| Nowadays, environmental pollution harms seriously human survival environment and people's health. Energy shortage has gradually become a major problem affecting the human survival and social development. The conversion of solar energy, which is inexhaustible, into hydrogen using semiconductor photocatalysis is one of effective methods to solve these two major issues. g-C3N4 with a suitable conduction band potential, which is more negative than the electrode potential of H+/H2, is a potential photocatalyst for photocatalytic hydrogen production.However, Sr Ti O3 with the wide band gap is only be excited by UV light, so the utilization rate of the solar light is low. Therefore, more and more people pay attention to design the efficient and stable photocatalyst for photocatalytic hydrogen production.In this paper, we mainly prepared modified Sr Ti O3 composite materials by doping graphene, coupling another semiconductor and surface assisted catalyst modification,to improve photocatalytic hydrogen production performance of Sr Ti O3 composite materials.The as-prepared RGO-Sr Ti O3, g-C3N4/Sr Ti O3 and Ni S/g-C3N4/Sr Ti O3 samples were characterized by transmission electron microscopy?TEM?, X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?, specific surface area test?BET? diffuse reflection spectrum?DRS?, fluorescence spectroscopy?PL? and photocurrent, to investigate the morphology, structure, crystal form, surface properties, light absorption and separation of photogenerated electron-hole of the samples. At the same time, the photocatalytic hydrogen production performance of the samples was tested using the water splitting system. The main research contents of this paper are as follows,?1? RGO-Sr Ti O3 was prepared by hydrothermal synthesis method using tetrabutyl titanate and graphite oxide as raw material. TEM image shows that the diameter of Sr Ti O3 is 100-150 nm and graphene sheet size is at the micron level. The photocatalytic hydrogen production efficiency of Sr Ti O3 is 194.1?mol·g-1·h-1. After graphene doping, the hydrogen production efficiency of RGO-Sr Ti O3 has beenimproved due to the conduction velocity of the photogenerated electron increased after doping of graphene. The hydrogen production efficiency of 0.8%RGO-Sr Ti O3 increased to 363.8?mol·g-1·h-1, which is 1.9 times of that of pure Sr Ti O3.?2? C3N4-Sr Ti O3 was prepared by solvent thermal method using tetrabutyl titanate and urea as raw material. TEM and SEM showed Sr Ti O3 particles were wrapped by g-C3N4 sheet in the g-C3N4/Sr Ti O3 sample, and the size is about 500 nm.Hydrogen production performance and photocurrent measurements showed that 20%g-C3N4/Sr Ti O3 exhibited the best performance. 20%g-C3N4/Sr Ti O3 showed the weakest fluorescence intensity and the best charge separation efficiency. The hydrogen production efficiency of 20%g-C3N4/Sr Ti O3 is 405.7 ?mol·g-1·h-1, which is2.1 times of that of pure Sr Ti O3.?3? Ni S/g-C3N4/Sr Ti O3 was prepared by solvent thermal method using tetrabutyl titanate, urea, nickel acetate and sodium sulfide. The optimal loading amount of Ni S was determined to be 2% by photocurrent testing and hydrogen production performance. The hydrogen production efficiency of Ni S/g-C3N4/Sr Ti O3 increased greatly due to the Ni S loading. The hydrogen production efficiency of2%Ni S/g-C3N4/Sr Ti O3 was 1722.6?mol·g-1·h-1, which was 4.3 times of that of g-C3N4/Sr Ti O3(405.7 ?mol·g-1·h-1). |
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