【作者】 刘伟；

【导师】 董世知；

【作者基本信息】 辽宁工程技术大学 ， 材料科学与工程， 2021， 硕士

【摘要】 微纳米材料的很多性能和特性是和其缺陷紧密联系在一起的。低维度下的微纳米非晶材料具有很大的比表面积和缺陷结构,不仅本身具有不错的催化性能,还能更好的为原子吸附提供吸附位点。本论文主要以氧化锆为研究目标,首先通过液相法制备了不同晶态（晶态、非晶态和不同比例晶态-非晶态混合态）的氧化锆纳米线,然后对不同晶态的氧化锆纳米线进行了相应的表征和研究,阐述了非晶氧化锆材料的缺陷特点以及如何利用其缺陷进行单原子构筑,进而达到催化二氧化碳还原和硝基苯加氢的目的。结果表明,非晶材料作为基底负载单原子的构筑,提供了一个有价值的全新的设计理念,实现了载体和金属单原子的共通优化。主要研究结论有以下几个方面:1.利用简单的超声辅助分离法,制备了氧化锆微纳米线的前驱体。通过精确控制热处理温度,得到了非晶态、晶态以及不同比例双相（非晶态-晶态）混合氧化锆纳米线。研究发现,非晶、晶态、非晶-晶态双相氧化锆纳米线也具有一定的光催化二氧化碳还原性能,非晶氧化锆的光催化还原二氧化碳的性能最好,其效率为12.86μmol g^-1h^-1,选择性高达96.5%,活性明显高出两相57.4%和95.1%以及晶体114%,突出了非晶在光催化二氧化碳还原上的优势;2.利用简单的化学控制法,在非晶氧化锆基底材料上,成功地负载了单原子Pt,再通过EPR等一系列的技术表征发现,非晶材料拥有丰富的氧空位和缺陷,能很好地解决单原子团聚和熟化的现象,保证了单原子催化剂在4次循环实验中还可以保持高效性,是负载单原子的理想基底材料,单原子又可以优化非晶氧化锆的性能,使其效率达到16.61μmol g^-1h^-1,选择性高达97.6%;3.比较不同Pt负载量的Pt/ZrO₂催化剂（Pt负载量分别为1.97%和6.10%）在气相条件下的光催化二氧化碳还原性能。PtNP/ZrO₂的光催化还原二氧化碳的效率只有1.87μmol g^-1h^-1,PtSA/ZrO₂高出其近一个数量级。还有PtSA/ZrO₂催化硝基苯加氢的转化率为97.1%,对苯胺的选择性为98.0%,明显比PtNP/ZrO₂高。结果显示,单原子催化剂在减少贵金属Pt用量的情况下,还展示出了优异的光催化二氧化碳还原性能和硝基苯催化加氢性能。该论文有图35幅,表4个,参考文献110篇。更多还原

【Abstract】 Many properties and characteristics of micro and nano materials are closely related to their defects structure.Micro and nano amorphous materials at low dimensions have large specific surface area and defect structure,which not only have good catalytic performance,but also provide active sites for atomic adsorption.This thesis mainly takes zirconium dioxide as the research target.Firstly,zirconium oxide nanowires with different crystal phases（crystalline phase,amorphous phase and different ratios of crystalline-amorphous mixed phase）are prepared,and then zirconium oxide nanowires with different crystal phases are prepared.The nanowires were characterized and studied accordingly,and the defect characteristics of amorphous zirconia materials and how to make use of the defect to construct a single atom to achieve the catalytic purpose of CO₂reduction and nitrobenzene hydrogenation are described The results show that the amorphous material as a base to support the construction of single atoms provides a valuable new design concept and realizes the optimization of metal single atoms.The main research conclusion are as follows:1.Using a simple ultrasonic-assisted separation method,the precursor of ZrO₂micro-nanowires was prepared.By precisely controlling the temperature of the heat treatment,mixed ZrO₂nanowires in amorphous,crystalline,and different ratios of two-phase（amorphous-crystalline）are obtained.Studies have found that amorphous,crystalline,and amorphous-crystalline biphasic ZrO₂a nanowires also have certain photocatalytic carbon dioxide reduction performance.ZrO₂（200℃）has the best performance for photocatalytic reduction of carbon dioxide,with an efficiency of 12.86μmol g^-1h^-1,the selectivity is as high as 96.5%,the activity was significantly higher than that of the two phases by 57.4%and 95.1%,as well as the crystal 114%,the advantage of amorphous in photocatalysis is highlighted;2.Using simple chemical control,on the amorphous zirconia basal material,load a single atom successfully Pt,characterized by a series of technology such as EPR again found that amorphous material is rich in oxygen vacancy and defects,can well solve the single atom reunion and the phenomenon of aging,guarantees the monatomic catalyst in the four cycle experiments can also keep the high efficiency,is the load of single atom.The ideal substrate material,single atom can optimize the performance of amorphous ZrO₂,so that the efficiency of16.61μmol g^-1h^-1,selectivity up to 97.6%;3.Comparing the photocatalytic carbon dioxide reduction performance of Pt/ZrO₂catalysts with different Pt loads（Pt loads were 1.97%and 6.10%respectively）in the gas phase,The photocatalytic reduction efficiency of PtNP/ZrO₂is only 1.87μmol g^-1h^-1,which is nearly one order of magnitude higher than that of PtSA/ZrO₂,and the catalytic conversion of PtSA/ZrO₂for nitrobenzene hydrogenation is 97.1%,and the selectivity for aniline is 98.0%,which is obviously higher than PtNP/ZrO₂.The results showed that single atom catalyst also shows excellent photocatalytic performance of carbon dioxide reduction and catalytic hydrogenation performance of nitrobenzene under the condition of reducing the amount of precious metal Pt.The paper has 35 pictures,4 tables,and 110 references.更多还原