Photocatalytic Hydrogen Production Properties and Mechanism Analysis of TiO2@H+/g-C3N4 Composites
The influence of the loading amount of TiO2 on the photocatalytic H2 production performance of TiO2@H+/g-C3N4 composites were studied.Graphite phase carbon nitride(g-C3N4)was first treated with sulfuric acid to obtain pickled carbon nitride(H+/g-C3N4),and then TiO2@H+/g-C3N4 composites were prepared by loading TiO2 on the surface of H+/g-C3N4 by calcination method.The photocatalytic hydrogen production of TiO2@H+/g-C3N4 composite was characterized by transmission electron micros-copy,X-ray diffractometer,UV-vis diffractometer and specific surface analyzer.The photocatalytic perfor-mances of H2 production of TiO2@H+/g-C3N4 composites were investigated under the irradiation of visible light.The photocatalytic hydrogen production mechanism of TiO2@H+/g-C3N4 composite was discussed.The results show that the TiO2@H+/g-C3N4 composites are synthesized by calcination.The photocatalytic property of H+/g-C3N4 is increased by the loading of TiO2,which is due to the separation promotion of the photogenerated electron-hole pairs and the acceleration of the electrons transfer rate by TiO2/g-C3N4 heterojunctions.Moreover,the loading amount of TiO2 has great effects on the photocatalytic H2 produc-tion performance of TiO2@H+/g-C3N4 composites.With TiO2 loading of 25%,the photocatalytic H2 pro-duction rate of the prepared 25-TiO2@H+/g-C3N4 composite is the highest,which is 3.47 mmol·g-1·h-1 and about 4.05 times of that of H+/g-C3N4.This good property is attributed to the large specific surface area and high absorbance of 25-TiO2@H+/g-C3N4 composite.Moreover,the prepared 25-TiO2@H+/g-C3N4 composites show good stability in the process of photocatalytic H2 production.
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