铋系复合光催化剂的制备及其对双酚A光催化降解研究

In-situ preparation of bismuth-based composite with enhanced photocatalytic activity for bisphenol A

将氧化铋(Bi_2O_3)与三聚氰胺或盐酸胍混合煅烧,通过原位晶相合成法制备了界面紧密接触的碳三氮四复合碳酸氧铋(g-C_3N_4/Bi_2O_2CO_3)和碳三氮四复合氯氧化铋(g-C_3N_4/BiOCl)复合光催化剂。采用X射线衍射仪、扫描电子显微镜、紫外-可见漫反射光谱仪等分析手段对复合光催化剂的结构和性能进行了分析表征。结果表明:Bi_2O_2CO_3和BiOCl纳米片均是从g-C_3N_4体相中生长出来,从而导致铋系氧化物和g-C_3N_4界面间的紧密接触。紫外-可见漫反射光谱分析结果表明,g-C_3N_4/Bi_2O_2CO_3和g-C_3N_4/BiOCl复合光催化剂的可见光吸收能力均优于g-C_3N_4和Bi_2O_3。在可见光照射下,复合光催化剂对双酚A表现出优越的降解性能。此外,探讨了复合光催化剂的光催化机理。由于g-C_3N_4和Bi_2O_2CO_3或BiOCl界面间的紧密接触导致了光生载流子的有效分离,从而提高了复合光催化剂的光催化活性。

The g-C3N4/Bi2O2CO3 and g-C3N4/BiOCl nanocomposites with intimately contacted interfaces were synthesized used in-situ crystal synthesis by mixing Bi2O3 nanoparticles with melamine or guanidine hydrochloride.The fabricated nanocomposites were well-characterized by various analytical techniques.The results showed that Bi2O2CO3 and BiOCl nanosheets growed out from the g-C3N4 bulk,producing closely contacted interfaces between Bi oxide component and g-C3N4 component.UV-Vis diffuse reflectance spectra of g-C3N4/Bi2O2CO3 and g-C3N4/BiOCl nanocomposites exhibited increased visible light absorption compared to g-C3N4 and Bi2O3 separately.Moreover,the nanocomposites showed significantly enhanced photocatalytic activity for the degradation of dibutyl phthalate and methyl orange under visible light.Moreover,aproposed photocatalytic mechanism for the enhanced photoactivity of nanocomposites was investigated.The increased photocatalytic activity was mainly attributed to the effective separation and transfer of photo-induced carriers in the intimate contact between g-C3N4 and Bi2O2CO3 or BiOCl.The results showed that the different precursors of g-C3N4 had a significant effect on the composite’s structure,i.e.,Bi2O3 can react to form different bismuth-based oxides depending on the different precursors used to generate g-C3N4.This work demonstrated a convenient way to fabricate visible light responsive materials with potential for environmental remediation.