Construction And Properties Of Photocatalytic Decomposition Of Hydrogen Hydrogel System

CdS is the most commonly used catalyst for photocatalytic hydrogen production.It has abundant sources,low cost,narrow optical band gap and strong reducing ability,and has great application potential in photocatalytic hydrogen production.However,the stability of CdS is not strong,and it is easy to cause photocorrosion.By loading CdS NPs on graphene gels and SiO₂ gels,photocatalytic activity of the catalyst is enhanced.A novel composite hydrogel CdS NPs-rGH was synthesized by redox method using CdS NPs and GO.Under sunlight,the CdS NPs-reduced graphene oxide hydrogel（rGH）had the highest hydrogen production rate of 6.44 mmol/g,which is 1.3 times that of CdS nanoparticles（5.12 mmol/g）and 1.4 times that of CdS（4.6 mmol/g）.The enhanced photo-catalytic activity can be attributed to several positive factors.The formation of the composite hydrogel improves the specific surface area of the catalyst and increases the active site on the catalyst surface.The quantum size effects of the CdS NPs effectively reduce the recombination probability of electrons and holes.The close contact between the CdS NPs and the graphene gel can effectively separate photo-generated electrons and holes via the unique large p-bond structure of graphene.In addition,recovery experiments show a composite catalyst recovery rate of up to 95%.The experimental results show that the composite photocatalyst has high recovery efficiency in photocatalytic hydrogen production.The hydrogen production efficiency of the catalyst remains unchanged after 5 cycles indicating that the formation of the gel system stabilizes the catalyst.In further research,polyaniline PANI/CdS NRs-SiO₂ hydrogel（CdS NRs-PANI-SiO₂）was synthesized using CdS NRs as semiconductor.The presence of conductive high-polymer PANI acts as a conductive charge,effectively suppressing the photo-etching of CdS NRs.The addition of SiO₂ hydrogel increases the specific surface area of the catalyst and also facilitates the exposure of the catalyst to more active sites.The experimental results show that the hydrogen production activity of the composite catalyst reaches 43.25 mmol/g under visible light,and the hydrogen production efficiency of the catalyst remains unchanged after 5 cycles.Figure 32;Table 4;Reference 127...