Ag/α-Fe2O3/g-C3N4光催化降解罗丹明B

Photocatalytic degradation of Rhodamine B by Ag/α-Fe2O3/g-C3N4 photocatalyst

为了使g-C3N4光生电子和空穴容易复合,改善可见光响应低等缺点,该实验中采用溶胶-凝胶法将g-C3N4和α-Fe2O3进行复合形成g-C3N4异质结光催化剂,再采用光沉积法将Ag沉积在α-Fe2O3/g-C3N4上,构建Z型机制Ag/α-Fe2O3/g-C3N4催化剂材料,改善光生电荷的分离和传输能力及可见光响应,进一步增强其光催化降解污染物活性.最后通过XRD、FT-IR、XPS、SEM、TEM、紫外-可见漫反射光谱表征光催化剂结构和性能,并以染料罗丹明B溶液模拟废水,研究催化剂的降解动力学特性,通过活性基团捕获实验探究光催化机制.实验结果表明:(1)α-Fe2O3和g-C3N4复合形成异质结,当α-Fe2O3负载量为3%时,α-Fe2O3/g-C3N4光催化性能比纯的g-C3N4有了明显的提高,光催化性能降解罗丹明B达到79%.(2)Ag负载在α-Fe2O3/g-C3N4,当Ag的负载量为3%时,在可见光下3.5h能够对罗丹明B达到95%以上的降解.(3)Ag/α-Fe2O3/g-C3N4增强的光催化剂性归因于α-Fe2O3和g-C3N4形成异质结以及Ag加入后形成Z型异质结结构.

In order to improve the recombination of photo-generated electrons and holes in g-C3N4 and the low visible light response,g-C3N4 andα-Fe2O3 were combined by sol-gel method to form g-C3N4 heterojunction photocatalyst.Then,the deposition of Ag was carried out by photodeposition at theα-Fe2O3/g-C3N4,a Z-type mechanism of Ag/α-Fe2O3/g-C3N4 catalyst was constructed to improve the separation and transport ability of photogenerated charge and visible light response,and further enhance its photocatalytic degradation activity for pollutants.The structure and properties of Ag/α-Fe2O3/g-C3N4 were characterized by XRD,FT-IR,XPS,SEM,TEM and UV-Vis diffuse reflectance spectroscopy.The wastewater was simulated using Rhodamine B solution to study the degradation kinetics of the catalyst.The photocatalytic mechanism was explored by active group capture experiments.The experimental results showed that:(1)α-Fe2O3 and g-C3N4 combine to form a heterojunction.When the loading ofα-Fe2O3 was 3%,the photocatalytic performance ofα-Fe2O3/g-C3N4 was obviously better than that of pure g-C3N4.With the increase of photocatalytic performance,the degradation of rhodamine reached 79%.(2)When the loading of Ag was 3%,more than 95%of Rhodamine could be degraded under visible light for 3.5 h.(3)The enhanced photocatalytic properties of Ag/α-Fe2O3/g-C3N4 were attributed to the formation of heterojunctions betweenα-Fe2O3 and g-C3N4 and Z-type heterojunction structures after Ag addition.