A carbon-supported core-shell dense copper-iron-copper-platinum catalyst for fuel cells

Abstract

The invention relates to a carbon-loaded core-shell dense copper-iron-copper-platinum catalyst for fuel cells, which belongs to the field of electrochemical technology; it is composed of carrier carbon and active components, and the active component is copper-iron-copper-platinum with dense surface layer Core-shell structure, in which the copper-iron alloy is the core, the copper layer is the subsurface layer, and the platinum layer is the dense shell layer; its raw material mass percentage composition is: carrier carbon: 60%-80%, copper: 12-17%, iron: 2 ~3%, platinum: 6~20%. The present invention adopts the mixed solution of ethylene glycol and sodium borohydride as reducing agent to prepare copper-iron alloy inner core at normal temperature, uses dilute hydrochloric acid to remove the unalloyed iron on the inner core surface to form copper subsurface layer, and adopts ethylene glycol microwave to assist reduction of chlorine Platinum acid deposits platinum on the outermost layer, and finally undergoes high-temperature annealing treatment to obtain a dense three-layer core-shell copper-iron-copper-platinum catalyst. The catalyst prepared by the invention has the advantages of low platinum loading, good catalytic activity and high chemical stability, and will promote the further development of fuel cells.

Description

technical field [0001] The invention relates to a catalyst for fuel cells, in particular to a carbon-supported core-shell dense copper-iron-copper-platinum catalyst (Cu-Fe@Cu@Pt / C) for fuel cells, which belongs to the technical field of electrochemistry. [0002] technical background [0003] Proton exchange membrane fuel cells (PEMFCs) are devices that directly convert chemical energy into electrical energy. They have received extensive attention in recent years due to their high efficiency and environmental friendliness. However, the lack of resources and high price of platinum in battery materials restrict the commercialization of proton exchange membrane fuel cells (PEMFCs). [0004] At the anode of proton exchange membrane fuel cells (PEMFCs), hydrogen is oxidized to generate electrons and hydrogen ions, which are transferred to the cathode through an external circuit and proton exchange membrane, respectively. At the cathode, oxygen is reduced by reacting with hydrogen...

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Problems solved by technology

At 40,000 potential cycles (0.65 to 1.05 volts, 100mVs -1 ), the fuel cell performance of the Pd@Pt core-shell catalyst was significantly improved (at 600mA cm -2 70mV), and the mass activity is 4.5 times that of commercial platinum-carbon catalysts, but the price of palladium as the core is relatively expensive, and the lattice mismatch with platinum is small, and suitable lattice stress cannot be formed, which limits the further improvement of activity

[0007] Using a proprietary method, Ball et al. deposited platinum (Pt) shells on Pd-Co alloy nanoparticles and achieved 0.7A mg -1 High quality activity, the improvement of activity is due to the doping of transition metal into the core of palladium, fine-tuning the electronic structure of platinum, and the transition metal with smaller particle size in the structure forms an alloy with platinum in the subsurface layer, which improves the activity and stability , but the cobalt atom is relatively active and easily dissolved in an acidic environment, destroying the structure of the catalyst, and the simple core-shell structure can no longer meet the stability requirements of fuel cells

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