Studies On Preparation And Photocatalytic Properties Of Free-Standing And Flexible Cu-based Heterojunction Net

In recent years,due to the fast global urbanization and industrialization,human beings have been facing the worldwide deepening water-contamination and water-shortage crises.Photocatalysis,which can harvest the inexhaustible solar energy for water purification,is recognized as a promisingly environment-friendly and economical approach to tackle this issue.Moreover,photocatalysts can completely mineralize most toxic organic contaminants into nontoxic CO₂ and water.Howerver,tedious fabrication process and difficult recovery of photocatalysts have greatly limited the practical use of the photocatalysis technology.In this dissertation,free-standing and flexible Cu-based heterojunction nets with easy recovery property were simply developed,and their photocatalytic performance was explored.To tackle the expansive separation issue of photocatalysts,flexible 3D Cu@CuI core-shell mesh was simply fabricated by one-step in situ iodination of copper mesh at an ambient temperature.The novel 3D Cu@CuI core-shell structure allowed for high electron/hole separation and thus leads to ultra-high photocatalytic efficiency under UV light irradiation.The iodination conditions were found to affect the performamce of Cu@CuI mesh,and the optimal iodine quality,iodinate temperature and time were 1 g,25 ^oC and 1 h,respectively.More importantly,the 3D Cu@CuI mesh was freestanding and flexible,and therefore was easily separated from water after photocatalysis without causing secondary pollution.Free-standing and flexible Cu/Cu₂O/CuO heterojunction net was successfully fabricated by one-step calcination in air using Cu net as the matrix.The mixing narrow band gaps of the Cu/Cu₂O/CuO heterojunction not noly ensured its wide absorption band in visible region but also allowed for effective electron/hole separation,thus leading to excellent visible-light photocatalytic performance.It was found that calcination parameters played an important role on the photocatalytic activity of Cu/Cu₂O/CuO heterojunction net,and the optimal calcination temperature and time were 500 ^oC and 9 h,respectively.In addition,as for the one-step,low-cost and facile fabrication,the Cu/Cu₂O/CuO heterojunction net was well suited to scale-up production.