Z型光催化剂 CoFe _(2) O _(4)/g C_( 3)N _(4)降解盐酸四环素性能

Performance in degradation of tetracycline hydrochloride over Z-scheme photocatalyst CoFe_(2)O_(4)/g-C_(3)N_(4)

残留在水中的盐酸四环素(TCH)结构复杂、难以降解,光催化技术被证实是一种去除水中盐酸四环素的有效方法。石墨型氮化碳(gC_(3)N_(4))因稳定、无毒、低成本等优点被广泛用作光催化降解有机污染物的光催化剂。但gC_(3)N_(4)的光生电子空穴对容易复合。为了抑制光生电子空穴对的复合,通过水热法制备了Z型光催化剂CoFe_(2)O_(4)/gC_(3)N_(4),用于可见光下降解盐酸四环素,并对光催化活性提高的原因和光腐蚀性能进行了分析。结果表明,当CoFe_(2)O_(4)复合量(质量分数)为25%时,CoFe_(2)O_(4)/gC_(3)N_(4)的光催化活性最佳,240 min后,盐酸四环素的降解率达到49.2%。CoFe_(2)O_(4)/gC_(3)N_(4)的光催化性能增强得益于可见光吸收量的增加和Z型电荷转移机制的协同作用。降解过程分为快速段和慢速段,均满足拟一级动力学方程。CoFe_(2)O_(4)/gC_(3)N_(4)具有较好的稳定性,循环后降解率的轻微损失是由于CoFe_(2)O_(4)的光腐蚀导致。该工作为双Z方案光催化剂的设计和光腐蚀的研究提供参考。

Tetracycline hydrochloride(TCH)in water is difficult to be degraded due to the complex structure.Photocatalytic technology has been proved to be an effective method for removing tetracycline hydrochloride from water.Graphite carbon nitride(g-C_(3)N_(4))is widely used as a photocatalyst for the photocatalytic degradation of organic pollutants due to its advantages of stability,non-toxic and low cost.However,the photogenerated electron hole pairs of g-C_(3)N_(4)are easy to recombine.In order to reduce the recombination of electron hole pairs,Z-scheme photocatalyst CoFe_(2)O_(4)/g-C_(3)N_(4)was prepared by hydrothermal method and used for tetracycline hydrochloride degradation under visible light.The reasons for the increase in photocatalytic activity and the photocatalytic corrosion performance were analyzed.Results showed that the photocatalytic activity of CoFe_(2)O_(4)/g-C_(3)N_(4)reached the highest and the degradation rate of tetracycline hydrochloride reached 49.2%after 240 minutes when the mass fraction of CoFe_(2)O_(4)was 25%.The enhanced photocatalytic performance of CoFe_(2)O_(4)/g-C_(3)N_(4)benefited from the synergistic effect of the increase of visible light absorption and Z-scheme charge transfer mechanism.The degradation process was divided into the fast stage and slow stage,all of which satisfied the pseudo-first-order kinetic equation.CoFe_(2)O_(4)/g-C_(3)N_(4)had good stability,and the slight loss of degradation rate after cycling was caused by the photocorrosion of CoFe_(2)O_(4).This work can provide a reference for the design of double Z-scheme photocatalysts and the investigation of photocorrosion.