Controble Synthesis And Electro Catalytic Properties Of Platinum-Palladium Bimetallic Nanostructures Supported On Reduced Graphene Oxide

Noble metal nanomaterials have unique optical, electrical, thermal and chemical activity, catalysis and superconducting features. However, binary noble metal nanomaterials with complex structure have the characteristics of nanoparticles and internal structure of coupling of electrons and lattice strain effect, showing more excellent photoelectric catalysis performance in comparison with single noble metal nanomaterials. Graphene has good optical properties, large specific surface area, good thermal conductivity and electrical conductivity, becoming a kind of novel catalyst support material. The binary noble metal/graphene nanocomposites not only have related properties of the two kinds of material, but also show some novel features through the synergistic effect. At present, widely research and application have been made in catalysis, sensing, biomedical diagnosis and therapy, energy storage and conversion, and so on. Thus, developing new synthetic binary metal/graphene nanocomposites are of great significance. This paper mainly studied five novel synthetic methods of platinum-palladium/graphene nanocomposites with different morphologies, and studied the morphology, composition, growth mechanism, and their applications in electrocatalysis in detail. Specific content as follows:1. Facile synthesis of hierarchical dendritic PtPd nanogarlands supported on reduced graphene oxide with enhanced electrocatalytic propertiesA simple and facile method was developed for one-pot preparation of hierarchical dendritic PtPd nanogarlands supported on reduced graphene oxide (PtPd/RGO) at room temperature. It was found that octylphenoxypolye thoxyethanol (NP-40) as a soft template and its amount are critical to the formation of the PtPd garlands. The nanocomposites were applied to methanol and ethanol oxidation with significantly enhanced electrocatalytic activity and better stability in alkaline media.2. Branched platinum-on-palladium bimetallic heteronanostructures supported on reduced graphene oxide for highly efficient oxygen reduction reactionA facile one-pot wet-chemical approach was developed for synthesis of high-quality three-dimensional platinum-on-palladium (Pt-on-Pd) bimetallic nanodendrites supported on reduced graphene oxide (RGO), where NP-40 acted as a growth-directing agent under mild conditions. The nanocomposites exhibited enhanced oxygen reduction reaction activity (onset potential of 0.05 V, half-wave potential of-0.15 V, electron transfer number>3.99) and better stability in alkaline media.3. Facile synthesis of PdPt@Pt nanorings supported on reduced graphene oxide with enhanced electrocatalytic propertiesA facile one-pot wet-chemical method was developed for self-assembly of PdPt@Pt nanorings via in situ reduction of PdCl42- and PtCl62- at room temperature, which were simultaneously dispersed on reduced graphene oxide (PdPt@Pt/RGO). Hexadecylpyridinium chloride (HDPC) was demonstrated as a shape-directing agent during the reaction process. The as-prepared PdPt@Pt/RGO exhibited the enhanced electrocatalytic activity for oxygen reduction and ethanol oxidation in acid media, compared with PtPd/RGO, Pt/RGO, Pd/RGO, Pt black, and Pt/C catalysts.4. Facile synthesis of porous Pt-Pd nanospheres supported on reduced graphene oxide nanosheets for enhanced methanol electrooxidationA simple, facile, and effective wet-chemical strategy was developed in the synthesis of uniform porous Pt-Pd nanospheres (Pt-Pd NSs) supported on reduced graphene oxide nanosheets (RGO) under ambient temperature, where NP-40 was used as a soft template and formic acid worked as a reducing agent. The as-prepared nanocomposites displayed enhanced electrocatalytic activity toward methanol oxidation, compared with Pd/C and Pt/C catalysts.5. Simple synthesis of hollow Pt-Pd nanospheres supported on reduced graphene oxide for enhanced methanol electrooxidationA simple, facile, and one-pot wet-chemical route was developed for large-scale synthesis of reduced graphene oxide nanosheets (RGO) supporting Pt-Pd hollow nanospheres (Pt-Pd HNSs) without any additives, seed, template, or special apparatus. The as-prepared RGO/Pt-Pd HNSs displayed excellent electrocatalytic activity toward methanol oxidation in alkaline media, compared with Pt black and Pd black catalysts.