Study Of Several Photocatalysts Properties Of Hydrogen Production From Water Photocatalytic Decomposition Under UV-light Irradiation

With the rapid development of economic and society, resulting in continued increase in energy consumption, some of the traditional energy sources such as coal, oil and other non-renewable energy reserves are limited, so the need to develop new energy sources. In all energy sources, hydrogen has become the ideal of energy because it has a lot of advantages, such as cleaning, non-polluting, renewable, high heat value. Among the many methods of developing hydrogen energy, using solar for photocatalytic decomposition of hydrogen from water is the most economical way to clean.TiO2 had a higher photocatalytic activity to hydrogen generation from water under UV light irradiation. Recently, with the development of nano-materials science, mesoporous materials have been becoming the research highlight because of their special physics and chemistry properties, mesoporous TiO2 with a large surface area and the rules of the pore structure so that presents a higher activity than conventional TiO2 particles in some photocatalytic reaction.Zeolite can improve the photocatalytic efficiency due to its special structure and properties, Zeolite has a large surface area and uniform pore structure, high water thermal stability and through most of the UV and visible light, as a good photocatalyst carrier, TiO2 photocatalysts supported on zeolite can enhance the efficiency of H2 evolution performance of photocatalytic water splitting.The main works focuse on the following aspects:The first part introduced that the principle of water decomposition on photocatalysts is presented, the recent progress in photocatalysts for water decomposition under solar light irradiation is also summarized, and the photocatalyst modification techniques including addition of sacrificial reagent, addition of sodium carbonate, noble metal loading, metal ion doping, anion doping, dye sensitization, semiconductor composition and zeolite-supported to enhance hydrogen production are reviewed。Finally, the development direction of photocatalysts for hydrogen production from water decomposition under solar light in the future is predicted。The second part introduced that we designed and build a set of internal radiation source photocatalytic hydrogen production system, which is connected with gas chromatographic device, can accurately analysis of the composition and content of the gas produced.The third part, mesoporous TiO2 was prepared by hydrothermal method, and the conventional TiO2 particles was prepared by sol-gel method. Their structure and physicochemical properties were charactered by means of XRD, BET, FT-IR. We used the mesoporous TiO2 as the photocatalyst to investigate the light intensity, sacrifice, catalyst dosage and other conditions on photocatalytic properties of hydrogen evolution in order to explore the appropriate reaction conditions. mesoporous TiO2 photocatalysts show higher photocatalytic activity was prepared by hydrothermal method than conventional TiO2 particles was prepared by sol-gel method and Degussa P25 for water splitting to H2 in the presence of 0.1mol/L of Na2S and 0.04mol/L of Na2SO3 under UV-light irradiation of a 250W high-pressure mercury lamp.The fourth part, Ti-SBA-15 with different Ti/Si (mole ratio) and Ce-SBA-15 with different Ce/Si photocatalysts were Synthesized by hydrothermal method. Their structure and physicochemical properties were charactered by means of XRD, FT-IR,UV-Vis DRS, BET, evaluated their activities for water splitting to H2 in the presence of 0.1mol/L of Na2S and 0.04mol/L of Na2SO3 under UV-light irradiation of a 250W high-pressure mercury lamp. The results that these composite mesoporous materials have high surface area to provide more reactivity bit has shown good activity for hydrogen production.The fifth part. Series of nano-TiO2 photocatalysts supported on zeolites (TiO2/zeolite)was prepared by a sol-gel method with four different structure zeolites of Hβ, HMOR, HZSM-5 and HY, The structure and physicochemical properties were charactered by means of XRD, UV-Vis DRS, BET, SEM and SPS. Compared with pure TiO2, the absorptions of the composite photocatalysts were blue -shifted obviously, evaluated their activities for water splitting to H2 in the presence of 0.lmol/L of Na2S and 0.04mol/L of Na2SO3 under UV-light irradiation of a 250W high-pressure mercury lamp. The zeolite-supported nano-sized TiO2 photocatalysts could prevent electron-hole from recombination and enhance the efficiency of H2 evolution performance of photocatalytic water splitting. The photocatalytic performance for hydrogen production is in an order of TiO2/HMOR>TiO2/HZSM-5 >TiO2/Hβ>TiO2/HY>P25>TiO2. The highest hydrogen production amount of TiO2/HMOR is as 1.86 times as TiO2.