The Synthesis And Performance Of Zinc And Cobalt Compound Photocatalyst

For energy and environmental problems which hinder the progress of society,human make great efforts to search solutions in all fields.As a kind of green and sustainable energy conversion technology,photocatalytic technology has become the research hotspot in scientific work so far.It could not only transform solar energy to other forms of energy?hydrogen energy etc.?,but also degrade most of pollutants,which provides a best way to solve the two problems at same time.As photocatalysts,the hydrotalcite structure of Zn?OH?₂ and the brucite structure of ?-Co?OH?₂ have wider band gap and lower activity,restrictin their application in visible light.But of the composites of two materials,would be used in photocatalysis field.In this paper,the microwave-assistance synthesis Zn?OH?₂/?-Co?OH?₂ photocatalyst put into use in photocatalytic hydrogen production and the adsorption of organic dyes.Two different kinds of photocatalysts were synthesized using calcination and adsorption-calcination,respectively,and applied to degrade organic dyes.And its activity were evaluated.The following are main conclusion:1)Zn?OH?₂/?-Co?OH?₂ photocatalysts were synthesized by microwave hydrothermal method and were used in the photocatalytic hydrogen production.Reaction conditions were changed,such as component ratio of zinc to cobalt,microwave temperature,alkali source,synthetic method,they influenced photocatalytic activity of the photocatalyst for hydrogen under UV light.Other than ?-Co?OH?₂ as co-catalyst,the main innovation point in this experiment is that?-Co?OH?₂ could be used as main-catalyst,and the synergistic effect of Zn?OH?₂ and ?-Co?OH?₂ observed in hydrogen production.The zinc-cobalt hydroxide photocatalyst?Zn:Co=1:2?synthesized through microwave hydrothermal at 120? with the aid of NaOH has high photocatalytic activity,and the hydrogen generation rate is 67 mmol·h-1·g-1 under UV light with Na2SO3 as sacrifice agent.It has good hydrogen production stability.2)Zinc-cobalt hydroxide synthesized by microwave hydrothermal has great chemical absorption of cationic dye?RhB and MB?.The Zinc-cobalt hydroxide synthesied with microwave-assistance has higher adsorption of MB than that prepared by coprecipitation method and hydrothermal method.When the molar radio of zinc to cobalt is 1:2,MB absorption by Zn?OH?₂/?3-Co?OH?₂ is the best and reaches to 462.65 mg/g.3?ZnO??-Co?OH?₂ and Zn?OH?₂/?-Co?OH?₂?Zn:Co=1:2?Samples obtained by microwave-assisted thermal method were calcinated after adsorption of organic dye MB and the calcinated samples were used as photocatalysts in the degradation of MB.The calcinated was conducted in a muffle furnace at 450? for 2 h.The degradation reaction contained 100 ml of methylene blue solution?30 mg/L?5 mg of the catalyst.It was found that the samples prepared with the adsorption MB of ZnO had higher degradation activity compared to other samples,with 91%of methylene within 2 h.