光电催化分解水的光阳极改性策略（英文）

发布时间：2018-11-22 10:24

【摘要】：光电催化分解水系统能直接将收集的电子与空穴用于分解水,将太阳能转化成了具有高能量密度的氢气,是一种集太阳能转化和储存于一体的高效绿色能源系统。光阴极和光阳极串联要求其在工作状态下两电极通过的总电流必须一致,低效率的一端将会限制整个体系的反应速度,因此对于光阳极材料的系统研究具有十分重要的意义。理论预测表明,基于部分可见光响应的半导体光阳极能带间隙计算得到的极限太阳能制氢转化效率达到了15%。但实际上由于光催化的整个过程是一个多步反应,各个步骤上发生的光生载流子的复合和损失导致了目前合成的相关电极材料的转换效率远低于理论水平。一般可以认为光催化过程包括五个步骤:光电极材料中电子的光致激发而产生电子-空穴对、电子和空穴由于能带弯曲的反向分离和传递、电子(或空穴)通过半导体-电解液界面的注入水中析氢(或析氧)、载流子的复合以及反应物和产物的传质过程。由于这些过程的进行效率与电极材料的本质特性和性能密切相关,为了评估材料性能而引入的一些效率指标往往和这几个步骤相对应。本文首先简要介绍了评价光阳极的一些效率计算以及它们与上述各个步骤的内在联系。最后,在前人和最近的研究基础上总结了几种对光阳极材料的主要提升策略,包括形貌控制、元素掺杂、异(同)质结和表面修饰等改性方法,对这些改性方法和各步骤效率之间的联系作了简单的介绍。
[Abstract]:Photocatalytic water decomposition system can directly use the collected electrons and holes to decompose water and convert solar energy into hydrogen with high energy density. It is an efficient green energy system which integrates solar energy conversion and storage. The total current of photoanode and photoanode in series must be the same under the working condition. The low efficiency end will limit the reaction speed of the whole system, so it is very important to study the system of photoanode material. The theoretical prediction shows that the limited conversion efficiency of hydrogen production from solar energy based on the band gap calculation of semiconductor photoanode based on partial visible light response is up to 15. However, in fact, the whole process of photocatalysis is a multi-step reaction, and the recombination and loss of photogenerated carriers in each step result in the conversion efficiency of the related electrode materials synthesized at present is much lower than the theoretical level. The photocatalytic process is generally considered to consist of five steps: the photoexcitation of electrons in photopolar materials produces electron-hole pairs, and electrons and holes are separated and transmitted in opposite directions due to the bending of energy. Electron (or hole) hydrogen evolution (or oxygen evolution), carrier recombination, and mass transfer of reactants and products through the semiconductor-electrolyte interface in the injected water. Because the efficiency of these processes is closely related to the essential properties and properties of the electrode materials, some efficiency indicators introduced to evaluate the properties of the materials often correspond to these steps. In this paper, some efficiency calculations for evaluating photoanode and their internal relation with the above steps are introduced briefly. Finally, on the basis of previous and recent studies, several strategies for improving photoanode materials are summarized, including morphology control, elemental doping, different (identical) bonding and surface modification methods, etc. The relationship between these modification methods and the efficiency of each step is briefly introduced.
【作者单位】：中山大学化学学院;香港科技大学化学系;
【基金】：supported by the National Science Fund for Distinguished Young Scholars,China(21425627) National Natural Science Foundation of China(21461162003,21476271) Natural Science Foundation of Guangdong Province,China(2014KTSCX004,2014A030308012)~~
【分类号】：O643.36

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