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采用直流电压法将P25型TiO2粉末负载于FTO导电玻璃制成半导体矿物电极,研究其在不同小分子有机物(甲酸、甲醇、乙酸、乙醇)、不同浓度(0、20、40、60、80、100mmol/L)甲酸作为空穴捕获剂下对U(Ⅵ)的光催化还原。研究结果表明,由于电离能力的强弱不同,酸类小分子有机物对空穴的捕获能力强于醇类小分子有机物,添加的小分子有机物均能提高U(Ⅵ)的还原率且甲酸效果最好,添加60mmol甲酸光催化反应4h后,U(Ⅵ)的还原率能达到90.26%。扫描电镜(SEM)及能谱(EDS)分析表明,反应后电极表面有大颗粒方块状U(Ⅳ)的矿物生成,占据反应活性位点。电化学阻抗分析显示,反应后电极传递电子的阻力增大,电子传输能力减弱,催化活性降低。
The P25 TiO2 powder was loaded on the FTO conductive glass to form semiconductor mineral electrode by DC voltage method. The effects of organic solvents (formic acid, methanol, acetic acid and ethanol), different concentrations (0, 20, 40, 60, 80, 100mmol / L) formic acid as a hole-trapping agent for the photocatalytic reduction of U (Ⅵ). The results showed that due to the different ionization ability, the capture ability of small organic acids to holes is stronger than that of small organic molecules. The addition of small organic molecules can increase the reduction rate of U (Ⅵ) Good, adding 60mmol formic acid photocatalytic reaction 4h, U (Ⅵ) reduction rate can reach 90.26%. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis showed that the electrode surface after the reaction of large particles of U (Ⅳ) minerals generated, occupy the reactive site. Electrochemical impedance spectroscopy showed that the resistance of the electrode after the reaction increased, the electron transport ability weakened and the catalytic activity decreased.