Piezopotential augmented photo-and photoelectro-catalysis with a built-in electric field

压电势构建的内建电场增强光催化和光电催化（英文）

Rapid technological development and population growth are responsible for a series of imminent environmental problems and an ineluctable energy crisis.The application of semiconductor nanomaterials in photocatalysis or photoelectrocatalysis(PEC)for either the degradation of contaminants in the environment or the generation of hydrogen as clean fuel is an effective approach to alleviate these problems.However,the efficiency of such processes remains suboptimal for real applications.Reasonable construction of a built-in electric field is considered to efficiently enhance carrier separation and reduce carrier recombination to improve catalytic performance.In the past decade,as a new method to enhance the built-in electric field,the piezoelectric effect from piezoelectric materials has been extensively studied.In this review,we provide an overview of the properties of piezoelectric materials and the mechanisms of piezoelectricity and ferroelectricity for a built-in electric field.Then,piezoelectric and ferroelectric polarization regulated built-in electric fields that mediate catalysis are discussed.Furthermore,the applications of piezoelectric semiconductor materials are also highlighted,including degradation of pollutants,bacteria disinfection,water splitting for H2 generation,and organic synthesis.We conclude by discussing the challenges in the field and the exciting opportunities to further improve piezo-catalytic efficiency.

科技的飞速发展和世界人口膨胀带来一系列迫在眉睫的环境问题和能源危机.光催化和光电催化为缓解这些问题提供了绿色、经济有效的途径,已经被开发用于催化降解环境中的有机污染物、二氧化碳还原、水分解制备氢气,把生物质转化为清洁燃料,以及其它反应.通常,具有合适能带位置和带隙的半导体可以吸收太阳光,形成光生电子空穴对,然后转移到光催化剂表面,引发氧化还原反应.然而,有限的太阳光利用率和光诱导电子空穴对的高复合率阻碍了它们的工业化发展.在过去几十年里,研究人员已经制备了许多复合光催化剂,用以将光吸收范围从紫外区拓宽到可见光和近红外区域,如g-C3N4,BiVO4,Fe2O3,Ag3PO4,WO3,CdS,Sn3O4等.另一方面,还通过多种改性方法促进光生电子和空穴分离,包括表面改性、金属/非金属掺杂和异质结设计等.此外,偏压有助于电子的定向传输.因此,光电催化可以通过光照和偏置电压的协同作用,进一步增强载流子的分离.然而,高效地分离光生载流子仍然是一个巨大的挑战.近年来,通过压电和铁电效应合理地构建内建电场,以有效地增强载流子分离引起了越来越多的关注.压电体(包括铁电体、压电半导体等)是一类具有非中心对称晶体结构的材料.在机械变形或外加电场作用下,它们的正负电荷中心被分离,产生压电势.压电势可以在金属-半导体接触或半导体异质结的界面处调制载流子的传输.压电材料已被广泛用于调节压电半导体器件的性能,如晶体管、太阳能电池、发光二极管和自供电纳米系统.在光催化和光电催化中,压电半导体和具有永久极化的铁电材料通过构建内建电场在增强载流子分离方面显示出巨大的潜力.本综述总结了压电半导体和铁电材料增强的压电催化(包括光电催化和光电催化)的最新进展.首先,文章介绍了压电和铁电材料的性质以及构建内建电场促进载流子分离的机理.其次,讨论了压电势构建内建电场的具体途径,包括超声波、机械刷/滑动、热应力、水流和铁电永久极化.然后,阐明了具体的潜在应用,例如污染物的降解、杀菌消毒、用于水分解产氢和有机合成.最后,文章对该领域的挑战进行了总结,对压电催化剂未来发展的前景进行了展望.