网粒体仿生制备复合纳米结构光电极材料及分解水性能研究

The direct conversion of solar energy into hydrogen energy by semiconductor photoelectrodes is one of the effective ways to solve the energy crisis and environmental pollution problems. Many devices with excellent performance can be designed by studying the relationship between structure and function in nature. This project plans to design and fabricate three-dimensional biomimetic brochosomes composite photoelectrodes by colloidal microsphere self-assembly technology combined with atomic layer deposition and electrochemical deposition technology, and apply them to photoelectrochemical (PEC) water splitting. The structure design of brochosomes photonic crystals is used to improve the efficiency of light capture, semiconductor heterojunctions to promote the separation and transmission efficiency of photo-induced carriers, and co-catalysts to enhance the kinetic rate of water oxidation. It is expected to develop efficient PEC water splitting materials and devices through bionic structure design. Through accurate and controllable preparation of brochosomes structure, the intrinsic relationship between brochosomes structure parameters and optical properties and PEC water splitting performance was established. The dynamics of structure regulation, heterojunction design and co-catalyst for improving photo-induced carrier generation, transmission and recombination were systematically studied from experimental and theoretical aspects through a series of spectral methods, finite element simulation and first principles calculation. The process reveals the physical essence that affects the efficiency of PEC water splitting, and provides theoretical guidance for exploring the application of bionic brochosomes structure in energy, catalysis, optoelectronics and other fields.

利用半导体光电极将太阳能直接转换成氢能是有效解决能源危机和环境污染问题的途径之一。通过研究自然界中结构与功能的关联可设计诸多具有优异性能的器件。本项目计划通过胶体微球自组装技术结合原子层沉积和电化学沉积技术设计制备三维仿生网粒体复合光电极并应用于光电化学分解水制氢。利用网粒体光子晶体结构设计提升光俘获效率，半导体异质结促进光生载流子分离和传输效率，助催化剂提升水氧化动力学速率，期待通过仿生结构设计开发高效光解水制氢材料与器件。通过网粒体结构的精确可控制备，建立网粒体结构参数与光学特性和光解水性能的内在联系，通过一系列光谱研究手段和差分有限元模拟及第一性原理计算从实验和理论两方面系统研究结构调控、异质结设计结合助催化剂改善光生载流子产生、传输和复合的动力学过程，揭示影响光解水制氢效率的物理本质，为探索仿生网粒体结构在能源、催化、光电等领域的应用提供理论指导。

随着传统化石能源危机及环境污染问题被持续关注，开发清洁、可再生能源迫在眉睫。氢能具有能量密度高、清洁、可再生等优点，被认为是一种十分有前途的能源形式，而利用太阳能分解水制氢，将太阳能转换成化学能可同时解决能源危机和环境污染问题。自1972年Fujishima和Honda首次报道TiO2受光照分解水产氢以来，利用半导体光电极驱动太阳能水解反应制取氢气受到广泛关注。低光捕获效率和高载流子复合率是制约光电化学分解水效率的主要瓶颈。为了解决这些问题，当前研究主要通过光电极纳米结构化设计、异质结调控、元素掺杂、表面修饰等手段提高光电极的光电化学(PEC)性能。近年来，仿生纳米材料渗透到生命、信息和工程等多个方向，成为一种新型功能性材料，其特殊的表面性能对于人工界面工程有极大的推动作用。 . 本项目系统研究了仿生纳米结构BiVO4基半导体光阳极的制备以及光电化学水解性能，主要研究内容如下：通过胶体微球模板法、电化学沉积和原子层沉积(ALD)技术设计制备了一种三维TiO2/WO3/BiVO4仿生网粒体结构光阳极，用于太阳能光电化学分解水制氢。三维导电FTO(F：SnO2)玻璃表面生长TiO2/WO3仿生网粒体结构作为骨架，进一步电化学沉积BiVO4光吸收层，明显改善了仿生网粒体结构的PEC性能，模拟太阳光辐照(AM 1.5 G：100 mW·cm-2)，最大光电流密度4.27 mA·cm-2(1.23 V vs. RHE)。PEC分解水性能改善归功于三维网粒体结构可提供较高的比表面积以及WO3/BiVO4异质结快速的载流子传输特性，FeOOH/NiOOH表面助催化层也提高表面反应动力学特性和载流子分离效率。