Synthesis And Water Splitting Properties For(Ga_1-xZn_x)(N_1-xO_x) Solid Solution Thin Film

With the rapid development of modern industry, the demand for energy beingcontinuously increasing, however, traditional energy reserves is limited, so thedevelopment and use of new energy has become a problem for us. Solar energy hasthe advantages of being wide distribution, inexhaustible and inexhaustible, is a kindof good new energy to meet the human demand, while hydrogen energy is a kind ofno pollution, easy storage and high combustion heat energy, so converting solarenergy into hydrogen energy has become a promising way to meet the solar energyutilization.Since Fujishima and Honda reported the phenomenon of using semiconductor asa photo anode decomposition of water into hydrogen in1972, a lot of photocatalystsfor water splitting have been found, but most of them can only absorb the light of theultraviolet region, can not make good use of the sun.(Ga1-xZnx)(N1-xOx) solidsolution is a good kind of photocatalyst for water splitting catalyst, the bottom of theconduction band for (Ga1-xZnx)(N1-xOx) is mainly composed of4s and4p orbitals ofGa, while the top of the valence band consists of N2p orbitals followed by Zn3d andO2p orbitals. The function of p-d repulsion shifts the valence-band maximumupward without affecting the conduction-band minimum. Obviously, the band gapenergies of (Ga1-xZnx)(N1-xOx) decreases, makes the solid solution has a certainabsorption in the visible light region. After depositing proper cocatalyst on thesurface of the catalyst, the catalytic performance of the catalyst will be multiplied upgrade.In this thesis, we firstly coat a layer of thin film of (Ga1-xZnx)(N1-xOx) solidsolution on the surface of quartz glass plates, exploring the optimal growthconditions. Followed we deposit Rh-Cr2O3core-shell structure cocatalytic on thesurface of the solid solution. At last, we do some tests to reveal the properties of themorphologies, the crystal structure and the optical characterization of the(Ga1-xZnx)(N1-xOx) solid solution. And then we test it’s catalytic efficiency of watersplitting. The specific work is as follows:(1) We take the Zn(NO3)2and Ga(NO3)3as the precursor, with propylene glycolas solvent, put the paste on the quartz glass by scraping method, after hightemperature nitriding we get (Ga1-xZnx)(N1-xOx) solid solution films.Compared withtraditional powder photocatalysts for water splitting, the solid solution film is moreeasily recycled, no residues in water, to achieve environmental protection and thepurpose of saving cost.(2) After studying we find the different ratio of precursor and different nitridingtemperature solid solution will have influence on the solid solution. The precursoratomic ratio of Zn:Ga=1:1, nitriding temperature850℃is the best condition toprepare solid solution. On this condition, the absorption edge of the solid solution is415nm,the particle size of solid solution is50-100nm and the thickness of the film isabout15μm.Throngh EDS, we conclude that the content of Zn is7%, means thesolid solution is (Ga0.93Zn0.07)(N0.93O0.07). The catalytic efficiency of the solidsolution is2.2μmol/h。(3) In order to improve the catalytic efficiency, we deposit Rh-Cr2O3core-shellstructure cocatalytic on the surface of the solid solution. When the deposition of Rhreachs3times and the deposition Cr2O3reachs4h, the catalytic efficiency catchs themaximum,12.5μ mol/h.According to the HRTEM graph we can see, the Rh coresize is3-5nm and the Cr2O3shell thickness of about2nm. After testing on the samesample, its catalytic activity without significantly decreased, indicating that thesamples are of high stability.