有机-无机钙钛矿光催化剂电荷传输调控及光催化分解卤化氢制氢研究

Producing solar hydrogen via photocatalytic splitting of hydrogen halide represents one feasible pathway for the conversion and storage of solar energy, which has aroused significant interests from both the scientific and industrial community. Organic–inorganic perovskites have received great attention in the past few years due to their excellent physiochemical properties. Although these kinds of materials have been extensively investigated for photovoltaics, they have been seldom used for photocatalytic hydrogen production. Based on the profound research experience in photocatalytic materials and reactions, ultra-fast and in-situ spectroscopy, imaging spectroscopy, and system integration we propose to rationally design and fine-tuning the physiochemical properties of perovskite-based (CH3NH3PbIxBryClz et al.) photocatalytic systems through band gap engineering, interface engineering, and coupling engineering. With these synergetic efforts, the key reaction steps including the light absorption properties, the charge separation and transfer efficiencies, and the surface catalysts are anticipated to be greatly improved, which will eventually leads to highly active and stable hydrogen production from hydrogen halide splitting. Moreover, this project aims to illustrate the fundamental mechanism related with the separation and transfer of photogenerated charges on perovskite nanocrystalls with advanced spectroscopy, which will provide a good basis for using perovskite-based photocatalysts for solar fuel production.

光催化分解卤化氢制氢是太阳能转化和存储的一条潜在途径，相关研究具有重要的科学意义和应用背景。近几年，有机-无机钙钛矿材料由于其优异的光电物理性质在太阳能电池等领域受到广泛关注，但基于该类材料进行光催化制氢的研究却刚刚起步。本项目将基于研究团队在光催化材料、光催化反应、光催化耦合系统、超快原位光谱表征等方面的积累和优势，拟通过界面工程、能带工程、系统耦合工程等策略，对基于CH3NH3PbIxBryClz等有机-无机钙钛矿材料的半导体光催化反应系统进行理性设计、调变和优化，实现高效太阳能吸收、高效光生电荷的分离和输运、高效表面催化反应等关键步骤，进而实现高效、稳定的光催化分解卤化氢制氢反应。此外，本项目还将采用荧光光谱、超快原位光谱、成像光谱等从微观角度揭示钙钛矿纳米光催化剂在反应过程中光生电子、空穴分离及传输机制，为利用钙钛矿材料进行人工光合成燃料的生产提供理论和技术支撑。

半导体光催化制氢是实现太阳能转化和存储的一种潜在途径。有机-无机钙钛矿半导体材料具有优异的光电物理性质，近几年在该领域受到广泛关注。但受限于严重的光生电荷复合，基于有机-无机钙钛矿材料的光催化制氢系统效率仍处于较低水平，亟待发展提升其光生电荷传输的策略和手段。在本项目中，项目团队提出并实现了多种新型调控钙钛矿光生电荷传输的策略，阐明多种了影响二维、三维、二维-三维混合钙钛矿光生电荷传输的微观机制，并在多个体系实现了高效光催化分解卤化氢制氢反应。项目五项代表性研究成果如下：（1）以苯胺基团为二维有机-无机钙钛矿的层间阳离子，在国际上首次报道在二维有机-无机钙钛矿材料中实现光催化制氢反应，阐明了苯胺基团链长影响光生电荷传输的微观机制。（2）以不同位F取代的苯乙胺为二维有机-无机钙钛矿的层间阳离子，发现采用对位F取代苯乙胺时，二维有机-无机钙钛矿材料内建电场强度显著增强，进而实现高效光生电荷传输和光催化产氢；（3）首次以二维-三维混合有机-无机钙钛矿为光催化剂，通过维度调变，调控钙钛矿的光电物理性质，进而优化其光生电荷传输；（4）、首次提出并实现有机-无机钙钛矿光催化剂表面双功能化调控策略，同时实现钙钛矿表面缺陷钝化和无定型高性能助催化剂担载，进而实现高效光催化产氢反应；（5）、以PMA2PbI4二维有机-无机钙钛矿材料为模型材料，在真实反应条件下原位观测光催化产氢反应，首次发现PMA2PbI4微米片的侧边是光催化反应的还原活性位点。目前项目负责人作为通讯/第一作者已在Angew. Chem. Int. Ed.（1）、Adv. Energy Mater.（1）、Nano Energy（2）、J. Mater. Chem. A（1）和Small（1）期刊发表论文 6篇，另有3篇高质量研究工作待整理发表。总之，本项目已完成预定目标，将为利用有机-无机钙钛矿材料高效光催化制氢提供理论和策略支持。