Preparation And Performance Investigation Of Pd-based Nano-catalysts For Formic Acid Dehydrogenation And Oxidation Of Ethanol

Fuel cells,due to their high energy conversion rate,low noise,ease of storage and transportation,and lack of pollution,are significant in optimizing energy structure.Among these,direct hydrogen fuel cells and direct ethanol fuel cells have garnered increasing attention due to their broad fuel sources and environmental benefits.Nonetheless,the low density of hydrogen fuel poses challenges for storage and transportation,while the sluggish anode reaction kinetics of ethanol fuel cells remain a bottleneck issue that hinders their progress.Hence,the development of efficient catalysts is crucial yet challenging to enhance the hydrogen production efficiency of hydrogen storage materials and the anode oxidation reaction efficiency of direct ethanol fuel cells.This study aims to design a range of palladium-based catalysts and investigate their hydrogen production from formic acid（FA）and ethanol oxidation properties.1.The process of carbonization was employed on agricultural waste rice straw,resulting in the production of rice straw modified carbon（RSPC）through KOH activation.Subsequently,Pd Au nanoparticles（NPs）were deposited onto amino-functionalized RSPC support（RSPNC）via a wet chemical method to create the Pd_0.7Au_0.3/RSPNC catalyst.This catalyst exhibited exceptional catalytic performance in the hydrogen production from FA and ethanol oxidation.（1）Under the experimental conditions of 323 K and in the absence of any additives,the Pd_0.7Au_0.3/RSPNC catalyst exhibits complete selectivity towards H₂ and does not generate any toxic CO gas.The catalyst’s initial conversion frequency（TOF）is 6794.3 mol H₂ mol catalyst^-1h^-1,indicating superior catalytic activity compared to most reported palladium-based heterogeneous catalysts.（2）In the context of electrocatalytic ethanol oxidation,the Pd_0.7Au_0.3/RSPNC catalyst demonstrates a mass activity of 6.281 A mg _Pd^-1 and a specific activity of 7.836 m A cm^-2 at room temperature,surpassing that of commercial Pd/C.These results highlight the exceptional catalytic performance of the Pd_0.7Au_0.3/RSPNC catalyst.The superior catalytic performance of the catalyst can be ascribed to the pore architecture and amino functionalities of RSPNC,which facilitate the deposition of Pd Au NPs with a highly refined size and improved dispersion.This,in turn,enhances the density of active sites and augments the interfacial contact between the catalyst and reactants,thereby promoting the catalytic activity.2.Calcination of potassium citrate at high temperature resulted in the production of Carbon nanosheets（CNSs）,which were subsequently utilized as a support for the successful synthesis of Pd Au NPs catalyst(Pd_0.7Au_0.3/CNSs)through an in-situ reduction method.The electrocatalytic ethanol oxidation reaction was conducted at room temperature,and the Pd_0.7Au_0.3/CNSs catalyst exhibited a mass activity of 1.719 A mg _Pd^-1 and a specific activity of 3.676 m A cm^-2,both of which were superior to those of commercial Pd/C.A sequence of investigations revealed that the catalyst exhibited favorable catalytic activity as a result of the in-situ reduction technique,which preserved the multi-stage configuration of the CNSs carrier and enhanced the dispersion of Pd Au NPs during the reaction,thereby promoting the enhancement of catalytic reaction efficiency.