光激发电荷在光催化氧化还原反应中的全利用  

Overall Utilization of Photoexcited Charges for Simultaneous Photocatalytic Redox Reactions

作　　者：王中辽 汪静 张金锋[1] 代凯[1] Zhongliao Wang;Jing Wang;Jinfeng Zhang;Kai Dai(Key Laboratory of Green and Precise Synthetic Chemistry and Applications,Ministry of Education,Anhui Province Key Laboratory of Pollutant Sensitive Materials and Environmental Remediation,School of Physics and Electronic Information,Huaibei Normal University,Huaibei 235000,Anhui Province,China)

机构地区：[1]淮北师范大学,绿色和精准合成化学及应用教育部重点实验室和污染物敏感材料与环境修复安徽省重点实验室,物理与电子信息学院,安徽淮北235000

出　　处：《物理化学学报》2023年第6期4-25,共22页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(22278169,51973078);安徽省杰出青年基金(1808085J14);安徽省教育厅重大项目(KJ2020ZD005)资助项目。

摘　　要：光催化转化CO_(2)为碳氢燃料,分解水产氢,选择性有机合成,还原N_(2)为NH_(3),降解毒害的有机污染物等对解决能源环境问题有重要意义。早在1972年,研究者利用TiO_(2)通过光催化实现了全面分解水产氢和产氧。由于低的可见光利用率,严重的载流子复合和过高的水氧化能垒导致光催化全面水分解的效率极低。由于氢相对于氧更具有经济价值,因此牺牲剂辅助的光催化产氢被大量研究。由于牺牲剂可以快速的消耗光生空穴,有效降低了氧化端的能垒,光催化产氢的效率相比于光催化水分解的效率提高了3–4个量级。然而,牺牲剂的使用不仅导致了光生空穴的浪费,成本的提高,还导致了潜在的环境问题。近些年,研究者通过将光催化还原反应和光催化氧化反应结合在一起实现了电子空穴的全面利用,并改进了氧化和还原的效率。同时,电子空穴的全面利用也有效的促进了电荷的分离并提高了催化剂的稳定性。然而,由于全面氧化还原的设计难度大,反应过程复杂,因此光催化全面氧化还原的机理尚不够明确,仍然需要大量的探索。在这篇综述中,首先从光捕获、光激发电荷分离、氧化还原反应的热力学和动力学过程等角度讨论了光催化的基本原理。然后根据不同的光催化氧化反应和光催化还原反应的耦合,比如光催化整体水分解、光催化产H_(2)与有机氧化耦合、光催化CO_(2)还原与有机氧化耦合、光催化产H_(2)O_(2)与有机氧化耦合、光催化N_(2)还原与N_(2)氧化耦合、光催化有机还原与有机氧化耦合等光催化全面氧化还原反应进行了系统分类。随后,从光催化材料的设计、反应条件、反应物和产物的多样性等方面详细考虑了光催化氧化还原反应的设计要点。此外,通过功函数、电子密度差、Bader电荷、吸附自由能的变化,讨论了密度泛函理论(DFT)计算在揭示光激发电荷转The photoconversion of CO_(2) to carbon-containing fuels,splitting water into H_(2),selective organic synthesis,reduction of N_(2) to NH3,and hazardous organic contaminant degradation represent feasible schemes for solving environmental and energy issues.In 1972,TiO_(2) was applied for decomposing water into H_(2) and O_(2) via photocatalysis.Owing to its the low visible-light utilization,fast charge recombination,and high energy barrier for water oxidation,overall photocatalytic water-splitting efficiency is extremely low.Because H_(2) is more economically valuable than O_(2),sacrificial agent-assisted photocatalytic H_(2) evolution has been extensively investigated.Because the sacrificial agent can quickly consume photoexcited holes and effectively reduce the water oxidation energy barrier,photocatalytic H_(2) evolution efficiency can be increased by 3–4 orders of magnitude compared to photocatalytic water splitting.However,the overuse of sacrificial agents contributes to wasted photoexcited holes and expensive processes,while presenting potential environmental issues.Recently,overall charge utilization and improved redox efficiency have been achieved by coupling photocatalytic reduction with oxidation reactions.Moreover,overall charge utilization can boost charge separation and increase photocatalyst durability.However,the photocatalytic mechanism of the overall redox reactions remains unclear,owing to the complex reaction processes and design difficulties.Herein,the basic principles of photocatalysis are discussed from the perspective of light harvesting,photoexcited charge separation,thermodynamics,and redox reaction kinetics.Photocatalytic redox reactions,including overall water photodecomposition,photocatalytic H_(2) evolution coupled with organic oxidation,photocatalytic CO_(2) reduction coupled with organic oxidation,photocatalytic H_(2)O_(2) production coupled with organic oxidation,photocatalytic N_(2) reduction coupled with N_(2) oxidation,and photocatalytic organic reduction coupled with organic ox

关 键 词：光催化 整体氧化还原反应 太阳能利用 电荷分离 协同效应 

分 类 号：O643[理学—物理化学]