Hydrogen generation utilizing solar energy driven photocatalysts has been recognized as a green and promising way to solve the fossil fuels shortage problem. Therefore, many photocatalysts have been developed for H2 generation through water splitting. The common photocatalysts are only active under ultraviolet light, which occupies only 5% of solar spectrum. Therefore, development of visible-light-driven photocatalysts becomes critical in current photocatalysis research. Metal sulfides have been widely studied as excellent photocatalysts in the visible light range because the valence bands (VBs) were mainly contributed by the S 3p orbitals instead of O 2p in oxides, resulting in higher VB maxima and narrower bandgaps. ZnIn2S4 has a AB2X4 spinel structure with high chemical stability, it is advantageous for metal doping. All photocatalyst were prepared by a simple hydrothermal method. In the photocatalytic hydrogen production experiment, pyrex cell . 40 mL of sollusion containing 40 mg of catalyst, co-catalyst(1wt%) and 0.25 M Na2SO3/0.35 M Na2S mixed sacrificial agent was added into the reaction cell..The light source was a 4500µW/cm2 lamp for 6hours with a cut-off filter (λ ≥ 420 nm). Nitrogen purged through the system for 30 min before reaction to remove oxygen. The concentrations of H2 were measured with a gas chromatograph with TCD. Other characterizations were analyzed with XRD, SEM, TEM, UV-Vis, BET, PL. In photocatalytic hydrogen production under visible light, up to 3600 µmol h−1 g−1 of H2 evolution rate has been achieved over Zn(1-2x)CuxIn2S(4-1.5x)(x=0.06) as a result of trying various combinations of metal doping. This result is 7.6 times higher than that of pure ZnIn2S4. And it was confirmed that photocatalytic hydrogen production using the photocatalyst of this study can be conducted for 24 h continuously. The bandgap of Zn(1-2x)CuxIn2S(4-1.5x) (0 ≤ x ≤ 0.20) decreased from 2.46 to 1.42 eV with increasing the x values and the amount of absorption of light intensity increased by engineering band structure.

Improvement of visible light response photoatalyst ZnIn2S4 based on bandgap engineering with metal co-doping

256th National Meeting (2018)

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