Design,Construction And Methanol Oxidation Properties Of Ti₃C₂T_x MXene Support Pd Catalyst

Environmental pollution and energy shortage are two major problems in the development of world today.The development of new types of energy storage and energy conversion devices has become an urgent need for social development.As a new type of energy conversion device,fuel cells have attracted more and more attention due to their advantages such as cleanliness,high efficiency,and sustainability.The main electrochemical reactions in fuel cells are the fuel oxidation reaction occurring at the anode and the oxygen reduction reaction occurring at the cathode.Thermodynamics and kinetics of the electrocatalytic reactions are important factors affecting the efficiency of the entire fuel cell device.Therefore,the preparation of high-efficiency electrocatalysts is of great significance to improve the rate of electrocatalytic reactions and promote the development of fuel cells.As a common industrial product,methanol is easier to produce and low in cost.Compared with hydrogen,liquid methanol is easier to be stored and transported,and has higher safety.Therefore,direct methanol fuel cells have great potential for commercial applications.However,the kinetic of methanol oxidation reaction in direct methanol fuel cell is slow due to the side-reactions.The high price and pore durability of catalyst are two main obstacles to achieve the development of DMFC.Therefore,it is of great significance to find more efficient,more stable and cheaper methanol oxidation reaction（MOR）electrocatalysts.Based on the above facts,this paper uses the new two-dimensional material MXene as the support material for traditional noble metal catalyst palladium（Pd）to achieve the MOR performance improvement by the inherent strong metal support interactions in Pd/Ti₃C₂T_x MXene catalyst.Spectral analyses and theoretical calculation of density functional theory（DFT）are used to explore the roles of MXene support on the MOR activity enhancement.The main research results of this paper are as follows:（1）In this paper,we prepared Pd/Ti₃C₂T_x MXene electrocatalyst by a simple method using Ti₃C₂T_x MXene as a support material.The method is simple,easy to implement,and repeatable.The as-prepared Pd/Ti₃C₂T_x MXene catalyst exhibits typical accordion-like architecture of MXene materials.（2）The morphology and chemical composition of the obtained Pd/Ti₃C₂T_x MXene catalyst were characterized by XRD,SEM,EDS and TEM.The characterization results proved that we successfully synthesized the Pd/Ti₃C₂T_x MXene catalyst material with Pd nanoparticles tightly supported on the MXene substrate.The EDS mapping images and quantitative results indicate a uniform distribution of Pd,Ti,and C elements.As shown in TEM images,uniformly dispersed Pd nanoparticles on MXene flakes exhibit a narrow size range within dozens of nanometers.（3）In the MOR performance test under alkaline conditions,the Pd/Ti₃C₂T_x MXene electrocatalyst exhibited a 60%improvement compared to the commercial Pd/C catalyst.Through subsequent spectral characterization and DFT calculations,we proved that the optimization of the catalyst’s electronic structure caused by the strong metal support interaction inherent in Pd/Ti₃C₂T_x MXene,the increase of Lewis basic sites,and the reduction in methanol adsorption energy were beneficial to improve MOR activity.