Preparation And Catalytic Application Of Pd-based Nanocatalysts

Ethanol offers a renewable and clean biofuel in fuel cells because it can be produced in large quantities from agricultural products,which makes direct ethanol fuel cell(DEFC)have a wide application prospect.Nowadays,the lack of active and durable anode catalysts has greatly limited the large-scale commercialization of DEFC.It is of vital significance to develop efficient anode catalysts for DEFC.So far,platinum(Pt)has been considered as one of the best catalysts and exclusively utilized in fuel cells,but they suffered from high cost,poor poison tolerance and scarcity of resources,which has limited the development and large-scale commercialization of fuel cells.Therefore,there is a hot topic to explore no-Pt catalysts.Compared with Pt-based catalysts,Palladium(Pd)has been prevalently studied and applied in many direct small molecules(methanol,formic acid,ethanol and etc.)fuel cells as anodic catalysts due to its excellent catalytic performance,more abundant resource and lower prices.Incorporating oxophilic metals into noble metal-based catalysts or preparing heterostructure catalysts represents an emerging strategy to improve the catalytic performance of electrocatalysts in fuel cells,but effects of the distance between the noble metal and oxophilic metal active sites on the catalytic performance have rarely been investigated.Here,we developed a new method to control the distance between Pd and Ni active sites in Pd-Ni-P ternary catalysts,which prompted the catalytic performance of ethanol oxidation reaction(EOR)and realized "surface atom engineering" of catalyst.We prepared a series of Pd-Ni-P nanocatalysts with different morphology.From Pd/Ni-P dumbbell heterodimers to Pd-Ni-P nanoparticles,the Pd cluster gradually dispersed in Ni-P,and the distance between Pd(active site of EOR)and Ni(active site of OHads)was shortened accordingly,which accelerated the mass transfer and reaction between different intermediates,enhancing the EOR activity of catalyst.In addition,the incorporating P can protect Ni from etching,endowing catalyst with better durability.The mass activity of obtained Pd-Ni-P ternary nanoparticles in ethanol oxidation reaction(EOR)is improved up to 4.95 A per mgPd in 1.0 M NaOH and 1.0 M C2H5OH solution,which is 6.88 times higher than commercial Pd/C.Combined with density functional theory(DFT)calculations analysis,we revealed a new strategy for high efficient anode catalysts of fuel cell.