钽酸盐纳米材料的制备及光催化性能研究

发布时间：2018-06-03 17:48

  本文选题：钽酸盐 + 光催化　； 参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：人类社会面临着能源和环境问题,光催化材料可以有效的利用太阳能,既可以裂解水制取氢气,也可以应用在环境治理中,可以有效的降解水体中的有机污染物,这种环保无污染的技术,有希望解决未来的能源问题以及环境污染问题。迄今为止所研究的光催化剂中,钙钛矿型光催化剂以它特有的结构在光催化领域具有较大的应用前景,钙钛矿型钽酸盐材料显示了好的光分解水制氢性能,本文采用熔盐法制备了NaTaO_3纳米催化剂,探讨了热处理温度、升温速率、保温时间和Nb的掺杂对NaTaO_3物相、形貌和性能的影响,并研究了Sr的掺杂以及NiO的复合对NaNb_(0.5)Ta_(0.5)O_3物相、形貌、催化性能和电化学的影响。研究结果表明,热处理温度为750℃,升温速率为5 ℃/min,保温时间为2h,在这个制备条件下,可以得到结晶良好,微观相貌为20-50 nm的NaTaO_3立方形貌。NaTaO_3具有较高的光催化活性,产氢速率最高分别为0.57 mmol/h/g。通过选用Nb元素对NaTaO_3B位掺杂,选用Sr元素对NaNb_(0.5)Ta_(0.5)O_3 A位掺杂,通过NiO的负载在NaNb_(0.5)Ta_(0.5)O_3立方体表面分别合成NaNbxTa_(1-x)O_3,Sr_xNa_(1-2x)Nb_(0.5)Ta_(0.5)O_3,NiO/NaNb_(0.5)Ta_(0.5)O_3光催化剂。通过光催化制氢性能、光催化降解污染物性能和电化学性能研究表明,Nb元素进入晶体结构中,获得了优化后的Nb~(5+)掺杂量为0.5,NaNb_(0.5)Ta_(0.5)O 36 h制备氢气为14.59 mmol/g,产生的氢气总量是NaTaO_3的3.8倍,在光照40 min后降解96%的罗丹明B,50 min后完全降解,降解效率最高。优化得到了Sr~(2+)掺杂量为3%,Sr_xNa_(1-2x)Nb_(0.5)Ta_(0.5)O_3样品的制氢量最高为18.56 mmol/g,制氢速率为3.09 mmol/h/g。通过NiO的负载在NaNb_(0.5)Ta_(0.5)O_3立方体表面,NiO/NaNb_(0.5)Ta_(0.5)O_3的吸收边发生了红移,扩宽了光催化剂的光响应范围。获得了优化后的NiO的负载量为3%,3%NiO/NaNb_(0.5)Ta_(0.5)O_3样品的6 h制氢量为26.70 mmol/g,稳定后的制氢速率为4.45 mmol/h/g,同样是是NaNb_(0.5)Ta_(0.5)O_3的1.83倍。
[Abstract]:Human society is faced with energy and environmental problems, photocatalytic materials can effectively use solar energy, not only can split water to produce hydrogen, but also can be used in environmental control, can effectively degrade organic pollutants in water. This environmentally-friendly and non-polluting technology promises to solve future energy and environmental pollution problems. So far, perovskite photocatalyst has a great application prospect in the field of photocatalysis because of its unique structure. Perovskite tantalate materials show good performance of photodecomposition of water to produce hydrogen. In this paper, NaTaO_3 nanocatalysts were prepared by molten salt method. The effects of heat treatment temperature, heating rate, holding time and NB doping on the phase, morphology and properties of NaTaO_3 were investigated. The phase and morphology of NaNb_(0.5)Ta_(0.5)O_3 were also studied by Sr doping and NiO composite. Effects of catalysis and electrochemistry. The results show that the NaTaO_3 cubic morphology. NaTaOs _ 3 with a microstructure of 20-50 nm has high photocatalytic activity under the condition that the heat treatment temperature is 750 鈩，

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