Preparation And Electrocatalytic Performance Of Pd-based Catalysts

Direct liquid fuel cell(DLFC)has the advantages of high energy conversion efficiency,easy storage of fuel,and safe and reliable transportation,which has attracted widespread attention.However,the DLFC anode catalyst is generally Pt with a small reserve.Due to its high price,the cost of the battery is too high,which greatly limits the commercial development of DLFC.Therefore,it is particularly important to find a relatively cheap anode catalyst.Pd has a crystal structure similar to Pt,and Pd is relatively cheap,and has become an important research object in recent years.In order to realize the commercial application of DLFC,improving the catalytic efficiency of Pd and reducing the amount of Pd used have become a key part of the research.In this thesis,three-dimensional sponge-like Pd catalysts(S-Pd),two-dimensional PdCu nanosheets(PdCu NSs)and one-dimensional PdCu nanochains(PdCu NCs)with high catalytic performance were prepared by a one-step method.The main contents are as follows.(1)S-Pd was prepared by an easy-to-operate one-step method.Three-dimensional S-Pd is formed by interconnecting nano chains,which makes S-Pd excellent catalytic stability.S-Pd has a large number of mesopores and a heterogeneous structure,which exposes a large number of active sites.Compared with commercial Pd/C,the sample S-Pd has a larger active specific surface area(ECSA).Under acidic conditions,the oxidation peak current density of sample S-Pd to formic acid is 4.0 times that of commercial Pd/C;under alkaline conditions,the oxidation peak current density of sample S-Pd to ethanol and methanol are 2.2 times and 2.8 times that of commercial Pd/C.(2)PdCu NSs were prepared by a method similar to the above.The two-dimensional sheet structure of PdCu NSs gives it a large surface area.By adjusting the molar ratio of Pd and Cu,we found that compared with Pd/C,Pd₂Cu₁ NSs and Pd₄Cu₁NSs,Pd₃Cu₁ NSs has larger ECSA,and exhibits more excellent catalytic activity and stability for the oxidation of formic acid and ethanol.(3)The heterophase PdCu NCs were synthesized by a method similar to the above.The addition of Fe(NO₃)₃�9H₂O inhibits the structure guiding effect of CO molecules on the formation of nanosheets of PdCu alloy,thereby forming heterogeneous PdCu alloy nanochains.Compared with commercial Pd/C,the sample PdCu NCs has a larger ECSA.Under acidic conditions,the peak current density of formic acid oxidation by sample PdCu NCs is 3.6 times that of commercial Pd/C;under alkaline conditions,the peak current density of sample PdCu NCs for ethanol oxidation is 2.8 times that of commercial Pd/C.