压电光催化环境污染控制研究进展

光催化氧化技术具有操作简单、反应条件温和、清洁无二次污染等优点，已被广泛应用于各类污染物的去除。但是，低电荷载流子迁移率和电子空穴对的快速复合是限制光催化效率的关键问题。尽管通过掺杂、复合等方法能改善光催化氧化性能，但是在光催化材料的电子空穴对的分离效率仍然不高。为了解决这个问题，近年来越来越多的研究将极化电场的理论引入到光催化中，通过机械作用诱导压电材料产生的极化电场可以有效地分离光催化过程中产生的光生电子空穴对，显著提高光催化性能。本文详细介绍了压电光催化的基本原理及其影响因素，并根据不同材料体系综述了近年来压电光催化技术在污染物降解的研究进展。最后，对压电光催化的研究趋势和面临的挑战进行了展望。

Research progress on environmental pollution control by piezo-photocatalysis

Background, aim, and scope Photocatalytic oxidation technology possesses the advantages of simple operation, mild reaction conditions, clean and no secondary pollution, and has been widely used in the removal of various pollutants. However, low charge carrier mobility and fast electron hole pair recombination are the key problems which limit the photocatalytic efficiency. Although the performance of photocatalytic materials has been improved by doping and compounding, the efficiency of electron hole pair separation is still insufficient. Based on this problem, numerous researches have introduced the theory of polarization electric field into photocatalysis. The polarization electric field induced by piezoelectric materials can effectively separate photoelectron hole pairs and significantly improve photocatalysis activity. In order to summarize the recent research on the degradation of pollutants in the field of piezo-photocatalysis, this paper reviews the material system and mechanism of the degradation of pollutants in the field of piezo-photocatalysis and put forward the future research trends and challenges. Materials and methods This paper summarizes the generation mechanism of piezo-photocatalysis and its influencing factors. Besides, different piezo-photocatalysis materials for pollutants degradation are reviewed. Results The basic principle of piezo-photocatalysis is to induce the separation of photogenerated electrons and holes through the polarization electric field generated by piezoelectric materials. The main factors affecting piezoelectric photocatalysis are morphology, size, structure (doping, oxygen vacancy) and many more. The piezo-photocatalytic degradation of pollutants is mainly concentrated in the liquid phase system, because the contact between the liquid and the catalytic materials is easier to stimulate the performance of the piezoelectric material. According to the material system, the piezo-photocatalytic degradation of pollutants can be mainly divided into single material system and composite material systems. The composite material system can be further divided into piezoelectric material (no photocatalytic performance)-photocatalytic material system, metal-piezoelectric photocatalytic material system and piezo-photocatalytic material-(piezoelectric) photocatalytic material system. The main role of polarization electric field to promote the separation of bulk and surface photogenerated carriers. Discussion In this paper, the main influencing factors of piezo-photocatalysis are analyzed and the research progress of piezo-photocatalysis degradation of pollutants in recent years is summarized, which can provide theoretical reference for the development of piezo-photocatalysis in the future. The main factors affecting the performance of piezo-photocatalysis, such as morphology, size, oxygen vacancy and doping, were analyzed. These factors can not only affect the piezoelectric properties of the materials, but also affect the photocatalytic properties by affecting the semiconductor properties (such as light absorption) of the materials. The research on the degradation of pollutants by piezo-photocatalysis mainly focuses on the development of piezo-photocatalytic materials and the improvement of piezoelectric photocatalytic activity. For the single piezo-photocatalytic material system, in addition to effectively promote the separation of photogenerated carriers, the polarization electric field can also regulate the energy band structure, thus affecting the light absorption and redox capacity of the materials. For the composite material system, the coupling of piezoelectric materials and photocatalytic materials can not only effectively promote the separation of photogenerated carriers on the surface of photocatalytic materials, but also be beneficial to the recovery and application of photocatalytic materials. Furthermore, for heterojunction materials, the existence of polarization electric field can also regulate the height of metal-semiconductor and semiconductor-semiconductor interface, so as to effectively control the interface charge migration. Conclusions The research of piezo-photocatalytic degradation of pollutants mainly focuses on the development of various single and composite piezoelectric photocatalytic materials and the improvement of piezo-photocatalytic activity by regulating the structure and properties of materials. Recommendations and perspectives However, the intrinsic structure-activity relationships among the material structure, piezoelectric properties and piezo-photocatalytic properties are also needed, and the piezoelectric photocatalytic degradation is mainly used in liquid phase contaminants. Developing the reasonable material system and expanding the application of the piezo-photocatalysis also need further study and research.