表面等离激元Au-Cu纳米催化剂的冷等离子体制备及其可见光催化氧化脱除VOCs反应研究

Photocatalytic oxidation of volatile organic compounds (VOCs) into CO2 and H2O can be realized under mild reaction conditions, showing very promising applications for VOCs removal from indoor air. Development of novel visible light photocatalysts to enhance reaction performance and reduce catalyst cost is the research core of VOCs photocatalytic removal. In this proposal, we focus on preparation of plasmonic Au-Cu nanocatalysts using cold plasma and their application to visible light photocatalytic removal of VOCs. To prepare the high efficient and cheap plasmonic Au-Cu nanocatalysts，Au-Cu precursors are deposited first on semiconductor supporter, and then cold plasma is adopted on catalysts treatment to activate the Au-Cu nanocatalysts. In situ diagnosis by optical emission spectrum and on-line monitoring with FT-IR and MS are employed to study the process of cold plasma treatment with the purpose of unravelling the preparation mechanism. Furthermore, the prepared plasmonic Au-Cu nanocatalysts are used to oxidize the typical VOCs-formaldehyde under visible light irradiation. In-situ DRIFT characterization and kinetics study on visible light photocatalytic removal reaction is used to disclose the mechanism of visible light photocatalytic removal for VOCs. The dynamic characterization on Au-Cu nanocatalysts in photocatalytic reactions and physicochemical characterization of the catalysts pre- and post-reaction are combined to understand the intrinsic relationship between structure of Au-Cu nanocatalysts and their visible light photocatalytic activity, and clarify the performance enhancement mechanism for plasma prepared catalysts. We wish breakthroughs in high efficient plasmonic photocatalysts controllable preparation by cold plasma can be achieved through this project, and the results could also provide reference for related researches in the field of VOCs visible light photocatalytic removal.

光催化氧化法可在温和反应条件下将挥发性有机物（VOCs）氧化为二氧化碳和水，在室内VOCs脱除方面表现出极具潜力的应用前景。研制新型可见光催化剂来增强光催化性能和降低催化剂成本是VOCs光催化氧化脱除研究的核心。本项目拟以表面等离激元Au-Cu纳米催化剂的冷等离子体制备及其可见光催化氧化脱除VOCs反应为研究着力点，沉积/负载Au-Cu前驱体，以冷等离子体制备高效廉价Au-Cu纳米催化剂，基于等离子体的在线监测与原位诊断，探讨相关制备机理。将Au-Cu纳米催化剂用于VOCs可见光催化氧化脱除，综合反应动力学与原位/非原位表征研究，揭示其光催化反应机理；通过对反应条件下催化剂原位动态表征，深化对催化剂构效关系本质的认知，阐明冷等离子体制备对催化剂光催化性能与稳定性的增强机制。本项目力争在高效表面等离激元光催化剂冷等离子体可控制备方面取得突破，成果可为VOCs可见光催化氧化脱除研究提供借鉴。

可见光催化技术能将室内空气污染物（VOCs、CO等）氧化为CO2和H2O，在室内空气污染治理方面极具应用潜力。光催化剂多数对紫外光有响应，仅部分光催化剂能在可见光辐照下展现一定光催化活性，但它们的性能普遍不高且造价昂贵。研制新型可见光催化剂以增强光催化性能和降低催化剂成本是将可见光催化技术用于室内空气治理的关键所在。.本项目采用大气压冷等离子体技术活化表面等离激元Au基复合纳米催化剂，并将其用于可见光催化氧化反应；研究了等离子体活化Au基纳米催化剂的机理，揭示了等离子体活化增强Au基纳米可见光催化剂性能的内在机制：.(1)构建AuAg纳米催化剂，利用氧等离子体活化催化剂，有效调控金属纳米粒子与载体间的界面特性。可见光辐照下，氧等离子体活化的AuAg纳米催化剂可将CO氧化反应速率由传统Au纳米催化剂的6.3 mol g-1 h-1提升至23.1 mol g-1 h-1。.(2)采用一步法构建了AuCu纳米催化剂，借助氧等离子体活化AuCu纳米催化剂，将催化剂用于可见光辐照下的CO 及甲醛氧化反应。结果表明，与传统Au纳米催化剂相比，该AuCu纳米催化剂需其一半Au负载量可获得相同的催化活性，且其稳定性更高。.(3)氧等离子体可在纳米催化剂表面建立库伦场，重构载体表面的活性组分，增强组分间相互作用，促进合金粒子形成，并使催化剂获得高密度的配位不饱和活性位点；同时，氧等离子体中含有的氧物种还能促进催化剂表面活性氧的形成。.(4)对于室内空气污染物的光催化氧化反应而言，可见光辐照下产生的热电子在催化界面的传递是速控步骤。经氧等离子体活化的Au基纳米催化剂分散度高，可形成更多催化界面，拥有大量具有超高催化活性的配位不饱和位点，含有的第二金属既能形成合金粒子来增强对可见光的吸收，还可借助其在界面处的金属氧化物增强氧吸附活化；显著提升各基元反应的反应速率，从而在光催化反应中展现出优异的性能。