Preparation And Properties Of Semiconductor Metal Oxide ?Cu₂O,ZnO?composites

Metal oxide semiconductor materials are widely applied in the field of photocatalysis,chemical sensing and solar cells due to their unique physicochemical properties and abundant availability.Therefore,to design the semiconductor functional materials with controllable self,efficient and stable has become the focus of the current scientific research.A novel composite heterojunction based on concave cubes Cu₂O-reduced graphene oxide?Cu₂O-RGO?has been synthesized via one-pot hydrothermal method.The anionic surfactant dioctyl sulfosuccinate sodium salt?AOT?can act as the soft template to build the novel Cu₂O microstructure.The ascorbic acid serves as reductant and etching agent in the Cu₂O growing process.The facet etching of Cu₂O and reduction of GO can take place simultaneously in the reaction system.The concave cubes Cu₂O with average edge length of¹.55?m were well-dispersed on the surface of RGO.The Cu₂O-RGO?2 wt%?heterojunction exhibited superior photocatalytic performance and recyclability with the highest amount of H₂ yields of64.3?mol/g,which was 5-fold more than the pure Cu₂O?12.8?mol/g?.The improved photocatalytic performances were attributed to the oxygen vacancies in Cu₂O and a flexible conducting channel supported by RGO.Furthermore,the synergistic effect of Cu₂O and graphene caused broader absorption in visible light region and lower recombination of photogenerated electron-hole pairs.It is believed that the Cu₂O-RGO heterojunction could provide an alternative method to design excellent photocatalysts for energy application.Hierarchical microflowers architecture assembled with 2D porous ZnO nanosheets were fabricated by a one-step solvothermal method and subsequent annealing process.A series of Pd-ZnO have been produced by injecting various volumes of Pd?NO₃?₂·2H₂O solution.The ZnO and Pd-ZnO microflowers are applied to fabricate gas sensors to investigate their sensing characteristics for various gases at different operating temperatures.The 0.05 wt%Pd-ZnO exhibit the highest selective enhancement of acetone?165%?than ammonia?0.9%?,methanal?38%?,methanol?71%?,H₂?35%?and CO?15%?.In addition,it possesses the lower operating temperature and shorter response/recovery times?11 s,5 s?toward acetone gas compared with the pure ZnO microflowers.The spherical Cu₂O-ZnO heterojunction was successfully prepared by controlling the ratio of copper acetate to zinc acetate by hydrothermal method.Characterization of the morphology,chemical structures and optical properties of the prepared materials were investigated by X-ray diffraction?XRD?,field emission scanning and transmission electron microscopy?FESEM and TEM?,EDS and XPS spectra.The effect of the amount of zinc acetate on the morphology were investigated systematically.The results show that the addition of Zn²⁺plays an important role in tuning the morphology of Cu₂O-ZnO heterojunction.With the increase of Zn²⁺addition,the morphology of composites change from octahedral to spherical.Compared with pure Cu₂O?12.5?mol/g?,the photocatalytic activity of the composite?129.6?mol/g?was improved by 10.3 times,which was due to the formation of p-n junction between ZnO and Cu₂O on the surface of material.It is beneficial to the separation of photogenerated electron-hole pairs.Therefore,the photocatalytic performance of the materials could be improved by a successful recombination with ZnO.