| Pt-REOx carrier membrane electrode is a applied widely heterogeneous hydrogen evolution catalyst. At present, the key problems of science and technology-Pt-REOx carrier membrane electrode used in high technology fields of new energy, environmental protection and etc.-work out:researching in the new method about short process manufacture of Core-Shell structure membrane electrode; researching in comprehensive control about membrane electrode material, membrane system type, cost performance and energy consumption; researching in Auxiliary catalytic mechanism about oxidation degree and electron transfer way in Rare-Earth (abbr. RE) additives; researching in the structure and performance of membrane electrode through comprehensive control manufacture factors.Consideration of these problems, in this paper, Pt was used as main phase of membrane electrode, Cu was used as alloying element, the oxides of La and Ce were used as cocatalyst, the graphite fiber cloth (abbr. GFC), Si(111) slice and Ni mesh were used as carrier, and dilute H2SO4solution was used as compound in hydrogen evolution performance testing. The Compound multiphase Pt-REOx carrier membrane electrodes (abbr. Pt-REOx MEs)-provided with long-acting, high cost performance, and low-energy were all manufactured by Ion Beam Sputter Deposition (abbr. IBSD) equipment-including with authorized invention patents of author-and Post-processing techniques. The specific research works have:(1) Study on different adulterated amount of Cu and Post-processing techniques influence on PtCu carrier MEs.(2) Study on different membrane system type of La influence on PtCu-La2O3carrier MEs.(3) Study on interaction mechanism between Ce and Pt on surface of Pt-CeOx carrier MEs.(4) Study on manufactured technology influence on Pt-CeOx carrier MEs.After complete these research work, we have acquired some significative experimental results and research conclusions.1. These research results in studying on different adulterated amount of Cu and Post-processing techniques influence on PtCu carrier MEs showed that:(1) The element content distribute equably in PtCu carrier MEs manufactured by IBSD. Along with increasing content of Cu doping, the crystal particle size in PtCu carrier MEs surface was decrease, and membrane organization became densification, and the preferred orientation degree of Pt(111) would be intensified.(2) Through vacuum heat-treatment-at400℃,60min and～10-5Pa, the maximum alloying degree of Pt and Cu was happened in PtCu carrier MEs-about58.7at.%Cu in PtCu carrier MEs was alloyed, and Cu content in PtCu alloy was rised to54at.%, and the crystal particle size in PtCu carrier MEs only had tiny enlargement.(3) After vacuum heat-treatment and acid etching processes-at0.50mol L-1H2SO4solution,30min and50℃, about73.7%Cu in surface of PtCu carrier MEs was separated out, and the dealloying degree in surface than it in inside of PtCu carrier MEs, so, the shell with high concentration Pt was produced and it wrapped outside PtCu alloy particle surface, that was similar core-shell type PtCu@Pt catalyst. The data of Pt-Pt interplanar spacing from HRTEM in fringe area had6.33%decrease than it in core area, and the average crystal particle size had been decreased about16%-from7.93nm fell to6.67nm, and the average specific surface area had been increased about250.2%.(4) The testing data in hydrogen evolution performance of PtCu carrier MEs also indicated that its io had been enhanced respectively11.6%and13.4%after vacuum heat-treatment and acid etching processes, and Ed had been decreased about3%. Therefore, higher alloying degree of PtCu and similar core-shell structure were primary cause result in promoting compositive hydrogen evolution performance of PtCu carrier MEs.(5) It had been accepted by SIPO that the patent for invention-IBSD+Vacuum heat-treatment+Acid etching treatment-relate to short process manufacture similar core-shell structure MEs, and it could control superficial component of PtCu carrier MEs, and it could avoid pollution of intermediate product and reduce energy consumption, and it would be apt to obtain actual application in cheap manufacture hydrogen industry.2. These research results in studying on different membrane system type of La influence on Pt-REOx carrier MEs showed that:(1) It was showed that PtCuLa2O3series monolayer carrier MEs (abbr. PL MEs) had fine homogeneous crystalline grain. Along with the increased doping amount of La, it would be enhanced in PL MEs that the average atomic volume shrinkage degree of Pt5La, thermostability and Oxygen enrichment ability.(2) It would be intensified that the preferred orientation degree of Pt(111) in PtCu/La2O3series bilayer carrier MEs (abbr. P/L MEs), and would be decreased obviously that the average PtCu crystal particle size in La2O3/PtCu series bilayer carrier MEs (abbr. L/P MEs).(3) Its research results indicated that PtCu crystal particle in surface of PtCu/La2O3/PtCu series trilayer carrier MEs (abbr. P/L/P MEs) existed more homogeneous and fine globularity. In addition, after vacuum heat-treatment process-at400℃,60min and～10-5Pa, the testing data in hydrogen evolution performance of P/L/P MEs-at0.50mol L-1H2SO4solution and50℃-indicated that i0>200mA·cm-2,Ed<0.63V, Pt content<0.1mg·cm-2and EAS≥94.172m2·g-1, and its hydrogen evolution performance and performance price ratio were superior to P/L and L/P MEs.(4) Therefore, based on analysis by synthesis of different membrane system type and vacuum heat-treatment technology, it could be manufactured that composite PtCu-La2O3carrier MEs had higher cost performance, lower energy consumption and actual application value.3. Through assaying change in binding energy state of surface atom, the e transfer way on interface could be reflected directly. In this paper, it also had been investigated that the interaction mechanism between Ce and Pt on surface of Pt-CeOx carrier MEs. It could be considered that Ce cation obtained e from Pt, the transfer way of e concurrently have single electron transfer and polyelectrons excitation process. Its innate character was high valence state Ce cation engendered O vacancy get through Oxidation-Reduction cycle of ion-pair-Ce3+/Ce4+, and occurred following e transfer processes: O2+e→O2-→O+O-and O2+2e→2O-4. It was also showed that the research results in studying on manufactured technology influence on Pt-CeOX carrier MEs. There research results indicated that: (1) CeO, Ce6O11, CeO2, Pt2Ce and Pt5Ce had been produced in Pt-CeOx carrier MEs-Ce doped-and Pt(111) peak position in XRD existed negative shift phenomenon.(2) The optimal target position mobile distance (ST) value was20mm, and it would be decreased obviously that the average specific area of Pt-CeOx carrier MEs under overlarge or undersized ST value.(3) After Pt-CeOx carrier MEs were manufactured in room temperature, they had preferential growth of Pt(111), optimal hydrogen evolution activity and lower energy consumption.(4) The optimal flow of high purity O2that had been accessed Auxiliary Deposit Ion Source was8sccm. The preferential growth of Pt(111) would restrain mightily by excessive flow of O2, as well as, the lower flow of O2would impede producing CeOx and Pt-Ce alloy, and then dropped directly concentration of Ce4+.(5) It was indicated that composition and content of CeOx in Pt-CeOx carrier MEs could be controlled effectively through adjusted synthetically energy and current of ion beam. Under3.0kV and60-70mA, the strongest preferential growth of Pt(111) would happen in Pt-CeOx carrier MEs.(6) In the optimal time of actual sputtering deposition-300s, it could be manufactured easily that Pt-CeOx carrier MEs with higher performance price ratio. |
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