalytic CO₂ reduction and the structural characteristics of LDHs photocatalysts are briefly introduced. Secondly, the electronic structure and geometric structure of LDHs photocatalysts are reviewed in terms of defect engineering, morphology and size regulation and heterojunction structure construction. The performance of the optimized LDHs is improved by enhancing light absorption, electron hole separation and migration, and surface reduction, especially by adjusting the structure of the active site to reduce the reaction energy barrier. Facing the challenges of LDHs applications for photocatalytic CO₂ reduction, we finally proposed related insights and strategies for design and fabrication of LDHs, the investigation of reaction mechanism and the modification of multi-carbon products.

Key words: carbon dioxide, reduction, catalyst, photochemistry

摘要：

光催化转化二氧化碳（CO₂）为太阳能燃料或化学品被认为是缓解能源危机和温室效应的有效途径之一。为提高CO₂光还原产物的活性、选择性，光催化剂的结构设计和性能调控至关重要。在众多光催化剂中，二维层状双金属氢氧化物（layered double hydroxides，LDHs）又称水滑石，因其层板阳离子组成及比例可调变、层间客体阴离子可交换等特性在光催化领域展现出广阔的应用前景。本文综述了LDHs结构调控策略用于强化光催化CO₂还原的研究进展。首先介绍了光催化CO₂还原的机理和LDHs光催化材料的结构特征；然后重点总结了基于缺陷工程、形貌尺寸调控和异质结构筑等策略调控LDHs光催化剂的电子结构及几何结构，优化后的LDHs通过增强光吸收、电子空穴分离迁移能力及表面还原反应能力，尤其是通过调控活性位结构降低反应势垒，实现了性能强化；最后，基于LDHs光催化剂在CO₂还原领域存在的挑战，包括LDHs的设计构筑、机理探索以及多碳产物的调控提出了相关解决思路和策略。

关键词: 二氧化碳, 还原, 催化剂, 光化学