Preparation Of PdCu Electrocatalyst For Formic Acid Oxidation By Cuprous Oxide Template Method And Study On Its Performance

Direct formic acid fuel cells（DFAFC）are considered to be one of the promising energy conversion devices,and palladium（Pd）-based nanocatalysts,although exhibiting better catalytic activity and anti-poisoning ability than platinum（Pt）-based nanocatalysts in formic acid oxidation reaction（FAOR）,but considering the high cost of Pd and its unremarkable stability,it is urgent to develop low-cost Pd-based catalysts with high activity and excellent stability.In view of the above problems,this paper adjusts the composition and morphology of the nanocatalysts.The specific content and results are as follows:In this dissertation,Cu₂O nanocubes with uniform particle size distribution are synthesized at room temperature by a facile method without adding organic solvents,which is used as templates for subsequent catalyst preparation and precursors of metallic Cu.（1）Pd-Cu₂O NCs（Nanocubes,NCs）are successfully prepared by a simple and efficient Galvanic replacement reaction（GRR）using self-made Cu₂O as a template.The activity of the catalyst in FAOR are investigated.The Pd-Cu₂O NCs with a Pd-Cu molar ratio of 0.3:1 has the largest ECSA among the same series of catalysts,which is 1.24times that of the Pd/C catalyst;meanwhile,its MA(676.14 m A mg_Pd^-1)is 1.51 times higher than that of the Pd/C catalyst(449.25 m A mg_Pd^-1),SA(2.78 m A cm_Pd^-2)is 1.22times higher than the Pd/C catalyst(2.28 m A cm_Pd^-2).Although the metal Pd content of the Pd-Cu₂O NCs/0.3:1 catalyst is lower than that of the Pd/C catalyst,its enhanced catalytic activity can be attributed to the adequate exposure of active sites resulting from the uniform dispersion of Pd on the Cu₂O surface and the proper Pd content.（2）Pd-Cu NPs（Nanoparticles,NPs）catalysts are prepared by hydrothermal method,and the molar ratio of Pd-Cu was controlled by changing the concentration of Pd Cl₂aqueous solution.Then,the catalytic activities of catalysts with different Pd contents in FAOR are investigated.The MA(743.1 m A mg_Pd^-1)and SA(3.07 m A cm_Pd^-2)of the Pd-Cu NPs/2:1 catalyst with a Pd-Cu molar ratio of 2:1 have maximum values,which are 1.65 and 1.35 times for the Pd/C catalyst,respectively.Due to the synergistic effect between the formed Pd Cu alloys,the electron cloud distribution on the Pd surface was changed,which weakened the adsorption capacity of the catalyst for small molecules such as CO during the FAOR process,resulting in the release of active sites,which contributed to the improvement of the FAOR rate.（3）The catalyst is obtained by calcining the homemade Pd-Cu₂O NCs catalyst prepared in H₂/Ar atmosphere,and the product after heat treatment is Pd-Cu ANSs（Alloy Nanospheres,ANSs）.To explore the catalytic activity of catalysts with different Pd-molar ratios of Cu in FAOR,where the Pd-Cu ANSs/0.3:1 catalyst exhibited the highest catalytic activity among the same series of catalysts,its MA(1569.48 m A mg_Pd^-1)is 3.49 times higher than that of the Pd/C catalyst,and its SA(6.11m A cm_Pd^-2)is still the largest,which is 2.68 times that of the Pd/C catalyst.The enhanced catalyst activity can be attributed to its special structure and the uniform dispersion of Pd and Cu throughout the nanospheres,which makes the alloying effect between Pd Cu fully exerted,which leads to the change of the electronic structure of Pd,which accelerates the oxidation of CO and more active sites are released in a short time.