Search

The performance of cobalt supported on mesoporous alumina (MA) under the influence of reaction temperature (923 K–1073 K) and reactant partial pressure (10 kPa–40 kPa) for CO 2 –CH 4 reforming was executed by using a tubular fixed-bed reactor. 10%Co/MA exhibited great catalytic performance (X C H 4 = 70.9 % , X C O 2 = 71.7 % and D a = 1.3 %), credited to the well dispersion of Co within pore MA, strong metal-support interaction, and MA confinement ability. Based on Langmuir-Hinshelwood kinetic analysis, the dissociative adsorption of both reactants on a single Co active site was selected for this study. The lower value of activation energy (28.9 kJ mol−1) suggested that Co particles were finely scattered on the MA surface. Regardless of carbon types, the amount of coke accumulated on the spent 10%Co/MA within 8 h of CO 2 –CH 4 reforming was inhibited due to fine Co distribution inside MA structure, as well as lessened with the raise of reforming temperature from 923 to 1073 K due to improvement in reverse Boudouard reaction. [Display omitted] • Co/MA exhibited excellent activity and coke resistance for CO 2 –CH 4 reforming. • Excellent activity of Co/MA was due to strong Co-MA interaction and well Co dispersion. • Kinetic analysis suggested the dissociative adsorption of reactants on a single Co active site. • Well distribution of Co particles on Co/MA lowered the activation energy of reaction. [ABSTRACT FROM AUTHOR]

The mesoporous gamma-alumina (γ-Al 2 O 3) synthesized via evaporation-induced self-assembly method (EISA) using inorganic salt, Al(NO 3) 3 ·9H 2 O precursor and water-ethanol solvent mixture was implemented as a support for Co catalyst in methane dry reforming at 973–1073 K under 1 atm. The γ-Al 2 O 3 support possessed filament-shaped morphology with surface area of 173.4 m2 g−1 and cobalt nanoparticles were successfully dispersed on support with small crystallite size of 7.8 nm. The stability of 10%Co/Al 2 O 3 was evident for CH 4 and CO 2 conversions at 1023 and 1073 K. CH 4 conversion could reach to 76.2% while 81.6% was observed for CO 2 conversion at 1073 K. Although graphitic and amorphous carbons were unavoidably formed on used catalyst, 10%Co/Al 2 O 3 exhibited an outstanding performance comparable to noble metals with the desired ratio of H 2 /CO for downstream Fischer-Tropsch process. [Display omitted] • Filament-shaped Al 2 O 3 was synthesized by evaporation-induced self-assembly method. • 10%Co/Al 2 O 3 exhibited a comparable activity to noble catalysts. • H 2 /CO ratio from methane dry reforming was obtained from 0.6 to 0.9. [ABSTRACT FROM AUTHOR]

3%Ce- and 3%La-promoted 10%Cu/Al 2 O 3 catalysts were synthesized via a sequential incipient wetness impregnation approach and implemented for ethanol CO 2 reforming (ECR) at 948–1023 K and stoichiometric feed ratio. CeO 2 and La 2 O 3 promoters reduced CuO crystallite size from 32.4 to 27.4 nm due to diluting impact and enhanced the degree of reduction of CuO → Cu0. Irrespective of reaction temperature, 3%La–10%Cu/Al 2 O 3 exhibited the highest reactant conversions, H 2 and CO yields followed by 3%Ce–10%Cu/Al 2 O 3 and 10%Cu/Al 2 O 3. The greatest C 2 H 5 OH and CO 2 conversions of 87.6% and 55.1%, respectively were observed on 3%La–10%Cu/Al 2 O 3 at 1023 K whereas for all catalysts, H 2 /CO ratios varying from 1.46 to 1.91 were preferred as feedstocks for Fischer-Tropsch synthesis. Activation energy for C 2 H 5 OH consumption was also reduced with promoter addition from 53.29 to 47.05 kJ mol−1. The thorough CuO → Cu0 reduction by H 2 activation was evident and the Cu0 active phase was resistant to re-oxidation during ECR for all samples. Promoters addition reduced considerably the total carbon deposition from 40.04% to 27.55% and greatly suppressed non-active graphite formation from 26.94% to 4.20% because of their basic character and cycling redox enhancement. Image 1 • 3%La–10%Cu/Al 2 O 3 exhibited high C 2 H 5 OH (87.6%) and CO 2 (55.1%) conversions. • Promoter addition reduced C 2 H 5 OH activation energy from 53.29 to 47.05 kJ mol−1. • CeO 2 and La 2 O 3 hindered carbon deposition from 40.04% to 27.55%. [ABSTRACT FROM AUTHOR]

The novel nanostructured Ti 0.9 Ir 0.1 O 2 acting as a potential catalyst support for Pt in fuel cell applications was easily synthesized by means of a facile and simple low-temperature hydrothermal process without using any surfactants and further heat treatment. Interestingly, even in low iridium doping concentration, the Ti 0.9 Ir 0.1 O 2 support possessed the high electronic conductivity of 0.016 S/cm, which was ∼105 times as high as pure TiO 2 (4.15 × 10−7 S/cm), suggesting the efficient doping of iridium into TiO 2 lattice. Furthermore, the modified chemical reduction route utilized to prepare the 20 wt % Pt/Ti 0.9 Ir 0.1 O 2 electrocatalyst exhibited the good anchoring and uniform distribution of Pt nanoparticles (NPs) (∼3 nm) over Ti 0.9 Ir 0.1 O 2 surface and thus eventually resulted in the high electrochemical surface area (∼85.08 m2/gPt) compared to that of the commercial 20 wt % Pt/C (E-TEK) catalyst (∼69.21 m2/gPt). The cyclic voltammetry results in the methanol media revealed that the 20 wt % Pt/Ti 0.9 Ir 0.1 O 2 displayed the superior electrocatalytic activity compared to the 20 wt % Pt/C (E-TEK) catalyst towards the methanol electro-oxidation. For instance, the 20 wt % Pt/Ti 0.9 Ir 0.1 O 2 catalyst possessed the higher oxidation current density (∼28.8 mA/cm2), the lower onset potential (∼0.12 V) and the higher I f /I b ratio in comparison with the commercial 20 wt % Pt/C (E-TEK) catalysts. It is worth noting that the chronoamperometry results also indicated that the 20 wt % Pt/Ti 0.9 Ir 0.1 O 2 exhibited higher durability than the commercial 20 wt % Pt/C (E-TEK) catalyst. Beside introducing novel Ti 0.9 Ir 0.1 O 2 material, these results also offer a pathway of exploring the low dopants content of Ti x Ir 1-x O 2 material to serve as a good catalyst support for many fuel cell applications. • A facile green synthetic route for the preparation of the novel Ti 0.9 Ir 0.1 O 2. • The Ti 0.9 Ir 0.1 O 2 possessed high electronic conductivity with the low doping concentration. • Pt/Ti 0.9 Ir 0.1 O 2 has low onset potential for methanol oxidation reaction. • Pt/Ti 0.9 Ir 0.1 O 2 demonstrates high activity and durability for methanol oxidation. [ABSTRACT FROM AUTHOR]