Preparation Of Palladium-based Nanocatalysts And Their Electrocatalytic Performance

Fuel cell is an emerging energy conversion device that directly converts chemical energy from fuel(including chemical energy from various renewable energy sources)into electrical energy.The advantages of fuel cells,such as low environmental pollution,high energy conversion rate,wide range of fuel sources,and low operating temperature,making it a promising prospect for commercial application.The research of catalysts with excellent electrocatalytic activity and low cost is important to promote the commercialization of fuel cells.Pd-based catalysts have become a hot research topic in the field of fuel cell catalysts because of their lower cost compared to Pt-based noble metal catalysts.In this thesis,noble metal-based nanocatalysts with special morphological structures were successfully prepared by alloying noble metal Pd with non-metals(P,H)or common transition metals(Co)by certain synthetic methods,and we investigated the synergistic effects of their structures and compositions.The specific work capacity is divided into three main areas:1.Various porous Pd Co P nanoparticle catalysts with different elemental ratios were prepared by a one-step method and using triphenylphosphine as the phosphine source.The growth mechanism was also investigated,and it was confirmed that the introduction of carbon monoxide is the key to the successful preparation of porous structure,while the presence of carbon monoxide accelerates the decomposition of Co and P in the precursors.The growth mechanism suggests that the morphological evolution process of nanosheets to nanoparticles with holes occurs as the reaction temperature increases.The ethanol oxidation performance of porous Pd Co P nanocatalysts was tested under alkaline conditions.The doping of phosphine can effectively modulate the electronic structure of Pd Co P and enhance its electrical conductivity,and this high catalytic activity is the result of the synergistic effect of morphological structure and constituent components.2.Pd H catalysts with reticulated morphological structures were synthesized by a simple one-pot method.XRD showed that the prepared Pd H was in ?-phase.The electrocatalytic oxidation performance of the reticulated Pd H catalyst for formic acid was also tested under acidic conditions,and the mass activity was improved by about2.2 times compared with that of commercial Pd/C.Such an enhancement in performance may be due to the change in electronic structure after the combination of Pd with H.3.Pd P nanowires with holes were prepared by a one-step method using triphenylphosphine as the phosphine source in a co-reduction system of carbon monoxide and oleylamine.The electrocatalytic oxidation performance of porous Pd P nanowires for ethanol was tested under alkaline conditions,and the P-doped Pd P nanowires with holes exhibited superior electrocatalytic activity and stability compared with commercial Pd/C.