Catalytic Oxidation Of Propylene And Propane Over Copper Oxide Nanosheets At Low Temperature

In the past two decades,Chinese economy thrives incessantly,and people’s living standard is gradually improving.But the following environmental problems have gradually emerged.Large amounts of volatile organic compounds(VOCs),which is derived from industrial production,automobile exhaust,indoor building materials,pose a serious threat to the ecological environment and human health.The removal of volatile organic compounds from ambient air and the control of volatile organic compound emissions from source have been recognized as the key to protect the environment.Catalytic oxidation is one of the important technique to remove VOCs pollutants.Noble metal catalysts have the advantages of good activity,low light-off temperature and so on.But their application is limited due to their high cost and deactivation under high temperature.Copper oxide(CuO)is a P-type semiconductor with abundant reserve,low toxicity and harmlessness,and more lattice oxygen so that it has higher activity in catalytic oxidation.The nanosheets structureed CuO has become a research hotspot because of its high specific surface area,controlled exposed crystal facet and more exposed active sites.Herein,different morphology of CuO prepared under different calcination temperatures were investigated.The results of propylene oxidation showed that the CuO nanosheets calcined at 250℃ had the best activity.In order to further improve the catalytic oxidation of propylene and propane as well as the stability of as-prepared catalyst.After experimental investigation,it was found that the CuO nanosheets treated by 0.5M sodium borohydride(NaBH4)will produce oxygen on the surface of CuO.The vacancy further increases the catalytic activity for propylene and propane oxidation,and the sample remains crystal configuration of CuO.Next,we investigate the effect of oxygen vacancy-containing copper oxide nanosheets(CuO-Vo)on the catalytic oxidation of propylene and propane.It has been found that the specific surface area of copper oxide nanosheets with oxygen vacancies increases,which exposes more active sites.It affects the lattice of CuO,and the presence of oxygen vacancies is more likely to adsorb oxygen and increase the flow of lattice oxygen.Compared with CuO nanosheets,CuO-Vo accelerates the catalyst to catalyze the oxidation of propylene,the reaction rate of propane,lowers the temperature of catalytic oxidation reaction,and significantly reduces the apparent activation energy.In summary,the formation of oxygen vacancies on the surface of CuO improves the catalytic oxidation performance of CuO nanosheets to propylene and propane;in addition,the prepared CuO-Vo also shows high stability.