Secondary reduction strategy synthesis of Pt-Co nanoparticle catalysts towards boosting the activity of proton exchange membrane fuel cells

Based on the volcanic relationship between catalytic activity and key adsorption energies,Pt-Co alloy materials have been widely studied as cathode oxygen reduction reaction(ORR)catalysts in proton exchange membrane fuel cells(PEMFCs)due to their higher active surface area and adjustable D-band energy levels compared to Pt/C.However,how to balance the alloying degree and ORR performance of Pt-Co catalyst remains a great challenge.Herein,we first synthesized a well-dispersed Pt/Co/C precursor by using a mild dimethylamine borane(DMAB)as the reducing agent.The precursor was calcined at high temperature under H_(2)/Ar mixed gas by a secondary reduction strategy to obtain an ordered Pt_(3)Co intermetallic compound nanoparticle catalyst with a high degree of alloying.The optimization of elec-tronic structure due to Pt-Co alloying and the strong metal-carrier interaction ensure the high kinetic activity of the cell membrane electrode.Additionally,the high degree of graphitization increases the electrical conductivity during the reaction.As a result,the activity and stability of the catalyst were significantly improved,with a half-wave potential as high as 0.87 V,which decreased by only 20 mV after 10000 potential cycles.Single-cell tests further validate the high intrinsic activity of the ordered Pt_(3)Co catalyst with mass activity up to 0.67 A mg_(pt)^(-1),exceeding the United States Department of Energy(US DOE)standard(0.44 A mg_(pt)^(-1)),and a rated power of 5.93 W mg_(pt)^(-1).

Synthesis of cobalt, palladium, and rhenium nanoparticles

Over the past decade,metal nanoparticles(MNPs)have attracted extensive attention due to their unique physiochemical properties that make them highly applicable in various fields such as chemical sensing,energy storage,catalysis,medicine,and environmental engineering.Their physiochemical properties depend drastically on the MNP size and morphology,which are largely determined by their synthesis methods.Research on MNPs predominantly focused on coinage metals(Au,Ag and Cu),but in the last decade research on metals with a relatively high melting temperature such as Pd,Co,and Re has seen rapid increases,mainly driven by their potential applications as catalysts.This paper presents the recent advances on different synthesis techniques of Co,Pd,and Re nanoparticles,their resulting nanostructures,as well as existing and potential applications.