金属有机框架衍生的Co_(3)O_(4)/SnO_(2)复合材料制备及其光催化性能

Preparation and photocatalytic performance of Co_(3)O_(4)/SnO_(2) derived from a metal-organic framework

金属有机框架(metal-organic framework,MOF)材料ZIF-67衍生Co_(3)O_(4)十二面体纳米块在室温下与SnO_(2)复合,制备出立方体Co_(3)O_(4)/SnO_(2)复合光催化剂.煅烧后形成的Co_(3)O_(4)/SnO_(2)材料禁带宽度明显降低,荧光淬灭明显,说明Co_(3)O_(4)的加入拓展了SnO_(2)的光响应范围至可见光甚至红外光区域,同时促进了光催化反应过程中光生载流子的分离.以罗丹明B(Rhodamine B,Rh B)为目标反应物,在可见光下考察了MOF衍生的Co_(3)O_(4)/SnO_(2)的光催化降解活性,发现Co_(3)O_(4)/SnO_(2)在60 min内可以降解89.6%的Rh B,分别是纯SnO_(2)和纯ZIF-67的4.5倍和3倍.同时,Co_(3)O_(4)/SnO_(2)表现出了良好的光反应能力和稳定性.基于以上实验结果并结合自由基淬灭实验,提出了MOF衍生的Co_(3)O_(4)/SnO_(2)复合材料光催化降解有机染料RhB的机理.

A cubic Co_(3)O_(4)/SnO_(2) composite photocatalyst was prepared by combining dodecahedral nano-blocks derived from metal-organic framework(MOF)material ZIF-67 with SnO_(2) at room temperature.Results showed that the band gap of the calcined Co_(3)O_(4)/SnO_(2) material was significantly reduced,and the phenomenon of fluorescence quenching was obvious.The addition of Co_(3)O_(4)expanded the photoresponse range of SnO_(2) to visible light or even infrared light and simultaneously promoted the separation of photo-generated carriers during the photocatalytic reaction.With Rhodamine B(Rh B)used as the target reactant,the photocatalytic degradation activity of Co_(3)O_(4)/SnO_(2) derived from the MOF was investigated under visible light.It was found that Co_(3)O_(4)/SnO_(2) could degrade 89.6% Rh B within 60 min,which was 4.5 and 3 times greater than those of pure SnO_(2) and pure ZIF-67,respectively.In addition,Co_(3)O_(4)/SnO_(2) showed good photoreactivity and stability.Based on these experimental results and those from free-radical quenching experiments,the mechanism of photocatalytic degradation of organic dyes Rh B by the MOF-derived Co_(3)O_(4)/SnO_(2) composite material was proposed.