二维微孔碳-纳米TiO_(2)/C_(3)N_(4)复合光催化剂用于增强吸附-光催化协同效应

Crafting 2D microporous carbon-TiO_(2)/C_(3)N_(4) hybrid structure for enhanced synergy of adsorption-photocatalysis

碳基复合型光催化剂能够有效克服传统TiO_(2)催化剂吸附能力差和可见光响应差的缺陷。设计并制备了二维微孔碳负载纳米TiO_(2)/C_(3)N_(4)三元复合型光催化剂,探究复合后催化剂物理结构和光电学性质的改进,并用于可见光催化降解对二甲苯和罗丹明B,降解率分别达96.5%和92.2%,其反应速率常数约为工业TiO_(2)催化剂(P25)的7.8倍。该三元复合型催化剂的吸附-光催化协同性能显著增强,归因于类石墨烯结构的微孔碳与光活性纳米粒子的界面效应,促进了反应过程中的光电子传导和污染物富集,同时扩展了材料的光响应范围;引入纳米级氮化碳(C_(3)N_(4))进一步与TiO_(2)在碳片层上结合形成二元半导体结构,能够加速光生电子与空穴的分离,提高整体材料的光催化活性。

Carbon-based photocatalyst can effectively avoid the defects of traditional TiO_(2) catalysts,such as poor adsorption capacity and wide band gap.A 2D microporous carbon supported nano-TiO_(2)/C_(3)N_(4) ternary composite was designed as the visible-light induced photocatalyst,and the improvement of the physical structure and photoelectric property of the composite catalyst was investigated.Photocatalytic degradation of paraxylene and rhodamine B was simulated,and the degradation efficiency reached 96.5%and 92.2%respectively,with the primary kinetic constant 7.8 times as that of commercial TiO_(2) catalyst(P25).The results showed that the synergy effect for adsorption-photocatalysis of the composite catalyst was significantly enhanced,which was mainly attributed to(1)the interface effect between the graphene-like microporous carbon and the photo-active nanoparticles,which promoted the photoelectron transfer and the enrichment of pollutants during the reaction process,as well as expanding the light response range of the composite,(2)formation of binary compound semiconductor by combining nano-C_(3)N_(4) and nano-TiO_(2),which accelerated separation of photogenerated electron from the hole,and further improved photocatalytic activity of the composite catalyst.