ABSTRACT
Finding out robust active and sustainable catalyst towards alcohol electro-oxidation reaction is major challenges for large-scale commercialization of direct alcohol fuel cells. Herein, a robust Pt nanowires (NWs)/Ti0.7W0.3O2 electrocatalyst, as the coherency of using non-carbon catalyst support and controlling the morphology and structure of the Pt nanocatalyst, was fabricated via an effortless chemical reduction reaction approach at room temperature without using surfactant/stabilizers or template to assemble an anodic electrocatalyst towards methanol electro-oxidation reaction (MOR) and ethanol electro-oxidation reaction (EOR). These observational results demonstrated that the Pt NWs/Ti0.7W0.3O2 electrocatalyst is an intriguing anodic electrocatalyst, which can alter the state-of-the-art Pt NPs/C catalyst. Compared with the conventional Pt NPs/C electrocatalyst, the Pt NWs/Ti0.7W0.3O2 electrocatalyst exhibited the lower onset potential (~0.1 V for MOR and ~0.2 for EOR), higher mass activity (~355.29 mA/mgPt for MOR and ~325.01 mA/mgPt for EOR) and much greater durability. The outperformance of the Pt NWs/Ti0.7W0.3O2 electrocatalyst is ascribable to the merits of the anisotropic one-dimensional Pt nanostructure and the mesoporous Ti0.7W0.3O2 support along with the synergistic effects between the Ti0.7W0.3O2 support and the Pt nanocatalyst. Furthermore, this approach may provide a promising catalytic platform for fuel cell technology and a variety of applications.
ABSTRACT
In this work, mesoporous Ti0.7W0.3O2 materials with high conductivity and surface area as promising catalyst support for Pt in Proton-Exchange Membrane Fuel Cells (PEMFCs) were synthesized via a single-step solvothermal process at low-temperature without using any surfactants or stabilizers. The characterizations of material are measured via XRD, TEM, SEM-EDS, and BET as well as electronic conductivity measurement. As a result, Ti0.7W0.3O2 formed a homogenous solid solution with mesoporous anatase-TiO2 structure and uniformly spherical nanoparticles morphology of about ~10 nm diameter, together with a high electrical conductivity of 0.022 S/cm compared to that of undoped-TiO2 (1.37×10-7 S/cm), which implied that tungsten (VI) ions was successfully doped into anatase-TiO2 lattices. The N2 adsorption/desorption isotherms indicated that Ti0.7W0.3O2 is being mesoporous structure with high surface area up to ~202 m²/g, which is nearly similar to that of the commercial Vulcan XC72 (~232 m²/g). The Pt nanoparticles was easily anchored onto Ti0.7W0.3O2 surface by the chemical reduction process using NaBH4 as a reducing agent. The spherical Pt nanoparticles of ~9 nm in diameter were deposited uniformly on the mesoporous support. These results suggested that mesoporous Ti0.7W0.3O2 materials synthesized are promising catalyst supports to replace carbon-based supports for Proton-exchange membrane fuel cells.
ABSTRACT
The present study focused on the application of response surface methodology to optimize the fabrication of activated carbon (AC) from sugarcane bagasse for adsorption of Cu2+ ion. The AC was synthesized via chemical activation with ZnCl2 as the activating agent. The central composite design based experiments were performed to assess the individual and interactive effect of influential parameters, including activation temperature, ZnCl2 impregnation ratio and activation time on the AC yield and removal of Cu2+ ion from the aqueous environment. The statistically significant, well-fitting quadratic regression models were successfully developed as confirmed by high F- and low P-values (<0.0001), high correlation coefficients and lack-of-fit tests. Accordingly, the optimum AC yield and removal efficiency of Cu2+ were predicted, respectively, as 48.8% and 92.7% which were approximate to the actual values. By applying the predicted optimal parameters, the AC shows a surprisingly high surface area of around 1,500 m2/g accompanied by large pore volume and narrow micropore size at low fabrication temperature.
Subject(s)
Cellulose/chemistry , Charcoal/chemistry , Chlorides/chemistry , Copper/chemistry , Saccharum/chemistry , Water Pollutants, Chemical/chemistry , Zinc Compounds/chemistry , Adsorption , TemperatureABSTRACT
The slow rate of the oxygen reduction reaction (ORR) and the instability of Pt-based catalysts are two of the most important issues that must be solved in order to make proton exchange membrane fuel cells (PEMFCs) a reality. Additionally, the serious carbon corrosion on the cathode side is a critical problem with respect to the durability of catalyst that limits its wide application. Here, we present a new approach by exploring robust noncarbon Ti(0.7)Mo(0.3)O(2) used as a novel functionalized cocatalytic support for Pt. This approach is based on the novel nanostructure Ti(0.7)Mo(0.3)O(2) support with "electronic transfer mechanism" from Ti(0.7)Mo(0.3)O(2) to Pt that can modify the surface electronic structure of Pt, owing to a shift in the d-band center of the surface Pt atoms. Furthermore, another benefit of Ti(0.7)Mo(0.3)O(2) is the extremely high stability of Pt/Ti(0.7)Mo(0.3)O(2) during potential cycling, which is attributable to the strong metal/support interaction (SMSI) between Pt and Ti(0.7)Mo(0.3)O(2). This also enhances the inherent structural and chemical stability and the corrosion resistance of the TiO(2)-based oxide in acidic and oxidative environments. We also demonstrate that the ORR current densities generated using cocatalytic Pt/Ti(0.7)Mo(0.3)O(2) are respectively ~7- and 2.6-fold higher than those of commercial Pt/C and PtCo/C catalysts with the same Pt loading. This new approach opens a reliable path to the discovery advanced concept in designing new catalysts that can replace the traditional catalytic structure and motivate further research in the field.
