钒酸铋晶面Z-型光催化材料可控制备与光解水制氢活性增强机理

The hydrogen energy development is of strategic importance to the sustainable development of human society. The project aims at the key scientific problems of low visible light absorption and high electron-hole recombination rate of the existing photocatalysts, and for the purpose of preparing high-efficiency visible light photocatalytic splitting water to produce hydrogen.The BiVO4 crystal is selected as a carrier, first loading Ag and C-doping g-C3N4-C quantum dots on the {010} facet, and then loading RuO2 on the {110} facet, to construct facet Z-type visible light fully splitting water to produce hydrogen catalyst g-C3N4-C / Ag {010} / RuO2 {110} / BiVO4.The crystal facet potential and Z-type heterojunction and oxidant RuO2 are used synergistically to enhance photoionization electron-hole separation transfer efficiency. The project will use crystal facet-engineering and Energy band theory as a guide to study the preparation of g-C3N4-C quantum dots and visible light absorption mechanism，and study the BiVO4 crystal facet structure precise control and precise load process and the facet Z-type photocatalyst controllable preparation. Exploring the facet and Z-type heterojunction composite drive and RuO2 synergistically enhance the photo-generated electron-hole separation and transfer law, Looking for the relationship between the photocatalytic activity and the facet loading quantum of the g-C3N4-C, Ag and RuO2,and reveal the mechanism of photocatalytic water splitting into hydrogen. The theory of the crystal facet and Z-type heterojunction composite driving photocatalytic reaction will be established, which provides guidance for the efficient and large-scale use of solar light photocatalytic water splitting into hydrogen.

发展氢能对实现人类社会可持续发展具有战略意义。项目针对光解水制氢存在可见光吸收效率低、电子-空穴复合率高等关键科学问题，选择BiVO4晶体为载体，应用晶面选择性沉积工艺，在{010}和{110}晶面上可控制备Z-型光催化剂g-C3N4-C/Ag{010}RuO2{110}/BiVO4。利用晶面和Z-型异质结协同提升光生电荷分离转移效率。项目拟采用原位合成方法制备C掺杂g-C3N4-C量子点并阐明量子尺寸效应增强光吸收机理；应用晶面工程和化学反应动力学理论对BiVO4晶面进行精确调控与精准负载，掌握利用化学反应沉积手段调控纳米粒子在晶面上的粒径和分布技术，实现晶面Z-型光催化剂可控制备；通过能带理论计算并结合实验查明晶面效应对光生电荷分离转移效率的影响，弄清纳米粒子氧化还原助剂负载量与光催化活性之间的关系，揭示有机污染物降解途径与光解水制氢机理。为高效大规模利用太阳能光解水制氢提供指导。

项目以g-C3N4和BiVO4掺杂改性及复合Z-型光催化剂的制备、光催化制氢及有机污染物降解为内容展开研究。通过能带理论计算并结合实验查明晶面（界面）缺陷结构及Z-型异质结协同效应对光生电荷分离转移效率的影响，阐明掺杂与缺陷结构调控光催化反应动力学规律，揭示Z-型光催化剂光解水制氢与降解有机污染物机理。取得的重要结果如下：. 项目设计制备出多种掺杂与缺陷结构g-C3N4纳米薄片，掌握了掺杂与缺陷结构精准调控g-C3N4催化性能工艺技术。研究发现，应用掺杂和缺陷多孔结构的协同效应，增多了其反应位点，拓宽了光响应范围，加快了光生载流子的分离与转移效率，样品产氢效率高达63.8mmolg-1h-1。设计制备出的2D/2D S-型TpPa-1-COF/g-C3N4光催化剂，借助异质结内建电场驱动显著提高了光催化剂的活性与稳定性。. 制备出介孔纳米纤维BiVO4-Ni/AgVO3、Co-BiVO4/Bi2O3 Z-型异质结光催化剂，通过晶格掺杂与异质结内建电场有效地提高了BiVO4对可见光的吸收性能，抑制了光生载流子的复合；同时掺杂形成的杂质能级和Z-型异质结内建电场提高了光生载流子的分离效率，获得了高效光催化性能。研究合成了晶面复合Cu/BiVO4/g-C3N4、g-C3N4/Ce-BiVO4光催化剂等，分析表明Cu纳米颗粒的局域表面等离子体效应，与晶面异质结协同效应进一步加速了电子的传导速率和氧化还原能力。该材料在降解有机污染物应用中表现出优异的性能。. 通过简单的水热法结合大气环境退火处理合成了三维分层多孔NiO-X/NF电极，这种电极具有从废水中去除Cr(VI)与同时产氢性能。在20 min时间Cr(VI)去除率达99.5%，产氢速率为1.1 mmolg-1h-1。该技术有望为电凝去除工业废水中的重金属离子提供新的思路。通过水热法与煅烧处理制备出C@TiO2空心球催化剂，可实现界面载流子管理，提高可见光催化性能。这种心壳异质结构光热催化剂的概念为大规模环境和能源应用提供了一种很有前途的策略。