Presentation Information
[PY1-44]Artificial solid Z-Scheme system MWO4/Pt/CdS (M=Co, Ni, Zn) for effective photocatalytic H2 generation
○Mingjie Li1, Shun Yokoyama1, Hideyuki Takahashi1, Kazuyuki Tohji1 (1. Tohoku university)
Keywords:
Photocatalysis,Z-scheme system,Metal tungstate,Hydrogen generation
Artificial solid Z-scheme system, imitating the natural photosynthesis system, has attracted much interest due to its property of maintaining holes and electrons at high redox potential. Recently, metal tungstate (MWO4) has caused much attention because of its appropriate bandgap and interesting physicochemical properties. High efficiency solid Z-scheme system CdWO4/CdS has been reported. However, the bandgap of CdWO4 (3.64 eV) is too large for visible light absorption. Other MWO4 have suitable bandgaps (indirect bandgap: NiWO4, 1.82 eV; CoWO4, 1.80 eV; ZnWO4, 3.14 eV), but their photocatalytic applications are not yet explored. Therefore, the purpose here is to utilize MWO4 as PS2 to fabricate novel solid Z-scheme systems for photocatalytic H2 generation.
MWO4/Pt/CdS (M=Co, Ni, Zn) were fabricated in 3 steps. MWO4 were synthesized by reaction between M(NO3)2 and Na2WO4. Then platinum was modified on MWO4 through the reduction of H2PtCl6 by NaBH4. Finally, CdS was synthesized on MWO4/Pt through the reaction between Cd(CH3COO)2 and CH3CSNH2 in MWO4/Pt aqueous suspension. During this step in synthesis of NiWO4/Pt/CdS, CH3CSNH2 were 0.014, 0.042, 0.07 g and the samples were labelled as NWCS1, NWCS2, NWCS3 respectively. Photocatalytic reactions were taken in lactic acid solution under 550 W Xenon lamp.
Photocatalytic H2 generation of NiWO4/Pt/CdS, CoWO4/Pt/CdS, ZnWO4/Pt/CdS were 17.5, 15.8, and 4.4 mL/2 h respectively. As bandgap of ZnWO4 is much larger than those of NiWO4 and CoWO4, the low performance of ZnWO4/Pt/CdS may be induced by the low charge separation rate of ZnWO4 under visible light. Ratio of S increased and W decreased with the increase of CH3CSNH2 concentration from NWCS1 to NWCS3. The result indicated that S2–concentration has an effect on the elemental composition of the photocatalysts obtained.
Another results will be presented in our session.
MWO4/Pt/CdS (M=Co, Ni, Zn) were fabricated in 3 steps. MWO4 were synthesized by reaction between M(NO3)2 and Na2WO4. Then platinum was modified on MWO4 through the reduction of H2PtCl6 by NaBH4. Finally, CdS was synthesized on MWO4/Pt through the reaction between Cd(CH3COO)2 and CH3CSNH2 in MWO4/Pt aqueous suspension. During this step in synthesis of NiWO4/Pt/CdS, CH3CSNH2 were 0.014, 0.042, 0.07 g and the samples were labelled as NWCS1, NWCS2, NWCS3 respectively. Photocatalytic reactions were taken in lactic acid solution under 550 W Xenon lamp.
Photocatalytic H2 generation of NiWO4/Pt/CdS, CoWO4/Pt/CdS, ZnWO4/Pt/CdS were 17.5, 15.8, and 4.4 mL/2 h respectively. As bandgap of ZnWO4 is much larger than those of NiWO4 and CoWO4, the low performance of ZnWO4/Pt/CdS may be induced by the low charge separation rate of ZnWO4 under visible light. Ratio of S increased and W decreased with the increase of CH3CSNH2 concentration from NWCS1 to NWCS3. The result indicated that S2–concentration has an effect on the elemental composition of the photocatalysts obtained.
Another results will be presented in our session.