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利用水热合成法制备了C_3N_4/BiOBr复合可见光催化剂,通过XRD、FT-IR、SEM、DRS、PL等手段对催化剂的物相组成和光化学性能进行了系统表征,利用对罗丹明B(RhB)的降解实验评价了催化剂在可见光照下的光催化降解活性和稳定性并通过ESR分析和自由基捕获实验探究了RhB的光催化降解机制.结果表明,水热合成法可成功制备结晶性能良好的C_3N_4/BiOBr复合可见光催化剂;C_3N_4的复合降低了BiOBr光催化剂的电子-空穴的复合,提高了光催化降解活性,其中15%C_3N_4/BiOBr的活性最佳,可见光照18 min后RhB的脱色率达100%,较纯BiOBr提高了1.5倍,且重复使用5次后仍具有较高的光催化降解活性;复合催化剂光催化降解RhB过程中参与降解的主要活性物种为空穴(h~+)和超氧自由基(·O_2~-),其中h~+影响更为显著.
The photocatalyst C_3N_4 / BiOBr was prepared by hydrothermal method. The phase composition and photochemical properties of the catalyst were systematically characterized by XRD, FT-IR, SEM, DRS and PL. The RhB (RhB) , The photocatalytic degradation activity and stability of the catalyst under visible light irradiation were evaluated and the photocatalytic degradation mechanism of RhB was investigated by ESR analysis and free radical trapping experiments.The results showed that the hydrothermal synthesis method could successfully prepare a C_3N_4 / BiOBr composite visible light photocatalyst; C_3N_4 composite reduced BiOBr photocatalyst electron-hole recombination, increased photocatalytic degradation activity, of which 15% C_3N_4 / BiOBr activity best visible light 18 min RhB decolorization rate Up to 100%, 1.5 times higher than that of pure BiOBr, and still had higher photocatalytic activity after repeated use for 5 times. The main active species involved in the degradation of RhB by photocatalytic degradation of composite catalyst was hole (h ~ +) And superoxide radical (· O_2 ~ -), of which h ~ + effect is more significant.