Preparation Of Graphene Based Perovskite-type Nanocrystaline Films And Their Photocatalytic Actinvity

Perovskite has been widely studied as a photocatalyst due to its stable structure andexcellent performance. Graphene was discovered in recent years, and as-synthesizedgraphene was a new type of two-dimensional carbon nanomaterials. Nano-composite filmswere prepared by compositing between perovskite and graphene. It produces novelsynergies, while there is no secondary pollution and facilitate recycling reuse, promote itspractical application in photocatalytic aspects, therefore, it has broad application.This article prepared graphite oxide by improved Hummers method, and restored thegraphite oxide by thermal stripping and hydrazine hydrate to obtain graphene material.The thickness of graphene was measured by atomic force microscopy; the surface areawas measured by BET analyzer; the surface morphology was observed by scanningelectron microscopy. The results show that the thickness of graphene was about2nm, thesurface area was443m2/g and the pore distribution concentrated at about2.5nm. Thestructure of graphene was honeycomb, it can spread out after sonication.The surface of glass sheets was modified by3-aminopropyl triethoxysilane(APTES).After modification, the contact angle of glass sheet was reduced from41.7°to7.5°. Themodified glass was used as substrate by sol-gel method combined with spin-coatingtechnique to prepare LaMnO3/graphene composite films, La1-xSrxMnO3/graphene(x=0,0.05,0.1,0.15) composite films and LaMn1-xCoxO3/graphene(x=0.1,0.15,0.2) compositefilms. The gel precursor decomposition process of perovskite/graphene composite wasanalysed by DTA-TG technology, the was analysed by X-ray diffraction and calculatedthe particle size, the surface morphology and the thickness of composite films wereobserved by SEM.The results show that LaMnO3which size was about20nm had grown on the graphenesheets uniformly, the composite sol can be uniformly spread on the glass substrate and thethickness of four films was about960nm.Through the photocatalytic degradation of different dyes to determine the optimalcontent of graphene and the best substitution of Sr or Co. Discussed the photocatalytic degradation mechanism of composite films and compared with TiO2film. The resultsshow that LaMnO3/graphene composite films had the best photocatalytic property whenthe mass fraction of graphene was2%, the composite films had the best effect of thephotocatalytic when the substitution amount of Sr was0.1or Co was0.15, and comparedwith TiO2, the photocatalytic performance increased10.3%or16.2%, respectively.