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通过高温液相生长法在氧化铟锡玻璃上构筑了g-C_3N_4薄膜电极,该电极作为阳极在H_2O_2辅助作用下光电催化降解亚甲基蓝.研究结果表明,g-C_3N_4与H_2O_2在可见光下存在协同作用;在外加电压1.5 V,50 mmol L-1H_2O_2条件下,亚甲基蓝的降解率在2 h内由35.92%提高至53.43%.系统研究了H_2O_2浓度、外加电压、初始p H对亚甲基蓝降解的影响.采用电子顺磁共振自旋捕捉技术和自由基猝灭实验等方法证实了·O2-和·OH为光电催化过程中的主要氧化物种,提出了可能的催化反应机理,在外加H_2O_2条件下,g-C_3N_4受可见光激发生成的光生电子被O2或H_2O_2捕获,最终生成·OH,从而将有机染料降解.g-C_3N_4薄膜电极表现出较高的稳定性.
The g-C_3N_4 thin film electrode was fabricated on indium tin oxide glass by high temperature liquid phase growth method, and the electrode was used as an anode to photocatalytically degrade methylene blue with the help of H_2O_2.The results showed that g-C_3N_4 and H_2O_2 had synergistic effect in visible light, The degradation rate of methylene blue increased from 35.92% to 53.43% within 2 h under the voltage of 1.5 V and 50 mmol L-1H_2O_2. The effects of H 2 O 2 concentration, applied voltage and initial p H on the degradation of methylene blue were studied systematically. The results showed that · O2- and · OH were the main oxide species in the photoelectrocatalysis process, and the possible catalytic reaction mechanism was proposed. Under the condition of H 2 O 2 addition, g-C 3 N 4 The photoelectrons generated by visible light were captured by O2 or H_2O_2 to finally form · OH, which degraded the organic dye. The G-C_3N_4 thin film electrode showed high stability.