| Solar energy is an abundant and clean renewable energy, which is a promise energyresource for future. The production of clean, low-cost, and environmentally firendlyhydrogen fuel by solar energy conversion has been considered as a prospective strategyfor solving the global energy problem. Using photoelectrochemical (PEC) cell to splitwater appears to be an attractive technology for H2production. Preparing the photoelectrochemically stable semiconductor electrodes is one of the key-points in thistechnology. Many kinds of semiconductor mateirals have been investigated，such asTi02, GaP, CuInSe2and so on.Cu2ZnSnS4(CZTS) possesses promising characteirstic optical properties, withband-gap energy of about1.5eV that is very close to the optimum value for being usedas an absorbed layer in solar cells and large absorption coefficient in the order of101cm". And thus, it is one of the promising candidate materials for low cost absorber layerin thin film solar cells and the photo cathode in PEC reaction. Moreover, this quaternarycompound does not contain toxic elements or expensive rare metals and the elements itcontained are abundant in the crust.To avoid using vacuum equipments, we tired to prepare CZTS films by bothsingle-step electrochemical deposition method and sol-gel method. Base on thesuccessfully preparation of CZTS films on two different substrates (FTO glass,molybdenum) by the sol-gel method, the influence of substrates on thephotoelectrochemical property of CZTS iflms in the reduction of Eu(NC>3)3and waterwere investigated.M0S2is a kind of layered semiconductor material similar to graphene structure,which has been identified as a promising hydrogen evolution catalyst with catalyticactivity edge points. In the past twenty years, the potential application of M0S2materialsin catalysis, hydrogen storage mateiral, Lithium ion electrode materials, etc raised muchconcerns. We discussed the M0S2catalytic activity for the hydrogen evolution in waterpreliminary.The main work includes the following several parts:1、Preparation and characteirzation of CZTS iflms(1) We deposited CZTS on FTO glass by single-step electrodeposition method,XRD and XPS were used to examine the structure and composition of CZTS. We foundthat it was difficult to deposit the four elements largely at the same potential simultaneously.(1)Firstly, we tried to deposit CZTS on FTO glass by single-step electrodepositionmethod. The structure and composition of the products were investigated by XRD andXPS methods. We found that it was dififcult to deposit the four elements largely at thesame potential simultaneously.(2)We successfully deposited CZTS on two substrates (FTO glass, molybdenum)by sol-gel method. The structure, morphology, composition and optical properties of thefilms were analyzed by XRD, Raman, FE? SEM, EDX, ICP, UV-visablespectra?respectively. All the results are agreed with the published papers.2、Photoelectrochemical properties of CZTS films(1)CdS buffer layer and Pt were further modified on the surface of CZTS iflms bychemical deposition method and electrochemical deposition method respectively. Wecompared the photoelectrochemical properties of the bare CZTS electrodes and themodified CZTS electrodes in th3e reduction of Eu+and water.(2)We investigated the photoelectrochemical properties of Pt/CdS/CZTS/FTO andPt/CdS/CZTS/Mo in the water splitting experiment. Results showed that the onsetpotential of the cathodic photocurrent increased with increasing pH. The onset potentialof the cathodic photocurrent on Pt/CdS/CZTS/FTO electrode is signiifcantly morepositive than that on Pt/CdS/CZTS/Mo electrode.3、 M0S2as catalyst for hydrogen evolution in waterM0S2was prepared by ultrasonic stripping method, compared the differentproperties between the bare glassy carbon electrode and the MoS2.modiifed glassycarbon electrode in the reduction of water. The reduction current is bigger and the onsetpotential is more positive when the M0S2was modiifed. |
PDF Full Text Request