Design Of Metal Oxide In₂O₃ Heterojunction System And Study Of Photocatalytic Hydrogen Evolution Performance

In the context of the current energy supply crisis,the development and utilization of solar energy is of great significance in renewable energy production and environmental pollution treatment.Hydrogen is considered one of the cleanest and sustainable sources of energy that could meet the world’s energy needs in the future.Since 1972,Fujishima and Honda first reported the water splitting technology using Ti O₂ photoelectrode for UV light drive,the technology of photocatalytic splitting water to hydrogen production has been rapidly developed,and remarkable achievements have been made in the design and preparation of efficient semiconductor photocatalysts.1.Non-noble metal phosphorescent catalysts have attracted people’s attention for their low price and good photocatalytic efficiency.In this paper,proposed a Co P/In₂O₃ composite catalyst that performs well in hydrogen production.The Eosin Y（EY）-sensitized Co P/In₂O₃ composite catalyst achieved a total hydrogen release of 251.87μmol after 5 h of visible light irradiation,which was three times that of pure Co P under the same conditions.The composite catalyst Co P/In₂O₃ was prepared by physically mixing Co P and In₂O₃ which just need one step.Among them,the Co-MOF（ZIF-9）is used as the precursor to prepare Co P by phosphating method,which maintains the framework structure of Co-MOF.In the Co P/In₂O₃ composite catalyst,the In₂O₃ particles as co-catalyst were tightly attached to the Co P surface,improving the separation efficiency of electron-hole pairs.Subsequent photoelectrochemical experiments also proved the improvement of charge transfer efficiency.2.S-scheme heterojunction is a novel photocatalytic hydrogen production system,which can effectively eliminate useless electron–hole pairs and improve the efficiency of photocatalytic hydrogen production.In this paper,Ni-MOF-P（Ni₂P）/In₂O₃ composite photocatalyst was prepared by a one-step calcined phosphorylation method using Ni-MOF-74 and In₂O₃ as raw materials.The photocatalysts were characterised by various characterisation techniques such as XRD,SEM and XPS,which demonstrated the successful synthesis of Ni-MOF-P/In₂O₃ composite photocatalysts with photocatalytic properties.SEM studies showed that In₂O₃ was excellently compounded on Ni₂P,and the cycling experiments and XRD of the sample after the cycling experiment proved their outstanding stability.The amount of hydrogen evolution with a mass ratio of Ni₂P and In₂O₃ of 1:0.3 was 494.17μmol（within 5 h）,which was 3 times the hydrogen evolution of Ni-MOF-P.In this work,a novel and simple method for preparing non-noble metal phosphides was proposed for photocatalytic hydrogen evolution using a photocatalyst3.In this paper,an innovative Co₉S₈/In₂O₃ composite photocatalyst was prepared by an in-situ grown method.After the composite catalyst loaded with Co₉S₈ on In₂O₃ effectively solved the self-agglomeration effect of In₂O₃ prepared by the method in this work and significantly improved the efficiency of hydrogen production.The useless electrons and holes in Co₉S₈/In₂O₃ were removed more effectively than in the other catalyst,allowing more highly reductive electrons to participate in the hydrogen precipitation reduction reaction due to the formation of S-scheme heterojunctions.The cyclic hydrogen production experiment confirmed that the stability of the composite photocatalyst is excellent,and its 5 h hydrogen production amount reached 277.77μmol.In this paper,a simple synthetic method for the synthesis of composite photocatalysts and novel photocatalysts for the photocatalytic hydrogen evolution of dye-sensitized systems（Eosin Y）is presented.