Ionically crosslinked PBI/sulfonated polysulfone blend membranes are covalently crosslinked by thermal curing. The crosslinking unit is an aromatic sulfone group.

Au alloying into Pd can greatly improve the catalytic activity for FA dehydrogenation. Distinct PdAu surface ensembles are prepared and the Au alloying effects are revealed by experimental and theoretical examinations.

LaCrO3 perovskite and transition-metal (Co, Rh, Ir)-doped perovskite-based catalysts were fabricated using the Pechini method and applied to the dry reforming reaction of CH4 using CO2. One of the prepared perovskite-based catalysts, the LaCr0.95Ir0.05O3−δ catalyst, showed the highest CH4 conversion (81%) at 750 °C via the preactivation of the catalyst with H2 gas. It also showed highly stable catalytic activity for 72 h without coke formation on the catalyst surface. Through X-ray photoelectron spectroscopy and transmission electron microscopy analyses, it is confirmed that the improved catalytic activity of the LaCr0.95Ir0.05O3−δ perovskite-based catalyst was based on the exsolution of Ir nanoparticles on the catalyst surface, which catalyzes the cleavage of the C–H bond for CH4. Density functional theory calculations revealed that the exsolution of a dopant Ir in LaCr0.95Ir0.05O3−δ is more exothermic with/without an oxygen vacancy condition by 1.01 eV/0.43 eV, which suggests the agglomeration of Ir on the surface.

No abstract

Toward the development of sustainable and clean energy sources for the replacement of fossil fuels, strategies for constructing highly effective and durable trifunctional oxide electrocatalysts with zero emission carbon is a key step for boosting energy technologies through overall water splitting, regenerative fuel cells, and metal–air batteries. Here, two disordered ruthenate double-perovskites Ca2ScRuO6 (CSR) and CaSrScRuO6 (CSSR) were synthesized by the conventional high-temperature solid-state reaction method, and their trifunctional electrocatalytic behaviors for the oxygen reduction reaction (ORR) and oxygen and hydrogen evolution reactions (OER/HER) were investigated in alkaline medium (1 M KOH). The orthorhombic (space group Pbnm) crystal structures of both CSR and CSSR were refined from the neutron and laboratory X-ray powder diffraction data. The oxidation states of Ru cations in both compounds were shown to be predominantly Ru+5, confirmed by X-ray photoelectron spectroscopy studies. The as-prepared bulk perovskites showed excellent ORR performance with an onset potential of ∼0.89 V for CSR and 0.90 V vs reversible hydrogen electrode (RHE) for CSSR, respectively. In addition, both compounds showed significantly low overpotentials toward OER (353 and 323 mV) and HER (313 and 275 mV) at a current density of 10 mA cm–2, demonstrating them to be active trifunctional electrocatalysts. The substitution of an alkaline earth metal at the A-site introduces a synergistic effect of structural distortion and electronic properties of Ru+5 metal ions responsible for enhanced trifunctional electrocatalytic activities. Such trifunctional catalytic behaviors of CSR and CSSR materials can be further understood by density functional theory (DFT) calculations. The present finding not only provides insight into the catalytic activity of these materials but also presents an example of efficient trifunctional bulk-phase oxide electrocatalysts for practical applications.

The role of samarium (Sm) 4f states and Sm-perturbed O 2p states in determining the sulfur tolerance of Sm-doped CeO2 was elucidated by using the density functional theory (DFT) + U calculation. We find that the sulfur tolerance of Sm-doped CeO2 is closely related to the modification of O 2p states by the strong interaction between Sm 4f and O 2p states. In particular, the availability of unoccupied O 2p states near the Fermi level is responsible for enhancing the sulfur tolerance of Sm-doped CeO2 compared to the pure CeO2 by increasing the activity of the surface lattice oxygen toward sulfur adsorption, by weakening the interaction between Sm-O, and by increasing the migration tendency of the subsurface oxygen ion toward the surface.

A polymeric gas separation membrane utilizing polybenzimidazole based on 4,4 0 -(hexafluoroisopropylidene)bis(benzoic acid) was prepared. The synthesized membrane has an effective permeating area of 8.3 cm 2 and a thickness of 30 6 2 mm. Gas permeation properties of the membrane were determined using H 2 , CO 2 , CO, and N 2 at temperatures ranging from 248C to 2008C. The PBI-HFA membranes not only exhibited excellent H 2 permeability, but it also displayed superior gas separation performance particularly for H 2 /N 2 and H 2 /CO 2 . The permeation parameters for both permeability and selectivity [P H2 and a(H 2 /N 2 ); P H2 and a(H 2 / CO 2 )] obtained for the new material were found to be dependent on trans-membrane pressure difference as well as temperature, and were found to surpass those reported by Robeson in

No abstract