Improvement of performance of dye-sensitized solar cells based on electrodeposited-platinum counter electrode

Platinum nanoparticle was electrodeposited on FTO conducting glass substrate as counter electrode for application in dye-sensitized solar cells (DSSCs). Images of transmission electron microscope (TEM) and Scanning Electron Microscope (SEM) showed that platinum nanoparticle was with the mean size of 20-30 nm and was homogeneously distributed on the surface of the FTO conductive glass sheet. Using such a counter electrode, DSSC showed a 6.40% overall energy conversion efficiency under one sun illumination. It exhibited the same high-performance as the DSSC with a platinum counter electrode prepared by electroplating. Furthermore, the present preparation method for the platinum counter electrode has the advantage of low platinum loading and transparence.     

SFG study on potential-dependent structure of water at Pt electrode/electrolyte solution interface

Structure of water at Pt/electrolyte solution interface was investigated by sum frequency generation (SFG) spectroscopy. Two broad peaks were observed in OH stretching region at ca. 3200 cm⁻¹ and ca. 3400 cm⁻¹, which are known to be due to the symmetric OH stretching (υ₁) of tetrahedrally coordinated, i.e., strongly hydrogen bonded “ice-like” water, and the asymmetric OH stretching (υ₃) of water molecules in a more random arrangement, i.e., weakly hydrogen bonded “liquid-like” water, respectively. The SFG intensity strongly depended on electrode potential. Several possibilities are suggested for the potential dependence of the SFG intensity.     

Pt nanowires prepared via a polymer template method: Its promise toward high Pt-loaded electrocatalysts for methanol oxidation

Platinum nanowires were prepared via a template-synthesis method by electrodeposition of platinum within pores of a track-etched polycarbonate (PCTE) membrane, followed by chemical etching to separate the Pt nanowires from the polymer. The structure and morphology of the Pt nanowires were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM), revealing a polycrystalline phase with nanowire dimension up to 6 μm long and ca. 47 ± 9.8 nm of diameter. The unsupported Pt nanowires showed the better electrochemical mass activities over the methanol electro-oxidation than supported or unsupported Pt nanoparticles under the high Pt content-loaded conditions that is typically required for direct methanol fuel cells. This enhancement could be rationalized by its unique physicochemical and electrical properties arising from the inherent anisotropic one-dimensional (1D) nanostructure, such as charge transfer facilitation by reducing number of particle interfaces and more efficient use of Pt by alleviating fraction of embedded catalysts.     

Preparation and characterisation of platinum- and gold-coated copper, iron, cobalt and nickel deposits on glassy carbon substrates

Pt- and Au-coated Cu, Fe, Co and Ni deposits have been formed on glassy carbon (GC) substrates by electrodeposition of controlled amounts of the core metal onto the substrate and its subsequent partial replacement by Pt or Au upon immersion into a chloroplatinic or chlorolauric solution. This process resulted in a thin Pt or Au shell over the bimetallic particle as electrochemical evidence suggests, while indicative sputter-etch Auger Electron Spectroscopy points to the coexistence of the two metals in the particle core. SEM/EDS characterisation of the deposits revealed the existence of Pt(M) and Au(M) extensively agglomerated nanoparticles (M: Cu, Fe, Co, Ni). The surface electrochemistry of the deposits (hydrogen adsorption/desorption on Pt and oxide formation/stripping on Au) proved the complete coverage of the bimetallic particles by Pt or Au and allowed an estimate of their electroactive surface area. The study of hydrogen evolution at these deposits points to a modification of the electronic properties of the Pt and Au surface layers by the core metal (due to strain effects and/or ligand-electronic interactions) and further confirmed that these layers form a very thin outer shell.     

Platinum(VI) dihydroxo tetramesitylporphyrin; characterization and chemical reactivity

Tetramesitylporphyrin platinum(VI) dihydroxo complex, TMPPt(OH)₂ · 2 benzoate was synthesized by addition of two equivalent of meta-chloroperbenzoic acid molecules to the tetramesitylporphyrin platinum(II). This complex was characterized by X-ray diffraction and spectroscopic methods, and is capable to convert two molecules of triphenylphosphine to triphenylphosphine oxide.     

Preparation and electrocatalytic properties of tungsten carbide electrocatalysts

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Comparison of inward and outward grown Pt modified aluminide diffusion coatings on a Ni based single crystal superalloy

Two commercial Pt modified aluminide coatings (RT22 and MDC150L) on the same single crystal Ni-based superalloy (CMSX-4) were studied by: scanning electron microscopy; transmission electron microscopy; energy dispersive X-ray spectrometry; and gravimetry. The RT22 coating is an inward grown coating (high activity), while MDC150L is produced by outward growth (low activity). Samples were oxidised in still laboratory air at 1050 °C for various times up to 2000 h. It was found that the outward grown coating produced a slower growing oxide that was more spallation resistant. Several possible reasons for this were identified including: coating purity; coating surface topography; and ductile to brittle transition temperature. The microstructural differences between the two coatings in the as-coated condition were investigated and the development of their microstructure during heat treatment was described. A model for coating growth during heat treatment was proposed.     

铂钛不溶性阳极研制

主要研究了钛基镀铂工艺,确定了工艺中各种参数值,测定了铂钛不溶性阳极的各种性能.本工艺所得铂钛不溶性阳极耐腐蚀性强,与基体结合力好,镀层厚度2～5μm.     

表/界面调控策略在氢/氧反应电极中的研究进展

高效的非贵金属基电催化剂对于提升氢气析出反应（HER）、氧气析出反应（OER）、氧气还原反应（ORR）等电催化反应的整体效率、促进能源转换技术的发展及应用起着至关重要的作用。近年来,对现有的电催化剂进行表/界面调控以诱导其产生新的理化性质,从而提高催化活性的研究受到了广泛的关注。本文综述了近年来利用形貌尺寸调控、缺陷调控、杂原子掺杂、异质结结构等表/界面调控策略在设计非贵金属基电催化剂方面的研究进展,揭示了催化材料体系改性对优化和提升催化性能的关键特性。从催化剂制备、先进表征手段、理论计算、应用性评价等方面展望了非贵金属基电催化剂在实际应用中存在的挑战和未来的研究方向,为实现清洁能源的大规模应用提供参考。     

Enhanced activity and stability of Pt/C fuel cell anodes by the modification with ruthenium-oxide nanosheets

Ruthenium-oxide nanosheet (RuO₂ns) crystallites with thickness less than 1 nm were prepared via chemical exfoliation of a layered potassium ruthenate and deposited onto carbon supported platinum (Pt/C) as a potential co-catalyst for fuel cell anode catalysts. The electrocatalytic activity towards carbon monoxide and methanol oxidation was studied at various temperatures for different RuO₂ns loadings. An increase in electrocatalytic activity was evidenced at temperatures above 40 °C, while little enhancement in activity was observed at room temperature. The RuO₂ns modified Pt/C catalyst with composition of RuO₂:Pt = 0.5:1 (molar ratio) exhibited the highest methanol oxidation activity. CO-stripping voltammetry revealed that RuO₂ns promotes oxidation of adsorbed CO on Pt. In addition to the enhanced initial activity, the RuO₂ns modified Pt/C catalyst exhibited improved stability compared to pristine Pt/C against consecutive potential cycling tests.