稳定高效α-Fe_2O_3光电化学水分解——合理的材料设计和载流子动力学  

Stable and High-efficientα-Fe_2O_3 Based Photoelectrochemical Water Splitting:Rational Materials Design and Charge Carrier Dynamics

作　　者：谢佳乐 杨萍萍 李长明 XIE Jiale;YANG Pingping;LI Chang Ming(Institute of Materials Science and Devices,Suzhou University of Science and Technology,Suzhou 215009;Faculty of Materials and Energy,Southwest University,Chongqing 400715)

机构地区：[1]苏州科技大学材料科学与器件研究院,苏州215009 [2]西南大学材料与能源学部,重庆400715

出　　处：《材料导报》2018年第7期1037-1056,共20页Materials Reports

基　　金：国家自然科学基金(21703150);国家重点基础研究发展计划(973计划;2011CB911002)

摘　　要：氢能是非常清洁的能源。发展高效、清洁和低成本的产氢装置是利用氢能的首要关键技术问题。光电化学水分解是首选的制氢技术之一。它可实现室温下直接水分解和氢氧分离,并不完全受限于太阳光的周期性波动;其产氢装置可全部由无机材料制成,有好的化学活性和使用寿命。但是,光电化学水分解技术的效率目前还无法满足实际应用的要求,特别是还不能实现长期稳定运行,存在一定的性能衰减。在各种光电极材料中,α-Fe_2O_3是非常重要且具有潜力的稳定高效的光阳极材料,已成为近年来研究的热点。α-Fe_2O_3又称赤铁矿,储量丰富,在光电化学水分解中具有良好的稳定性、低成本和良好的太阳光谱响应等优势,已成为最具应用前景的光电极材料。然而,α-Fe_2O_3固有的一些问题诸如电荷传输差、表面复合严重、电荷转移动力学缓慢等限制了其实际应用。近年来,研究者们已发展了多种多样的策略和途径,例如掺杂、纳米化、异质结和表面处理等来解决上述问题。多种金属和非金属元素如Ti、Sn、Si、S等掺杂的α-Fe_2O_3表明,异质原子的引入会降低电子的有效质量,进而提高导电性,还会影响α-Fe_2O_3的晶体扭曲和活性位点等性质。从零维、一维、二维、三维到层级结构的α-Fe_2O_3都已经成功合成;同时,纳米化也拓展到导电基底的规则阵列图案化,α-Fe_2O_3纳米化能够促进光生空穴产生和利用,已成为α-Fe_2O_3光电化学水分解性能提升的重要途径。研发的n-n型和p-n型α-Fe_2O_3异质结如α-Fe_2O_3/ZnFe2O4、p-Si/α-Fe_2O_3等已较大地提高了其光电催化水分解性能,其中异质结很大程度上促进了α-Fe_2O_3光吸收、光生电荷分离和电极过程动力学。α-Fe_2O_3表面处理如催化剂修饰、钝化层修饰、化学/电化学刻蚀、气氛处理等,则显著改善了α-Fe_2O_3电极的电荷转移、析氧动力学,并Hydrogen energy is a totally clean energy.The primary scientific and technical issue of the utilization of hydrogen energy is the development of efficient,clean,sustainable and low-cost hydrogen production technologies.Photoelectrochemical(PEC)water splitting is a preferred technology,which can directly achieve water splitting and hydrogen/oxygen separation at room temperature.PEC devices are not seriously limited by the cyclical fluctuations of sunlight,and can be made entirely of inorganic materials.Thus,PEC devices usually present high chemical activity and long lifetime.However,the efficiency of PEC devices is still not able to meet the requirements for practical applications.Moreover,the performance of PEC devices would decay with time and cannot provide long stable operations up to date.Among various photoelectrode materials,hematite(α-Fe 2O 3)is an important and promising one with excellent stability,low cost,abundant reserve,excellent solar spectrum response and high efficiency,and has become a research hotspot in recent years.However,its drawbacks of poor charge transport,high charge recombination and sluggish kinetics greatly limit its practical applications.In recent years,various approaches including doping,nanostructuring,heterojunction and surface modification/treatment have been reported.The doping ofα-Fe 2O 3 with a variety of metallic and nonmetallic elements such as Ti,Sn,Si and S shows that the incorporated heteroatoms could reduce the effective electron mass,thereby increasing the conductivity,while inducing the crystal distortion ofα-Fe 2O 3 for creating more active sites.Theα-Fe 2O 3 nanomaterials with 0D,1D,2D,3D and hierarchical structures have been successfully synthesized.Furthermore,nanostructuring arts are developed to fabricate highly conductive substrate with regular array patterns.The nanostructuredα-Fe 2O 3 can enhance the generation and utilization of holes,which is an important way to improve the PEC performance.Variousα-Fe 2O 3-based n-n and p-n heterojunctions such asα-F

关 键 词：赤铁矿 光电化学水分解 材料设计 载流子动力学 

分 类 号：O649[理学—物理化学]