Preparation And Properties Of Fuel Cell Fe-Based Catalysts

Proton exchange membrane fuel cell(PEMFC)is a kind of ideal renewable energy supply device,in the future it can replace the traditional Power generation equipment with large energy consumption and serious pollution.The catalyst,as one of the main components of a fuel cell,has an important impact on the cost and performance of fuel cells.In recent years,in the fuel cell,platinum and its alloy catalyst has reached a level of maturity,but the high price of platinum and the unstable performance of the catalyst in the acidic electrolyte limit the commercialization of platinum catalyst.So the development of non-precious metal catalyst with cheap and wide source becomes a very good solution.In this paper,cheap polyaniline,melamine,ethylenediamine and phenylenediamine were selected as nitrogen source and graphene was regarded as catalyst support.Loading of transition metal elements prepared high catalytic performance of iron-based catalyst.The main work is as follows:1.By using solution blending and high temperature calcination method,graphene as the catalyst support,polyaniline prepared by different oxidants prepared as the nitrogen source and Fe(SCN)3 as the iron dopant to prepare the electrocatalyst of Fe-S/N(PANI-n)/rGO,Fe-S/N(PANI-h)/rGO and Fe-S/N(PANI-f)/rGO.Through the experiment found that preparation of polyaniline with NaClO as oxidant was the best nitrogen source.Fe-S/N(PANI-n)/rGO and Fe-Cl/N(PANI-n)/rGO were prepared by the addition of different inorganic iron salts(FeCl3,Fe(SCN)3)on nitrogen-doped graphene.The experimental results show that the excellent morphological structure of the catalyst can promote the ORR reaction.The catalytic performance of Fe/N(PANI)/rGO with different iron concentration and different temperature was studied.It was found that when the mass of iron was 1.2%and the pyrolysis temperature was 850?,and the initial potential was 0.829v.Finally,a series of Fe/N(PANI/Cyan)/rGO catalysts with different nitrogen concentrations were prepared,and the type of nitrogen in the catalyst,the number of electron transfer and other properties were analyzed.The results showed that there is not a proportionality between the nitrogen content and the catalytic activity in the catalyst.Only moderate concentration of nitrogen can promote oxygen reduction.2.A series of Fe/N(Mela/EDA)/rGO catalysts were prepared by pyrolysis graphene,melamine and ethylenediamine and ferric chloride.The results show that the mass ratio of melamine to ethylenediamine is 0.2:2,the initial potential of the catalyst is the highest.Co/N(Mela/EDA)/rGO catalyst was prepared by the addition of different quality cobalt chloride on nitrogen-doped graphene in the same way.When the amount of cobalt chloride was 0.025g,the performance of the catalyst was relatively good.The FeCo/N(Mela/EDA)/rGO catalysts with double-doped graphene supported Fe and Co elements were synthesized by the above two kinds of optimization conditions.Find the best metal ratio by experiment.Finally,a series of bimetallic catalysts with different calcination temperatures were prepared.The experimental results show that the 850? was the optimum calcination temperature,and the catalyst has a good initial potential of 0.829v and a large current density.Because at this temperature the coordination effect between the two metals is more obvious.3.Bimetallic BN/FeCo/rGO,SN/FeCo/rGO and PN/FeCo/rGO catalysts of different heteroatoms doped with graphene are prepared.The experimental results show that the doping of B atoms is beneficial to the promotion of ORR.Because the boron atom has the nature of lack of electrons,and the boron atoms into the graphene structure can be more likely to make carbon material defects,so that the charge density generated uneven distribution.These factors are favorable for the adsorption of oxygen molecules.A series of BN/FeCo/rGO catalysts with different B/N ratios were prepared.When the mass of boric acid was 0.05 g,the performance of the catalyst was the best,and the initial potential had reached 0.850v The limiting current density is slightly greater than that of commercial Pt/C catalysts.Finally,a series of B(0.05)N/FeCo/rGO with different temperatures were prepared.The results show that the 850? is the most suitable calcination temperature.