SnO₂ -TiO₂ structures and the effect of CuO, CoO metal oxide on photocatalytic hydrogen production

Abstract

BACKGROUND The technology for generating hydrogen using a photocatalyst has attracted considerable attention. Coupling TiO2 with other semiconductor oxides provided excellent results in decreasing recombination by transferring one of the charge carriers to another oxide. These photogenerated charge carriers play key roles in the reduction and oxidation process in photocatalytic hydrogen production. Nevertheless, even if the (e−‐h+) are separated, the reaction cannot happen without proper active sites. So, co‐catalysts are needed to improve the reduction and oxidation process on the surface of photocatalyst. RESULTS The hydrogen production of SnO2@TiO2 structure with CuO and CoO co‐catalysts (1 wt% of co‐catalyst: 1Co‐ST, 1Cu‐ST and 1Co‐1Cu‐ST) was studied under UV light, and characterized by XRD, N2 adsorption, UV‐vis reflectance diffuse, XPS and photoelectrochemical test. The dispersion of co‐catalyst on the surface of ST material during impregnation generates a decrease in the surface area and defect states in the optical properties. Maximum hydrogen production rate 1486.4 µmol g−1 h−1 is observed on 1Co‐1Cu‐ST photocatalyst. This improvement in photocatalytic reaction is related to the role played by each co‐catalyst. CONCLUSIONS The photocatalytic activity for H2 evolution shows the role of co‐catalyst in the redox reactions process. In the case of CuO co‐catalyst, it helps charge transfer, specifically electrons, to be carried out more efficiently by reducing water to produce H2. On the other hand, the role of CoO co‐catalyst is to catalyze the oxidation process, improving charge carriers separation and providing electrons to the SnO2@TiO2. © 2017 Society of Chemical Industry

Comprehensive review and future perspectives on the photocatalytic hydrogen production

“…However, the energy consumption associated with electrolysis must be significantly reduced before this process becomes competitive at large scales. Photocatalytic generation of H 2 from organic solutions or H 2 O, although considered a minor source in terms of produced H 2 volume, appears to be a complementary and renewable way for simultaneous H 2 generation and wastewater remediation …”

“…A wide variety of semiconductor photocatalysts has been investigated so far, such as chalcogenides (ZnS, CdS, CdSe), metal oxides (TiO 2 , Cu 2 O, ZrO 2 ), carbonaceous materials (g‐C 3 N 4 ) and solid solutions [(Ga 1‐x Zn x )(N 1‐x O x ), (AgIn) x Zn 2(1‐x) S 2 ] . However, TiO 2 is still the most widely used photocatalyst because of its good stability in a wide range of pH conditions, resistance to photo‐corrosion, nontoxicity and commercial availability.…”

Recent advances in two‐dimensional transition metal dichalcogenides as photoelectrocatalyst for hydrogen evolution reaction

“…99 However, the energy band alignment of TiO 2 is not suitable for efficiently producing hydrogen through photoreduction reaction. [100][101][102][103][104] On the contrary, the absorption of 2D-TMDs is weak; however, the band alignment is suitable for the redox potential of water. Therefore, the composites formed by 2D-TMDs with TiO 2 are expected to be promising catalysts for highperformance PEC-HER.…”

Ga2O3/TiO2 semiconductors free of noble metals for the photocatalytic hydrogen production in a water/methanol mixture

“…The efficiency of H 2 production depends on the extent of light absorption, charge separation and migration, charge utilization at redox sites, and the integration of all these factors in an efficient way . Deposition of noble metals, and modification of TiO 2 with semiconductor oxides, such as SnO 2 , CuO and WO 3 , have been successfully prepared to diminish their disadvantages . Gallium oxide (Ga 2 O 3 ) is a representative of d 17 metal oxides.…”