Surface Engineered Nanocrystals: EPR Radical Detection of Photoactivity

表面工程纳米晶体：光活性的 EPR 自由基检测

• 批准号: EP/T013079/1
• 负责人: Emma Richards
• 金额: $ 38.74万
• 依托单位: CARDIFF UNIVERSITY
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FT013079%2F1
• 关键词: Surface; Engineered; Nanocrystals; EPR; Radical

Environmental air and water remediation by nanocrystalline semiconductor photocatalysts has become increasingly important in recent years. TiO2 remains the most popular material for these applications due to its low cost, abundance, high activity, and stability under a variety of conditions, however its wide range utilisation is restricted due to limited efficiencies, absorbing only 3% of available solar energy (in the UV region). Commercial advancements require enhanced visible-light induced quantum yields of photogenerated charge carriers. Lattice doping of TiO2 with (non)metal ions is a highly promising approach for increasing photocatalytic efficiencies through modification of bandgap and band-edge potentials, which are intricately linked to resulting surface reactions. This utilises earth-abundant metals and is a step-change from modifying oxide materials with expensive noble metals. The advent of synthetic strategies for controllable fabrication of TiO2 with specific morphologies and crystal facets has emerged as a promising way to improve charge-carrier quantum yield. This proposal aims at combining these tactics to develop a library of novel nanocrystalline materials, produced via readily scalable methodologies. This works seeks to build on our recent results. We have identified that co-doped titania catalysts (W,N-TiO2) are effective for improving the nitrate selectivity of the photocatalytic oxidation of NOx to nitrates. We have also identified specific oxygen-vacancy sites on the titania surface that act as preferential sites for catalysis. By combining these technologies, this could open new and exciting avenues in semiconductor photocatalysis for environmental remediation technologies in which the optimization of molecular oxygen reduction, together with the pollutant species to be oxidized, becomes a central element of the catalyst design without relying on the use of rare and expensive PGMs. The novel materials will be characterised by a combination of advanced spectroscopic techniques. Primarily, Electron Paramagnetic Resonance (EPR) spectroscopy will directly probe the photo-induced paramagnetic charge carriers, determining the position of highly reactive lattice sites. Advanced hyperfine structure measurements will elucidate an atomic-level structural description and access the electronic properties of lattice dopants through unique spectral fingerprints. The nature of surface reactions will subsequently be explored through state-of-the-art Attenuated Total Reflectance spectroscopy, utilising pulsed lasers to obtain reaction dynamics on fs timescales. Target applications will be selective decomposition of volatile organic compounds and nitrogen oxides (NOx), both common airborne pollutants which are damaging to human health and implicated in climate change. Our research program will have immediate impact on UK science, with academic beneficiaries within the chemical and materials sciences. The project will provide interdisciplinary training for the EPSRC PDRA and Cardiff University funded PhD student. The combination of multiple advanced spectroscopies will shed light on fundamental redox processes, which will have longer-term benefits in photovoltaics, organic synthesis and selective transformations of bulk chemicals. This New Investigator Grant will allow Dr Richards to develop an independent research programme investigating light-induced electron transfer processes, and provide a team of highly skilled researchers vital to advance her academic career.Success in this programme will combine the results of synthesis, characterization and catalytic activity to guide the rational design of selective visible-light activated semiconductor photocatalysts.

近年来，纳米晶半导体光催化剂对环境空气和水的修复变得越来越重要。由于其低成本、丰富、高活性和在各种条件下的稳定性，TiO2 仍然是这些应用中最受欢迎的材料，但由于效率有限，其广泛利用受到限制，仅吸收可用太阳能的 3%（在紫外线区域）。商业进步需要增强可见光诱导的光生电荷载流子的量子产率。用（非）金属离子对 TiO2 进行晶格掺杂是一种非常有前途的方法，可以通过改变带隙和带边电位来提高光催化效率，这与产生的表面反应有着复杂的联系。这利用了地球上储量丰富的金属，是用昂贵的贵金属改性氧化物材料的一个阶跃变化。用于可控制造具有特定形貌和晶面的 TiO2 的合成策略的出现已成为提高载流子量子产率的有前途的方法。该提案旨在结合这些策略来开发一个新型纳米晶体材料库，通过易于扩展的方法生产。这项工作旨在以我们最近的成果为基础。我们已经发现共掺杂二氧化钛催化剂（W,N-TiO2）可有效提高NOx光催化氧化成硝酸盐的硝酸盐选择性。我们还确定了二氧化钛表面上作为催化优先位点的特定氧空位位点。通过结合这些技术，这可以为环境修复技术的半导体光催化开辟令人兴奋的新途径，其中分子氧还原的优化以及要氧化的污染物种类，成为催化剂设计的核心要素，而无需依赖使用稀有且昂贵的铂族金属。这种新型材料的特点是结合了先进的光谱技术。首先，电子顺磁共振（EPR）光谱将直接探测光诱导的顺磁载流子，确定高反应性晶格位点的位置。先进的超精细结构测量将阐明原子级结构描述，并通过独特的光谱指纹获取晶格掺杂剂的电子特性。随后将通过最先进的衰减全反射光谱法探索表面反应的本质，利用脉冲激光获得飞秒时间尺度上的反应动力学。目标应用将是选择性分解挥发性有机化合物和氮氧化物（NOx），这两种常见的空气污染物会损害人类健康并与气候变化有关。我们的研究计划将对英国科学产生直接影响，化学和材料科学领域的学术受益者。该项目将为 EPSRC PDRA 和卡迪夫大学资助的博士生提供跨学科培训。多种先进光谱学的结合将揭示基本的氧化还原过程，这将为光伏、有机合成和大宗化学品的选择性转化带来长期利益。这项新研究员资助将使理查兹博士能够开发一个独立的研究项目，调查光诱导电子转移过程，并提供一支高技能的研究人员团队，这对她的学术生涯至关重要。该项目的成功将结合合成、表征和催化活性的结果，指导选择性可见光激活半导体光催化剂的合理设计。

项目成果

Heterogeneous Photocatalytic Recycling of FeX 2 /FeX 3 for Efficient Halogenation of C-H Bonds Using NaX

FeX 2 /FeX 3 的非均相光催化回收用于 NaX 高效卤化 C-H 键

• DOI: 10.1002/ange.202302994
• 发表时间: 2023
• 期刊: Angewandte Chemie
• 作者: Ye J

Inhibit the formation of toxic methylphenolic by-products in photo-decomposition of formaldehyde-toluene/xylene mixtures by Pd cocatalyst on TiO2

• DOI: 10.1016/j.apcatb.2021.120118
• 发表时间: 2021-03-16
• 期刊: APPLIED CATALYSIS B-ENVIRONMENTAL
• 影响因子: 22.1
• 作者: Wu, Qiqi;Ye, Jiani;Su, Ren
• 通讯作者: Su, Ren

Photocatalytic Abstraction of Hydrogen Atoms from Water Using Hydroxylated Graphitic Carbon Nitride for Hydrogenative Coupling Reactions

利用羟基石墨碳氮化物光催化从水中提取氢原子进行氢偶联反应

• DOI: 10.1002/ange.202204256
• 发表时间: 2022
• 期刊: Angewandte Chemie
• 作者: Zhang D