双结型钙钛矿光伏电池/双功能催化剂无辅助全解水性能研究

Energy and environment are the key issues which restrict the further development of the society, and solar energy powered water splitting is one of the most promising techniques to reduce our dependence on fossil fuels. This project intends to build a photovoltaic cell-electrolyser system and conduct the optimization from both sides including the output of photovoltaic cell (supplier side) and the driving requirement of catalyst (consumer side). On one hand, the perovskite/perovskit tandem solar cell will be realized through energy band engineering for accurate regulation of perovskite’s band gap, as well as the matching optimization of both perovskite light absorption layers, in order to improve the utilization efficiency of the solar light and enhance the solar-to-hydrogen efficiency. Thus, the thermodynamics and kinetics barriers can be overcome during the water splitting process. This is expected to reveal the regulation rules for the output of tandem solar cells with such design on the band gap matching. On the other hand, based on the earth abundant element, the bifunctional catalyst NiCo layered double hydroxide (NiCo-LDH) will be realized through material design and suface/interface engineering in order to reduce the overpotential requirement and squeeze cost. This is expected to reveal the synergistic effect of two kinds of metal atoms in the NiCo-LDH. Moreover, this project aims to solve the matching problem between the output of the tandem solar cell and the driving requirements of electrocatalyst in order to further optimize the solar-to-hydrogen efficiency, and thereby clarify the charge transfer mechanism in the unassisted overall water splitting process and the working mechanism of such PV-electrolyser system. This research project will provide experimental and theoretical guidance for the development and application of high efficient and cost effective solar energy powered water splitting.

能源与环境是制约社会发展的难题，利用太阳能解水制氢极有可能缓解对化石燃料的依赖。本项目拟构建光伏电池-电催化剂光解水系统，从光伏电池输出（供给侧）与电催化剂驱动需求（消费侧）两角度同时出发，一方面通过能带工程精确调控钙钛矿的带隙，匹配优化双吸光层吸收光谱范围，实现双结钙钛矿光伏电池的设计构筑，提升电池输出性能，以克服实际解水中的热力学与动力学势垒，揭示双吸光层带隙匹配设计对电池输出性能的调控规律；另一方面通过材料设计与表界面调控开发基于地球富量元素的NiCo层状双氢氧化物双功能催化剂，降低过电位需求，阐明双金属元素相对含量、形貌结构、表面缺陷对催化性能的调控机制，探讨双金属原子间的协同作用。同时，解决双结型电池输出与电催化剂驱动需求间的匹配问题，优化光转氢效率，揭示无辅助全解水过程中的电荷转移机制及光解水系统的工作机理，为设计开发高效、廉价的光解水系统并推动其走向产业化提供实验和理论基础。

随着全球性能源短缺和环境恶化问题的日益突出，能源和环境问题已成为目前人类面临和亟待解决的重大难题，研究新的替代能源和清洁环境技术备受关注。通过光催化分解水将太阳能转化为高能量密度的氢气有望在减轻人类对化石能源依赖的同时减少CO2的排放，实现人类社会的碳中和。基于此，本项目提出了“A位管理思想”、“路易斯碱延缓生长”、“双极性钝化”等一系列高质量杂化钙钛矿合成的新方法，发展了适用于电子束敏感杂化钙钛矿材料的开尔文探针力显微镜、导电原子力显微镜等表征新技术，对半导体材料中光子吸收、激子产生与分离、载流子的输运与复合等行为进行了更为深入的理解，并实现了光生载流子行为与相稳定性的高效调控，结合组分工程、界面工程以及能带工程等策略，构筑了光学带隙可调、开路电压可控、高效率、高稳定性的单结、双结型钙钛矿光伏电池。此外，发展了催化剂原子级、纳米级缺陷精准制造策略，提出了“单原子空位缺陷催化剂”概念，推动了催化剂缺陷工程向单原子级精准调控的进步。在钙钛矿、尖晶石等晶体结构催化体系中发展了组分精细调控诱导的原子空位缺陷引入策略，建立了原子缺陷主导的催化剂服役动态重构机制。发展液相刻蚀方法精准制造纳米孔洞缺陷方法，突破了催化剂表面反应离子输运动力学行为制约。开辟了“供给侧”与“消费侧”协同、联动调控催化性能的新理念与普适性策略，研制出镍钴层状双金属氧化物高性能双功能解水催化剂。基于以上研究，构建了光伏电池-电解槽光解水制氢系统，获得了中国计量科学研究院认证的18.01%的光转氢效率。本项目的研究为高质量杂化钙钛矿材料及其光伏电池技术，高催化活性催化剂的研制，以及设计开发高效、廉价的光解水系统并推动其走向产业化提供实验基础和理论依据。