【作者】 赵鹏；

【导师】 樊唯镏；

【作者基本信息】 山东大学 ， 无机化学， 2018， 硕士

【摘要】 伴随工业快速发展而来的能源危机与环境污染越来越受到人们的关注,成为目前人类亟待解决的重要问题。1972年Fujishima等人首次实现了金红石二氧化钛光电极的光电催化分解水制氢,随后相关研究者又发现粉体半导体材料光解水制氢技术。从而掀起了利用含量丰富的可再生太阳能制备绿色氢能源的研究热潮。无论是光电催化还是光催化过程,其核心问题都是对光催化剂材料的研究。近来,具有d10电子构型的半导体由于具有较好的载流子迁移效率表现了良好的光催化性能,因而受到广泛关注。本论文以d10电子构型的镓酸锌尖晶石作为主要研究对象,通过缺陷调控下的非金属元素掺杂及复合异质结构建方法,以实现对镓酸锌光催化剂电子结构的调控,增强其光催化产氢能力。主要研究内容及相关结论如下:第二章中以硼氢化钠作为硼源和脱氧剂,以氨气作为氮源,通过简单的一步煅烧法成功制备了氧空位调控下的B/N共掺镓酸锌纳米球。氧空位调控下的B/N共掺镓酸锌在没有沉积铂作为助催化剂条件下即表现了优异的光催化产氢效率,比同样条件下的氧空位调控B掺杂及N掺杂镓酸锌光催化剂性能更加优异,是未掺杂镓酸锌的三倍左右。这主要是由以下原因导致的:一方面,由于B-N键的形成,施主杂质与受主杂质间实现了有效的电荷补偿,促进了载流子分离;另一方面,掺杂过程中在镓酸锌材料表面形成有效的活性位点,加快了表面反应。载流子分离效率及表面反应效率的协同提高,促进了光催化产氢性能的增强。并且,通过实验表征与理论计算相结合对掺杂后镓酸锌光催化性能提升机制进行了解释。第三章中,以硫化钠为硫源,镓酸锌作为主体光催化剂(和锌源),于100℃的硫化钠水溶液中在镓酸锌薄片表面原位生长硫化锌,得到锌空位调控的硫化锌/镓酸锌复合异质结构。通过改变硫化钠溶液的浓度调控生成硫化锌相的含量。研究发现随着硫化锌相的增多,样品的光催化效率呈现先增强后减弱的变化规律,硫化钠溶液浓度为0.02 M时光催化产氢性能最高,达到1064 umol/g/h,是纯相镓酸锌的8倍多。这主要是由于镓酸锌/硫化锌界面形成异质结促进了载流子的分离;但是由于硫化锌中的锌来源于镓酸锌主体光催化剂,因此随着硫化锌相的增多,镓酸锌结构的破坏越严重,不利于载流子的分离和迁移,表现降低的光催化活性。所以,复合异质结材料的光催化产氢性能随着硫化锌相比例的增加,表现出先升高后降低的变化趋势。我们在第四章中系统总结了本论文的研究内容,归纳了该研究工作的创新点,并对下一步研究方向进行了展望。更多还原

【Abstract】 The energy crisis and environmental pollution,accompanying with the rapid development of industry,have received more and more attention and become an important issue that need to be resolved urgently.In 1972,Fujishima and Honda used the rutile titanium dioxide single crystal photoelectrode for photoelectrocatalyrtic water splitting for hydrogen evolution.Subsequently,scientists achieved photocatalytic hydrogen production from water splitting using power semiconductor materials.Since then,the research on the use of inexhaustible solar energy to produce green hydrogen energy has attracted more and more concern.Whatever for photoelectrocatalysis or photocatalysis,the key issue of study is semiconductor catalyst material.Recently,semiconductors with d10 electron configuration have attracted wide attention owing to their excellent carrier transfer efficiency and good photocatalytic performance.In this thesis,ZnGa2O4 with d10 electronic configuration act as the main photocatalyst materials for study.Non-metal elements doping and heterostructure construction with modification of defects were used to improve the photocatalytic activity of ZnGa204 photocatalyst.The main research content and related conclusions are as follows:In the second chapter,we present a facile method to prepare B/N-codoped ZnGa2O4 nanospheres accompanied with oxygen vacancy modification by using ammonia as nitrogen source and NaBH4 as boron source and reducing agent.The Vo-modified B/N-codoped ZnGa2O4(Vo-B/N-ZGO)exhibits excellent photocatalytic hydrogen production efficiency even without any additional cocatalyst,which is better than the Vo-modified B-doped ZnGa2O4(Vo-B-ZGO)or N-doped ZnGa2O4(N-ZGO)samples and as high as about three times that of undoped ZnGa2O4.This superior photocatalytic performance of Vo-B/N-ZGO could be explained based on the following reasons.For one,the synergetic effect of boron and nitrogen dopants with oxygen vacancies greatly broadens its light absorption range.For another,the Vo-modified B/N-codoping obviously enhances carrier separation and also produces rich reactive sites for proton reduction reaction.In addition,the theoretical calculation was combined with experimental characterization to explain the mechanism of ZnGa2O4 photocatalytic reaction.In the third chapter,we successfully prepared ZnS/ZnGa2O4 heterostructure through in-situ growth of ZnS in 100℃ aqueous solution with Na2S as S source and ZnGa2O4 as Zn source as well as photocatalyst substrate.The content of ZnS phase is controlled by changing the concentration of Na2S solution.It was found that the photocatalytic hydrogen production of photocatalyst first increased and then decreased with the increase of ZnS.When the concentration of Na2S solution was 0.02 M,the composite material manifest the best photocatalytic hydrogen evolution rate,up to 1064 umol/g/h,which is more than 8 times of ZnGa2O4.The heterojunction at the interface of ZnS/ZnGa2O4 photocatalyst promotes the separation of carriers and the dramatically enhanced photocatalytic activity.However,since the Zn atoms of ZnS are derived from ZnGa2O4 substrate,more Zn atoms will be lost and becoming recombinatio center with the increase of ZnS content,which is not conducive to photocatalytic activity.Therefore,the photocatalytic hydrogen production performance of composite heterojunction materials shows a trend of increasing first and then decreasing as the proportion of zinc sulfide increases.In the fourth chapter,the research work and related innovation point have been summarized and further research work has also been put forward.更多还原