Rheological and physical characterization of PEDOT: PSS/graphene oxide nanocomposites for perovskite solar cells

In this work, the influence of graphene oxide (GO) doped Poly(3,4 ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) thin nanocomposite on an indium–tin-oxide (ITO) anode, as hole transport layer (HTL) in perovskite solar cells, was investigated. Different concentrations of GO were added into the PEDOT:PSS in order to enhance its conductivity. In particular, the influence of GO content on the rheological and thermal properties of Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/ GO nanocomposites was initially examined. The GO filler was prepared by using modified Hummers method and dispersed into PEDOT:PSS in different quantity (ranging from 0.05 to 0.25%wt/wt). The obtained nanocomposite solutions were analyzed by rheological characterizations in order to evaluate the influence of the GO filler on the viscosity of the PEDOT:PSS matrix. The wettability of solutions was evaluated by Contact Angle (CA) measurements. The quality of GO dispersion into the polymer matrix was studied using Scanning electron microscopy (SEM) and X-ray diffraction (XRD). Thermal characterizations (DSC and TGA) were, finally, applied on nanocomposite films in order to evaluate thermal stability of the films as well as to indirectly comprehend the GO influence on PEDOT:PSS-water link

Facile One-Step Synthesis of Three-Dimensional Pd–Ag Bimetallic Alloy Networks and Their Electrocatalytic Activity toward Ethanol Oxidation

The three-dimensional palladium networks and palladium–silver bimetallic alloy networks were synthesized at room temperature on a large scale using a rapid and simple strategy. The results revealed that the morphology of the networks is not affected by the composition. We demonstrated that the as-prepared unsupported networks exhibited excellent electrochemical activity and stability toward ethanol oxidation reaction in alkaline media due to the formation of palladium–silver alloys as well as the porous nanostructures. The results indicate that the well-defined three-dimensional palladium–silver bimetallic alloy networks are promising catalysts for fuel cells

Enhanced Electrocatalytic Activities of PtCuCoNi Three-Dimensional Nanoporous Quaternary Alloys for Oxygen Reduction and Methanol Oxidation Reactions

Control of morphology and composition could precisely and efficiently alter the catalytic properties of Pt-based materials, improving the electrocatalytic activity and durability. Here we proposed a rapid, controllable synthesis of three-dimensional PtCuCoNi quaternary alloys with low Pt-group metal, which were directly synthesized by reducing metal precursors in aqueous solution. The resultant quaternary alloys show excellent oxygen reduction and methanol oxidation reaction activities in acid solution. By rational tuning of the composition of PtCuCoNi alloys, they achieved a mass activity of 0.72 A/mg_Pt on the basis of Pt mass for oxygen reduction reaction. Moreover, the durability is also higher than that of commercial Pt/C catalyst. These PtCuCoNi quaternary alloys characterized by three-dimensional porous nanostructures hold attractive promise as substitutes for carbon-supported Pt catalysts with improved activity and stability

Porous graphene doped with Fe/N/S and incorporating Fe\u3csub\u3e3\u3c/sub\u3eO\u3csub\u3e4\u3c/sub\u3e nanoparticles for efficient oxygen reduction

The rational construction of a carbon base with a porous structure and incorporating effective dopants is an intriguing and challenging strategy used to develop advanced electrocatalysts for the oxygen reduction reaction (ORR). Herein, we synthesize a novel, efficient electrocatalyst comprised of three-dimensional (3D) porous graphene doped with Fe/N/S and incorporating Fe3O4 nanoparticles (Fe3O4/FeNSG). We use a melamine formaldehyde resin which plays the dual-functional roles of a soft template and a nitrogen-abundant source. The rational design of the Fe3O4/FeNSG-3 with its 3D porous architecture, abundant active sites (Fe–N–C, Fe3O4, pyridinic N, C–S–C, et al.), and large surface area (530.5 m2 g−1) makes it an efficient electrocatalyst towards ORR. The Fe3O4/FeNSG-3 catalyst shows a positive ORR onset potential (0.951 V) and half-wave potential (0.810 V), comparable to those of the commercial Pt/C electrocatalyst in alkaline media. Furthermore, the catalyst exhibits a four-electron transfer pathway, superior methanol tolerance and good stability. This work paves the way for preparing low-cost, active, stable, non-Pt group metal catalysts through regulating the active catalytic sites on 3D graphene with a porous architecture

Kinetically Controlled Synthesis of Pt-Based One-Dimensional Hierarchically Porous Nanostructures with Large Mesopores as Highly Efficient ORR Catalysts

Rational design and construction of Pt-based porous nanostructures with large mesopores have triggered significant considerations because of their high surface area and more efficient mass transport. Hydrochloric acid-induced kinetically controlled reduction of metal precursors in the presence of soft template F-127 and hard template tellurium nanowires has been successfully demonstrated to construct one-dimensional hierarchical porous PtCu alloy nanostructures with large mesopores. Moreover, the electrochemical experiments demonstrated that the PtCu hierarchically porous nanostructures synthesized under optimized conditions exhibit enhanced electrocatalytic performance for oxygen reduction reaction in acid media

Ultrasonic-assisted synthesis of Pd-Pt/carbon nanotubes nanocomposites for enhanced electro-oxidation of ethanol and methanol in alkaline medium

Herein, a facile ultrasonic-assisted strategy was proposed to fabricate the Pd-Pt alloy/multi-walled carbon nanotubes (Pd-Pt/CNTs) nanocomposites. A good number of Pd-Pt alloy nanoparticles with an average of 3.4 ± 0.5 nm were supported on sidewalls of CNTs with uniform distribution. The composition of the Pd-Pt/CNTs nanocomposites could also be easily controlled, which provided a possible approach for the preparation of other architectures with anticipated properties. The Pd-Pt/CNTs nanocomposites were extensively studied by electron microscopy, induced coupled plasma atomic emission spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, and applied for the ethanol and methanol electro-oxidation reaction in alkaline medium. The electrochemical results indicated that the nanocomposites had better electrocatalytic activities and stabilities, showing promising applications for fuel cells