Preparation Of Indium Oxide （In₂O₃）-based Nanocomposites And Its Performance For Photocatalytic Hydrogen Production Coupled With Organic Pollutants Degradation From Wastewater

With the accelerated pace of industrialization and rapid population growth,the energy crisis and environmental pollution are becoming increasingly serious.Vigorously developing renewable new energy and solving the energy crisis and environmental pollution problems from the source have attracted widespread attention.Hydrogen（H₂）is an efficient and clean“carbon-free”energy source with very high energy density compared to traditional fossil fuels,and has been considered an ideal candidate fuel for economic and social sustainable development.Photocatalytic splitting water for hydrogen production coupled with organic pollutant degradation technology can use organic pollutants as sacrificial agents to promote the hydrogen production process,and can realize the production of hydrogen energy while solving the problem of environmental pollution.Among many semiconductor materials,Indium oxide（In₂O₃）semiconductor material has the advantages of suitable energy band structure,excellent photochemical stability,low toxicity,etc.,and has been widely studied in the field of photocatalysis.However,the photocatalytic activity of a single In₂O₃is severely limited,mainly due to the low rate of separation and transfer of photo-induced electron-hole pairs.Co-catalysts can provide active sites and greatly accelerate interfacial charge transport,which is a common strategy to modify In₂O₃to improve its photocatalytic activity.At present,the modification of In₂O₃with noble metals such as platinum（Pt）,gold（Au）,and silver（Ag）as co-catalysts has attracted extensive attention.However,these precious metals are expensive and naturally scarce,and are not suitable for large-scale promotion and use in large-scale production.Therefore,it is of great significance to find cheap and low-cost non-noble metal co-catalyst to improve the photocatalytic activity of In₂O₃.In this paper,two different non-noble metal co-catalysts were used to modify In₂O₃to increase the photocharge separation and migration rate of the catalyst,and improve the performance of photocatalytic hydrogen production coupled with organic pollutants degradation.A series of characterizations were used to study the morphology,microstructure,composition,specific surface area and photoelectric properties of the as-prepared photocatalysts.Then,the photocatalytic activity and stability of the composites were investigated by using photocatalytic hydrogen production coupled with organic pollutants degradation from wastewater,and the photocatalytic reaction mechanism was also discussed.The specific research contents of this paper are as follows:（1）A novel zero-dimensional/three-dimensional（0D/3D）nickel phosphide（Ni₂P）/In₂O₃nanocomposites were synthesized by a simple hydrothermal method.The photocatalytic activity of Ni₂P/In₂O₃nanocomposites were investigated by photocatalytic hydrogen production coupled with rhodamine B（Rh B）degradation experiments.Through various physical and chemical characterization methods,it was found that 0D Ni₂P nanoparticles were successfully loaded on the surface of 3D In₂O₃nanocubes.Meanwhile,compared with pure In₂O₃,the as-synthesized nanocomposites had faster photogenerated charge transfer and separation rates and extended photocharge lifetime.Photocatalytic experiments showed that the as-formed nanocomposites can improve the photocatalytic hydrogen production coupled Rh B degradation performance,among them,when 7 wt%Ni₂P nanoparticles were loaded with In₂O₃（7-Ni₂P/In₂O₃）,the as-obtained nanocomposite had the best performance.The hydrogen production rate and Rh B degradation rate reached 1.4μmol g^-1h^-1and 16.1%,respectively,which were10.6 times and 1.6 times higher than those of pure In₂O₃.In addition,the 7-Ni₂P/In₂O₃photocatalyst exhibited good photostability under long-term light conditions,and its photocatalytic activity is also better than that of In₂O₃supported by 1 wt%Pt under the same experimental conditions.（2）A novel two-dimensional/three-dimensional（2D/3D）molybdenum disulfide（MoS₂）/In₂O₃nanocomposites were successfully synthesized by a simple hydrothermal method.The photocatalytic performance of MoS₂/In₂O₃nanocomposites were evaluated by photocatalytic hydrogen production coupled with Rh B degradation experiments.Through various physical and chemical characterization methods,it was found that 2D MoS₂nanosheets were successfully loaded on the surface of 3D In₂O₃nanocubes,and at the same time,compared with pure In₂O₃,the as-synthesized nanocomposites had faster photogenerated charge separation rate,more large specific surface area and reduced charge lifetime.Photocatalytic experiments showed that the as-formed nanocomposites can improve the photocatalytic hydrogen production coupled Rh B degradation performance,among them,when 10 wt%MoS₂nanosheets were loaded with In₂O₃（10-MoS₂/In₂O₃）,the as-obtained nanocomposite exhibited the best photocatalytic hydrogen production coupled with Rh B degradation performance,and the hydrogen production rate was 15.5μmol g^-1h^-1,which was 77.5 times higher than pure In₂O₃.Meanwhile,the Rh B photodegradation efficiency of 10-MoS₂/In₂O₃is close to 100%,and the total organic carbon removal rate(η_TOC)is 12.1 times higher than that of single In₂O₃.In addition,the cyclic experimental results show that the 10-MoS₂/In₂O₃photocatalyst exhibits good photostability,and its photocatalytic activity is is much better than that of 1 wt%Pt and 1 wt%Au supported under the same experimental conditions.