基于可见光催化的光化学反应池及其分解水同时产氢产氧的研究

This project provides a novel composite system for spontaneous photochemical water splitting by using the photoexcited holes of n-type semiconductor photoanode for water oxidation and electrons of p-type semiconductor photocathode for water reduction, which overcomes the current photocatalysts drawbacks of weak reduction ability of photoexcited electrons, low-efficient spontaneous hydrogen generation, the need of sacrifice agent or external bias, and incompetent for simultaneous generation oxygen and hydrogen, etc.. The efficient photoelectrochemical cell for water splitting spontaneously under light illumination is possible on the basis of energy level difference of semiconductor materials, in which the photoanode provides a negative bias for photocathode and simultaneously is applied a positive bias from it. This project also provides the preparation of suitable, stable, efficient and visble-light responsive n-type semiconductor photoanode (Co-Pi/WO3/W) and p-type semiconductor photocathode (nanowires Cu2O/Cu), the design of photoelectrochemical cell, and the mechanism of oxygen and hydrogen evolution.The preliminary results has confirmed that the photoelectrochemical cell has superior performance for spontaneous water spilting to simultaneous generation oxygen and hydrogen.

针对现有光催化剂分解水制氢时，光生电子还原能力低（导带能级偏高）、产氢能力差、常需添加牺牲剂或提供偏电压、不能同时产氢产氧等问题，课题提出了可见光催化分解水研究的新思路：依据可见光响应的n-型和p-型半导体的能级差异，设计可见光催化的复合光化学系统，通过价带能级高的n-型半导体产生光生空穴氧化水产氧，通过导带能级低的p-型半导体产生光生电子还原水产氢，同时还利用所选n-型半导体导带能级明显低于p-型半导体价带能级的特征，让光阴极自发地为光阳极提供正偏压，光阳极又自发地为光阴极提供负偏压，由此实现可见光催化下的高效、自发分解水同时产氢产氧的目的。课题提出了符合能级要求的、稳定、高效、可见光响应的n-型半导体（Co-Pi修饰的钨基WO3纳米片薄膜）和p-型半导体（铜基Cu2O纳米线薄膜）材料以及光化学池设计、产氧产氢性能与机制研究的方案。初步试验结果表明该化学池具有优异的分解水产氢产氧性能。

项目针对现有光催化分解水制氢存在的光生电子还原能力低、产氢能力差、需添加牺牲剂或提供偏电压、不能同时产氢产氧等问题，开展了自偏压光催化分解水产氢产氧研究。项目研制了系列可见光响应的、具有良好光生电荷分离、传输与催化性能的光阳极材料，包括利用过氧钨酸还原制备WO3纳米片阵列薄膜，利用阳极氧化方法制备钨基WO3纳米孔薄膜并进而制备了钨基WO3/BiVO4异质结薄膜，利用电沉积的方法制备纳米α-Fe2O3薄膜等，并对相关材料进行了磷酸钴修饰。项目通过设计具有3D纳米线结构的Cu2O/ZnO异质结材料提升了Cu2O光阴极材料的稳定性；项目优化了Pt/PVC光阴极材料的性能，在此基础上构建了包括WO3/W-Pt/PVC、Bi2S3/TNA-Pt/PVC等系列自偏压光电化学池，实现了可见光催化下自发分解水产氢、产氧。项目在Nano Energy等发表了10篇SCI论文，为光催化分解水制氢提供了新思路。