压电化学效应纳米棒制备及机械催化振动降解染料研究

Under illumination, photocatalyst materials create electrons and holes and further generate the strong oxidant free radicals which can degrade dye. Similarly, under vibration, piezoelectric materials can also create electrical charges and further generate the strong oxidant free radicals to degrade dye. The new effect is called “piezoelectrochemical effect”, which can be considered as the product of piezoelectric effect and electrochemical effect. The new catalytic technology is called “mechanocatalysis”. Investigation on the fabricating piezoelectric nanofibers and the application of piezoelectrochemical effect for the new catalytic technology—mechanocatalysis, is useful in the field of clean-energy and environmental protection, such as vibration-decomposing organic dyes in wastewater, vibration-charging chemical cell, vibration splitting water for hydrogen production. In this project, we plan to synthesize the typical 1-D piezoelectric ZnO, Na0.5Bi0.5TiO3 and BaTiO3; nano-fibers via a hydrothermal method and systematically study the piezoelectrochemical effect for the application in mechanocatalytically decomposing organic dyes wastewater under vibration. We also plan to investigate the dependence of the concentration of electrolyte solution, pH value and the addition of catalyst and optimize these parameters and conditions to obtain a high degradation ratio of >80%. The generation process of intermediate product-- strong oxidant free radicals will also studied to understand the physical mechanism of piezoelectrochemical coupling. Some piezoelectric nano-materials such as ZnO, often possess excellent photocatalytic properties. We also plan to combin photocatalysis with mechanocatalysis to realize high degradation ratio. The execution of this project can provide academic reference and scientific basis for the design of novel piezoelectrochemical effect and the preparation of novel mechanocatalyst.

光催化材料在光照下可产生电子和空穴，其在溶液中可产生强氧化的活性自由基，使染料降解。类似地，压电材料在振动下也可诱导出正负电荷，在溶液中产生活性自由基，使染料降解。这称为压电化学效应，其可看成压电和电化学效应的乘积。这种新的催化技术称为机械催化。开展压电化学效应压电纳米材料制备及对机械催化的研究，在振动降解染料、振动分解水制氢、振动式充电电池等环保和新能源领域有重要的科学意义。本课题拟采用水热法制备钛酸钡、钛酸铋钠等纳米棒（线）；对压电化学效应系统地研究；研究染料浓度、pH值、催化剂添加量等对机械催化振动降解有机染料的影响并优化相关参数，使降解率达 80%以上；研究中间产物--强氧化活性自由基的产生过程以探究压-电-化学耦合的物理机制；还将利用压电纳米棒本身良好的光催化性能，进行光催化和机械催化的联合以提高降解率。这些研究可为新型压电化学效应机械催化材料的制备和应用提供科学参考和依据。

光催化材料在光照下可产生电子和空穴，其在溶液中可进一步产生强氧化的活性自由基，使染料降解。类似地，压电材料在振动下可诱导出正负电荷，在溶液中产生活性自由基，使染料降解。这称为压电化学效应，其可看成压电和电化学效应的乘积。这种新的催化技术称为机械催化。本项目中，采用水热等方法制备了钛酸钡、氧化锌、铁酸铋等纳米棒（线）并表征了其压电化学效应；实验上发现，在振动下，这些材料对酸性橙7、罗丹明B等染料废水的机械催化降解率可达80%左右，其中钛酸钡纳米线以及铁酸铋纳米片对罗丹明B溶液的机械催化降解率均达95%以上。还获得了染料浓度、染料种类、压电催化剂添加量等对机械催化振动降解有机染料的影响规律；实验中，还进一步观测了催化过程中产生的强氧化活性自由基种类。探究了压-电-化学耦合的物理机制。利用压电纳米棒本身良好的光催化性能和热催化性能，还设计实现了机械催化和光催化协同双催化，以及机械催化与热催化协同催化降解染料废水，进一步提高了染料降解率。压电纳米材料机械催化效应在振动降解染料、振动分解水制氢、振动式充电电池等环保和新能源领域有重要的应用前景。