Mechanism and photocatalytic hydrogen production performance of Ag2CrO4/g-C3N4 composites
A series of Ag2CrO4/g-C3N4 composites with photocatalytic hydrogen(H2)production were prepared by in-situ chemical deposition method.The phase composition,functional group structure,microscopic mor-phology,elemental compositions and their species of the composites were characterized using X-ray diffraction,Fourier transform infrared,field emission scanning electron microscope,transmission electron microscope and X-ray photoelectron spectroscopy.The light absorption properties and photogenerated carrier separation of the samples were investigated by UV-visible diffuse reflectance spectra,photoluminescence spectroscopy and photo-current testing.The H2 production performance of the photocatalysts and the influencing factors were investiga-ted experimentally.The results showed that the introduction of Ag2CrO4 did not change the originally heterocy-clic structure of g-C3N4,and nanostructure Ag2CrO4 was dispersed on the surface of g-C3N4.Although Ag2CrO4 had no H2 production effect,the H2 production rate of the composite increased first and then decreased with the increase of Ag2CrO4 content.The H2 production rate of the optimal photocatalyst Ag2CrO4/C3N4-4％was 2.7 times that of pure g-C3N4.The reason was mainly attributed to the appearance of Z-type heterojunction between of Ag2CrO4 and g-C3N4,which broadened the visible light response range of g-C3N4,reduced the charge transfer impedance,and promoted the separation and migration of photogenerated carriers.
carbon nitridesilver chromateheterojunctionphotocatalysthydrogen production
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