Fabrication Of TiO₂-Cu/Ni Catalytic System And Its Photocatalytic Hydrogen Evolution Properties

TiO2 is used widely in the field of photocatalysis and so on as a semiconductor with excellent properties. But the shortcomings of the wide band gap、not absorbing visible light and the recombination of photoinduced electron-hole of TiO2 reduce its application efficiency in the use of solar energy and cannot satisfy the practical use. Nowdays the commonly used and the effective way is to use noble metal as cocatalyst to improve the photoinduced electron-hole separation. Hower, noble metal is expensive and the storage is rare, so that it is not suitable for use in the large-scale industrial production. Therefore, we should develop a cheap, simple and easy gotten environmental friendly cocatalyst.In the research, we choose TiO2 as the main catalyst and Cu、Ni alloy as cocatalyst and we fabricate TiO2-Cu/Ni and eosin-TiO2-Cu/Ni photocatalytic systems. Besides, the samples we prepared were measured through XRD、TEM、XPS and EDX. Baesd on the above, we evaluate the photocatalytic system according to photocatalytic hydrogen evolution activity and the factors including the hydrothermal reaction temperature, hydrothermal reaction time, pH, content of Cu-Ni, the molar ratio of Cu and Ni, dosage of photocatalyst and concentration of sacrificial reagent on the hydrogen evolution. At last, the photocatalytic hydrogen production mechanism of the catalytic system has been preliminary discussed through electrochemical method. We can find from the research:(1) we load Cu/Ni alloy on TiO2 nanoparticles through in situ reduction method and existence of Cu/Ni alloy loaded on TiO2 nanoparticles is Cu/Ni@Ni core-shell structure.(2) The TiO2-Cu/Ni photocatalytic system fabricated is an efficient catalyst in photocatalytic hydrogen evolution over wate reduction. The highest hydrogen production rate of the catalyst can be up to 13.5 mmol g-1 h-1.(3) The high photocatalytic activity of TiO2-Cu/Ni might be ascribed to the synergistic effect between Cu and Ni. The theory is that the alloying of Cu and Ni makes the height of the Schottky barrier suit for the transfer of photoinduced electron form TiO2 to metal cocatalyst. Hence, this promotes the separation of electron-hole efficiently.(4) The use of eosin can effectively expand the working wavelengths of TiO2-Cu/Ni photocatalytic system to the visible area. The prepared eosin-TiO2-Cu/Ni photocatalytic system is an efficient visible light catalytic hydrogen production catalysts. Under the best coditions, the rate of hydrogen evolutiois up to 2.51 mmol g-1 h-1.(5) Alloy of Cu/Ni is a high efficient cocatalysts for TiO2 nanoparticles. It is expected to replace Pt in the further design and development.