Gomis-Berenguer Alicia, Eliani Irma, F Lourenço Vânia, J Carmona Rocio, F Velasco Leticia, O Ania Conchi
POR2E group, CEMHTI, CNRS (UPR 3079), Université d'Orléans, 45071 Orléans, France.
Instituto Nacional del Carbón (INCAR-CSIC), Apdo. 73, 33080 Oviedo, Spain.
Materials (Basel). 2019 Jan 26;12(3):385. doi: 10.3390/ma12030385.
We have explored the impact of the incorporation of various amounts of carbons from varied physicochemical features as additives to Bi₂WO₆ for the photocatalytic degradation of a dye using simulated solar light. Data has revealed that the composition and acidic character of the carbon additive are important parameters in the performance of the Bi₂WO₆/carbon catalysts. The presence of a carbon additive improved the conversion of the dye, evidencing the occurrence of charge transfer reactions that involve radical mediated reactions. The catalysts prepared with 2 and 5 wt.% of carbon additive outperformed the bare semiconductor, despite the shielding effect of the carbon matrix. The acidic nature of the Bi₂WO₆/carbon catalysts governs the degradation pathway (due to the preferential adsorption of the dye), that proceeds via the deethylation of the auxochrome groups of the dye at short irradiation times, followed by the cleavage of the chromophore at long irradiation times. Regarding the characteristics of the carbons, the photocatalytic degradation rate is accelerated by carbons of acidic character and high oxygen content, whereas the porosity seems to play a minor role. The presence of the carbon additives also affects the toxicity of the treated solutions, rendering lower values after shorter irradiation periods.
我们研究了将具有不同物理化学特性的各种碳含量作为添加剂掺入Bi₂WO₆中，利用模拟太阳光对染料进行光催化降解的影响。数据表明，碳添加剂的组成和酸性特征是Bi₂WO₆/碳催化剂性能的重要参数。碳添加剂的存在提高了染料的转化率，证明了涉及自由基介导反应的电荷转移反应的发生。尽管存在碳基质的屏蔽效应，但用2 wt.%和5 wt.%碳添加剂制备的催化剂性能优于裸半导体。Bi₂WO₆/碳催化剂的酸性性质决定了降解途径（由于染料的优先吸附），即在短辐照时间内通过染料助色基团的脱乙基作用进行，随后在长辐照时间内发色团发生裂解。关于碳的特性，酸性和高氧含量的碳会加速光催化降解速率，而孔隙率似乎起次要作用。碳添加剂的存在也会影响处理后溶液的毒性，在较短辐照时间后毒性值较低。
