Synthesis And Photocatalytic Performance Of Biostructure Carbon/Cadmium Sulfide Composite

Photocatalysis can effectively use sunlight to degrade pollutants or produce clean energy.It is a technology that can solve both energy and environmental crises.Cadmium sulfide,a narrow band gap semiconductor（2.4 e V）,can effectively absorb visible light in sunlight,and is considered as a visible light-responsive photocatalyst with good application prospects.However,pure cadmium sulfide still has shortcomings,such as easy aggregation of particles,serious photocorrosion,high recombination rate of photogenerated electron holes,and low photocatalytic efficiency,which limits its application.Sheet bio-carbon is an amorphous carbon material with special micro-morphology and excellent electrical conductivity.Bio-carbon is cheap and readily available,and it can serve as a support and carrier;the irregular structure on the surface of the material can inhibit the agglomeration during the synthesis of cadmium sulfide.On the other hand,because the precious metal nanoparticles have good nano-size,optical and electrical conductivity,they are supported on the surface of semiconductor photocatalysts,broading prospects in photocatalysis and other fields.By simple hydrothermal and photodeposition methods,bio-carbon/cadmium sulfide and silver-loaded carbon/cadmium sulfide composite materials were prepared.Camellia petals were used as biological templates and carbon sources,and rhodamine B was used as a model pollutant,to study the performance of photocatalytic by degradation experiments under visible light,the main contents are as follows:（1）Bio-carbon/cadmium sulfide composite materials wre synthesized at 180℃with different hydrothermal time（6,8,12,24 h）,and at 180°C,24 h under different solution concentrations（0.05 mol/L,0.10 mol/L,0.15 mol/L,0.20 mol/L）.The products were characterized by structure and phase analysis,and the photocatalytic performance of the resulting material was studied by degradation of rhodamine B.The results showed that the introduction of bio-chabon enhances the absorption of visible light of the composite materials and the photocatalytic performance.The solution concentration has little effect on the performance of the material,but the performance of C/Cd S obtained by different hydrothermal time differs greatly.Within 180 min,the photocatalytic degradation effect of the obtained materials is as follows:C/Cd S-12h（76.72%）>C/Cd S-8h（67.33%）>C/Cd S-6h（37.04%）>pure Cd S（29.69%）.C/Cd S-24h showed the highest photocatalytic performance.The degradation rate of the simulated pollutant rhodamine B（20 mg/L）reached 99.3%within 90 minutes,and the apparent rate constant was-0.03545 min^-1,which was 20 times of pure Cd S.（2）C/Cd S-PVP composites with different PVP addition amounts（0,0.010,0.015,0.020 g）were prepared by hydrothermally introducing polymer PVP at 180℃for 8 h.At the same time,C/Cd S-PVP composites were prepared by adding the same amount of PVP（0.02 g）,hydrothermal 180°C at different time（6,8,12 h）.After characterization,it was found that the addition of PVP is beneficial to improve the regularity of particle morphology.The photocatalytic degradation experiments showed that the photocatalytic degradation efficiency of C/Cd S-PVP composites prepared under the same hydrothermal conditions is significantly higher than that of materials made without PVP.Among them,the material with the added amount of PVP of 0.02 g showed better performance than other materials,and the degradation rate was 77.67%in 180 minutes,which was an increase of about 10%compared with the material without PVP.When the amount of PVP added is the same,the photocatalytic performance of C/Cd S-PVP prepared under different hydrothermal conditions is quite different.C/Cd S-PVP-6h,C/Cd S-PVP-8h,and C/Cd S-PVP-12h were improved by31.96%,10.34%,and 11.83%,respectively.The improvement of the photocatalytic performance of C/Cd S-PVP composites is mainly due to the introduction of polymer PVP,which can greatly improve the dispersion of Cd S particles and increase its specific surface area to provide more reactive sites and reaction centers for photocatalytic reactions..（3）C/Cd S composite material（PVP addition amount of 0.02 g）was prepared under hydrothermal conditions at 180°C for 6 hours,and silver particles were supported on the surface by light deposition to prepare Ag-C/Cd S composite materials.Experiments showed that the photocatalytic degradation effect of Ag-C/Cd S composites is greatly improved.The degradation efficiency of 1wt.%Ag-C/Cd S,5wt.%Ag-C/Cd S and 10wt.%Ag-C/Cd S samples within 180 min reached 91.83%,96.63%and 86.58%,respectively.The 5wt.%Ag-C/Cd S sample showed the highest photocatalytic degradation rate,which was about 7 times that of pure Cd S and 3.9 times that of C/Cd S materials.At the same time,the mechanism of photocatalytic degradation was studied.