石墨烯和氮化碳改性CuMn_(2)O_(4)催化臭氧氧化效能的对比

Comparison of the performance of catalytic ozonation by CuMn_(2)O_(4)modified by graphene and carbon nitride

为了开发新型功能材料,使用石墨烯(rGO)和石墨相C_(3)N_(4)(g-C_(3)N_(4))对CuMn_(2)O_(4)进行改性。采用X射线衍射仪、比表面积分析仪、X射线光电子能谱仪和电化学工作站等对改性前后的CuMn_(2)O_(4)进行了表征;比较了改性前后CuMn_(2)O_(4)对二苯甲酮-4(BP-4)的降解效果以及对溴酸盐的抑制效果;分析了2种复合催化剂的结构与性能之间的关系。结果表明:2种复合催化剂的比表面积、总孔容积和平均孔半径均有所增加;与CuMn_(2)O_(4)相比,CuMn_(2)O_(4)/rGO的比表面积增大了17.68倍,CuMn_(2)O_(4)/g-C_(3)N_(4)的比表面积增大了5.09倍;rGO和g-C_(3)N_(4)的改性不仅增加了催化剂的氧空位,而且增加了催化剂的阻值;与CuMn_(2)O_(4)相比,CuMn_(2)O_(4)/rGO中氧空位(OV)的相对含量增加了2.51倍,CuMn_(2)O_(4)/g-C_(3)N_(4)中OV的相对含量增加了2.74倍,且CuMn_(2)O_(4)/rGO的阻抗增大了18.70%,CuMn_(2)O_(4)/g-C_(3)N_(4)的阻抗增大了46.93%;rGO和g-C_(3)N_(4)改性后的催化剂均能进一步加快BP-4的降解,与CuMn_(2)O_(4)相比,CuMn_(2)O_(4)/rGO催化臭氧降解BP-4的速率提高了5.98倍,CuMn_(2)O_(4)/g-C_(3)N_(4)催化臭氧降解BP-4的速率提高了5.37倍。但是,二者对于溴酸盐生成量的抑制效果存在显著差异,与CuMn_(2)O_(4)相比,CuMn_(2)O_(4)/rGO催化臭氧能使HCO_(3)^(-)的生成量减少100%,而CuMn_(2)O_(4)/g-C_(3)N_(4)催化臭氧对HCO_(3)^(-)生成量的抑制效果没有提升。因此,CuMn_(2)O_(4)/rGO更适用于催化臭氧氧化过程。以上研究结果可以为多相催化臭氧氧化过程筛选新型高效催化剂提供参考。

In order to develop novel functional materials,CuMn_(2)O_(4)was modified by graphite C_(3)N_(4)(g-C_(3)N_(4))and graphene(rGO).The modified and unmodified CuMn_(2)O_(4)was characterized by XRD,specific surface area measurement,XPS and impedance test.The degradation efficiency of BP-4 and the elimination efficiency of HCO_(3)^(-) were compared.And the relationship between the structure and performance of CuMn_(2)O_(4)before and after modification was explored.The results showed that BET specific surface area,total pore volume and average pore radius of the two composite catalysts increased.Compared with CuMn_(2)O_(4),the specific surface area of CuMn_(2)O_(4)/rGO and CuMn_(2)O_(4)/g-C_(3)N_(4)increased by 17.68 and 5.09 times,respectively.The modification of rGO and g-C_(3)N_(4)not only increased the oxygen vacancy,but also increased the resistance of the catalyst.Compared with CuMn_(2)O_(4),the relative content of OV in CuMn_(2)O_(4)/rGO and CuMn_(2)O_(4)/g-C_(3)N_(4)increased by 2.51 times and 2.74 times,respectively.The resistance of CuMn_(2)O_(4)/rGO and CuMn_(2)O_(4)/g-C_(3)N_(4)increased by 18.70%and 46.93%,respectively.Compared with CuMn_(2)O_(4),the degradation rate of BP-4 by CuMn_(2)O_(4)/rGO increased by 5.98 times and the bromate formation yield decreased by 100%.The degradation rate of BP-4 by CuMn_(2)O_(4)/g-C_(3)N_(4)increased by 5.37 times,and the bromate formation yield couldn’t be reduced further.Thus CuMn_(2)O_(4)/rGO was more suitable for the catalytic ozonation.The above research could provide a guidance for the selection of novel and efficient catalysts in the process of heterogeneous catalytic ozonation.