Controlled Synthesis Of Palladium Based Bimetallic Nanomaterials And Their Electrocatalysis Research

With the world’s concerning over environmental pollution and the rapid depletion of conventional energy sources, the clean energy is in growing demand for human. Fuel cells have been receiving considerable attention, due to its high efficiency, low noisy, and no pollution. The electrocatalysts are the key matter to influence the efficiency and lifespan of fuel cells. As known, the catalytic performance of nanomaterials can be tailored by controlling the size, morphology as well as composition. As a result, it’s highly meaningful to exploit facile and low-cost synthesis strategies to obtain catalysts with enhanced catalytic property, stability and anti-poisoning activity.Herein, this paper developed five Pd-based nanomaterials based on the wet-chemical method and solvothermal strategies. Meanwhile, we profoundly studied their composition, structure, formation mechanism and catalytic performance for catalyzing the anodic and cathodic reactions in fuel cells. Specific experiments include the following five parts:(1) Facile synthesis of three-dimensional Pt-Pd alloyed multipods with enhanced electrocatalytic activity and stability for ethylene glycol oxidationA facile one-pot solvothermal method was developed for fabrication of well-defined three-dimensional highly branched multipods Pt-Pd alloyed nanostructures, using ethylene glycol as a solvent and a reducing agent, along with N-methylimidazole as a structure-directing agent, without any seed, template, or surfactant. The as-prepared nanocrystals exhibited larger electrochemically active surface area, improved electrocatalytic activity and superior stability for ethylene glycol oxidation reaction in alkaline media, compared with commercial Pt black and Pd black.(2) Facile synthesis of Pt-Pd nanodendrites and their superior electrocatalytic activityHighly porous Pt-Pd nanodendrites were synthesized by a facile one-pot and environmentally friendly wet-chemical method by using poly(vinylpyrrolidone) and. urea as the co-stabilizing and co-structure-directing agents, without any seed, template, or organic solvent. The physical characterization and formation mechanism of the Pt-Pd nanodendrites were investigated in detail. The as-prepared Pt-Pd nanocrystals had larger active surface area, superior catalytic activity, and better stability toward the electrooxidation of methanol and ethylene glycol, compared with the commercial Pt black and Pd black.(3) Simple synthesis of Pt-Pd nanoflowers on reduced graphene and their enhanced electrocatalytic activity for oxygen reduction reactionA facile one-pot wet-chemical method was developed for preparation of reduced graphene nanosheets supported Pt-Pd nanoflowers (Pt-Pd NFs/RGOs) using hydrazine hydrate as a reducing agent. The Pt-Pd NFs/RGOs owned higher catalytic activity and better durability for oxygen reduction reaction in acidic media, compared with the commercial Pt-C.(4) One-pot synthesis of monodisperse palladium-copper nanocrystals supported on reduced graphene nanosheets with improved catalytic activity and methanol tolerance for oxygen reduction reactionMonodisperse bimetallic alloyed palladium-copper nanocrystals are uniformly supported on reduced graphene nanosheets by a one-pot solvothermal strategy. The as-prepared nanocomposites possessed the enlarged electrochemically active surface area, and displayed the improved electrocatalytic performance and high methanol-tolerance ability for oxygen reduction reaction in alkaline media, compared with commercial Pd black and reduced graphene.(5) Monodisperse Au-Pd nanoparticles supported on reduced graphene with enhanced electrocatalytic activity towards oxygen reduction reactionA facile, straightforward, and efficient solvothermal strategy was developed for preparation of well-defined monodisperse Au-Pd nanoparticles uniformly supported on reduced graphene nanosheets. The as-prepared nanocomposites displayed enhanced electrocatalytical ability, better stability, and good methanol tolerance towards oxygen reduction reaction in alkaline media, compared with commercial Pd black.