Ag/g-C_(3)N_(4)复合光催化剂的制备及其光解水产氢性能研究

Preparation of Ag/g-C_(3)N_(4)composite photocatalyst and its photocatalytic hydrogen production performance

通过光沉积法制备了银含量不同的银/石墨相氮化碳(Ag/g-C_(3)N_(4))复合光催化剂。通过扫描电子显微镜、X射线衍射仪、X射线光电子能谱仪、紫外-可见漫反射光谱仪等对其表面形貌、结构、化学组成及光学性能进行了表征和测试。结果表明:Ag/g-C_(3)N_(4)复合光催化剂主要由不规则的大块颗粒和许多大小、形状不一的小颗粒组成;Ag纳米颗粒的引入没有改变g-C_(3)N_(4)的晶体结构,Ag纳米颗粒以零价金属形式存在;Ag/g-C_(3)N_(4)复合光催化剂紫外区光吸收性能显著提高;Ag纳米颗粒的引入有效地抑制了光生电子-空穴对的复合,同时也促进了电荷的迁移。光解水产氢实验表明,Ag含量不同的Ag/g-C_(3)N_(4)复合光催化剂的产氢速率相比于g-C_(3)N_(4)都明显提升,且1%Ag/g-C_(3)N_(4)的产氢速率最高,达到了636.71μmol/(g·h),是g-C_(3)N_(4)产氢速率的8.9倍。

Silver/graphitic phase carbon nitride(Ag/g-C_(3)N_(4))composite photocatalysts with different silver contents were prepared by photo-deposition.Their surface morphologies,structures,chemical compositions,and optical properties were characterized and tested by scanning electron microscopy,X-ray diffractometry,X-ray photoelectron spectrometry,and UV-Vis diffuse reflectance spectroscopy.The results showed that the Ag/g-C_(3)N_(4)composite photocatalysts were mainly composed of irregular bulk particles and many small particles with different sizes and shapes.The crystal structure of g-C_(3)N_(4)was not changed by the introduction of Ag nanoparticles,which existed in the form of zero-valent metal.The UV absorption properties of Ag/g-C_(3)N_(4)composite photocatalysts were improved remarkably.the introduction of Ag nanoparticles effectively suppressed the recombination of photogenerated electron-hole pairs,and promoted the charge migration.The photocatalytic hydrogen production experiments showed that the hydrogen production rates of the Ag/g-C_(3)N_(4)composite photocatalysts with different Ag contents were significantly improved compared with that of g-C_(3)N_(4),and the hydrogen production rate of 1%Ag/g-C_(3)N_(4)was the best,reaching 636.71μmol/(g·h),which was 8.9 times that of g-C_(3)N_(4).