Catalysts for photochemical carbon dioxide reduction to green fuels and chemicals

气候变化和温室效应主要与大气中一种捕获热量的分子（即CO2或二氧化碳）浓度的增加有关。作为一种应对CO2增加的战略，碳捕获和利用（CCU）在科学研究中越来越受到关注。该项目利用光催化技术将二氧化碳活化并转化为高密度的能量载体和化学前体，包括一氧化碳、醇类和酸类。为了推动二氧化碳的光催化还原，必须开发合适的半导体光催化剂。当它们与太阳光照射相互作用时，太阳的能量被转移到半导体上，产生激发态，可用于将二氧化碳还原为有价值的化学物质。本研究旨在了解半导体/催化剂的激发态和电子结构，并通过修饰描绘结构-性能关系。这项工作的目标是低温和低压过程，使用金属/金属氧化物/硫化物材料作为吸收剂和催化剂。二氧化碳还原的光化学机制很复杂，需要更多的研究来了解控制速率，选择性和产物形成途径的因素。该项目将开发稳定的光催化剂，有助于阐明光催化CO2还原的机理，并在第二阶段提高太阳能到化学转化效率。在第一阶段，紫外光吸收催化剂，如SrTiO 3（钛酸锶）将与铜（Cu）纳米粒子改性。廉价的、地球上丰富的Cu被认为是最好的候选者，这是由于其在热反应中作为MeOH（甲醇）合成的催化剂的良好记录以及其在从二氧化碳生产C2+产物的电催化中的良好记录。本论文将比较各种制备纳米铜颗粒的方法，包括电合成法、光氧化还原合成法和化学合成法。粒子催化剂的表面化学将探索使用技术，如原子层沉积和利用化学功能/反应性。我们将研究和表征催化剂-颗粒界面，并在一系列不同条件下光化学测试催化活性。这一策略将使我们更深入地了解控制产品选择性和催化剂活性的因素，并将导致基于地球丰富材料的高效光催化系统用于CO2再利用。这一具体目标绩效的影响是为解决本世纪的主要挑战之一做出巨大贡献，并支持社会和ESPRC在保护环境的同时向低碳未来过渡。因此，该项目属于EPSRC能源研究领域的福尔斯。

Climate change and the greenhouse effect are mainly related to the increasing concentration in the atmosphere of a molecule that traps heat, namely CO2 or carbon dioxide. As a strategy to address CO2 increasing levels, carbon capture and utilisation (CCU) is gaining more attention in scientific research. This project applies photochemical catalysis to activate and transform carbon dioxide into dense energy carriers and chemical precursors, including carbon monoxide, alcohols and acids.To drive the photocatalytic reduction of carbon dioxide suitable semiconducting photocatalysts have to be developed. When these interact with solar light irradiation, the sun's energy is transferred to the semiconductor creating excited states which can be used in the reduction of carbon dioxide to valuable chemicals. This research aims to understand the semi-conductor/catalyst excited states and electronic structures and delineate structure-performance relationships through modifications. The work targets low-temperature and pressure processes, using metal/metal oxide/sulfide materials as both absorbers and catalysts.The photochemical mechanisms for carbon dioxide reduction are complex and more research is needed to understand factors controlling rates, selectivity and product formation pathways. This project will develop stable photocatalysts that can help elucidate the mechanism of photocatalytic CO2 reduction and in the second stage, improve the solar-to-chemical conversion efficiencies. In the first phase, UV light-absorbing catalysts such as SrTiO3 (strontium titanate) will be modified with copper (Cu) nanoparticles. Inexpensive, earth-abundant Cu is considered the best candidate due to its strong track record as a catalyst for MeOH (methanol) synthesis in thermal reactions and its track record in electrocatalysis producing C2+ products from carbon dioxide. The thesis will compare different means to produce copper nanoparticles, including electrosynthesis, photoredox synthesis and chemical synthesis. The particle-catalyst surface chemistry will be explored using techniques such as atomic layer deposition and by exploiting chemical functionality/reactivity. Catalyst-particle interfaces will be studied and characterized and catalytic activity tested photochemically under a range of different conditions.This strategy will give us more insight into the factors that govern product selectivity and catalyst activity and will result in an efficient photocatalytic system based on earth-abundant materials for CO2 reuse. This specific target performance has the impact to give a large contribution to addressing one of the main challenges of this century and support society and the ESPRC to transition towards a low- carbon future while protecting the environment. As such, this project falls within the EPSRC Energy research area.