ENGINEERING HALIDE PEROVSKITES FOR SOLAR FUEL PRODUCTION BY CO2 PHOTOCATALYTIC REDUCTION

在过去的几十年里，二氧化碳浓度一直在上升。随着可再生能源的发展，也有了新的方法来避免长期储存能力差的低能量密度电池。在这些方法中，以二氧化碳为原料光催化生产太阳能燃料最近成为一个备受讨论的研究话题。在众多已提出的光催化材料中，卤化铅钙钛矿因其优异的光电性能而显示出最大的应用前景。它们的带隙在热力学上允许水的氧化和二氧化碳的还原。然而，这被低稳定性和相对较高的电荷复合所抵消。在这项博士工作中，将找到稳定材料和提高性能的新方法。广泛的文献综述分析了不稳定性的性质和延长卤化物钙钛矿寿命的方法，重点是那些适用于光催化的方法。其次是通过异质结或添加金属电催化剂来提高性能的方法。在这项工作中，报告了与光催化有关的特征和优点，并具有相应的意义。卤化物调谐对CsPbX3的影响的早期结果显示，Cl和i之间的带隙线性移动。CsPbI3及其衍生物的不稳定性促使焦点转移到CsPbBr3， CsPbCl3和混合Cl/Br钙钛矿的分析。目前最先进的卤化铅钙钛矿光催化剂使用二维电荷传输材料和金属助催化剂。然而，目前还没有深入研究不同卤化物钙钛矿与这些添加剂之间的具体相互作用，特别是它们对选择性的影响。这项研究将提供一种系统的方法来破译卤化物掺杂、添加还原氧化石墨烯和添加银之间的任何特定相互作用，以创建大气稳定的卤化物钙钛矿光催化剂。这是气相CO2光还原技术的新发展。

CO2 levels have been on the rise for the last few decades. As moves towards renewable energy have increased, so have new ways to avoid low-energy density batteries with poor long-term storage capability. Prime amongst those ways, solar fuels produced photocatalytically from CO2 have recently become a much-discussed topic of research. From many photocatalytic materials proposed, lead halide perovskites show the most promise, due to their excellent optoelectronic properties. Their bandgap thermodynamically allows for both oxidation of water and CO2 reduction. This is, however, counterbalanced by low stability and still relatively high charge recombination. In this doctoral work, new ways of stabilising the material and improving performance will be found. An extensive literature review analyses the nature of instability and methods to extend the lifetime of halide perovskites, with a focus on those applicable to photocatalysis. This is followed by an accounting of the means to improve performance, often through heterojunctions or addition of metal electrocatalysts. A reporting of the characterisation and figures of merit relevant to photocatalysis is given in this work, with its accompanying significance. Early stage results on the effect of halide tuning on CsPbX3 showed a linear band gap shift between Cl and I. The instability of CsPbI3 and derivatives motivated the shift in focus to the analysis of CsPbBr3, CsPbCl3, and mixed Cl/Br perovskites.Current state-of-the-art lead halide perovskite photocatalysts use a 2D charge transport material and a metal cocatalyst. However, no study has focused in-depth on the specific interactions between different halide perovskites and these additives, especially on their effect on selectivity. This study will deliver a systematic approach to decipher any specific interactions between halide doping, addition of reduced graphene oxide, and addition of Ag in order to create atmosphere-stable halide perovskite photocatalysts. This serves as new development for gas-phase CO2 photoreduction.