Rationally designing active and durable catalysts for the oxygen evolution reaction (OER) is of primary importance in water splitting. Perovskite oxides (ABO3) with versatile structures and multiple physicochemical properties have triggered considerable interest in the OER. The leaching of A site cations can create nanostructures and amorphous motifs on the perovskite matrix, thus facilitating the OER process. However, selectively dissolving A site cations and simultaneously obtaining more active amorphous motifs derived from the B site cations remains a great challenge. Herein, a top‐down strategy is proposed to transform bulk crystalline perovskite (LaNiO3) into a nanostructured amorphous hydroxide by FeCl3 post‐treatment, resulting in an extremely low overpotential of 189 mV at 10 mA cm−2. The top‐down‐constructed amorphous catalyst with a large surface area has dual NiFe active sites, where high‐valence Ni3+‐based edge‐sharing octahedral frameworks are surrounded by interstitial distorted Fe octahedra and contribute to the superior OER performance. This top‐down strategy provides a valid way to design novel perovskite‐derived catalysts.

Efficient electrocatalysts for hydrogen evolution reaction are key to realize clean hydrogen production through water splitting. As an important family of functional materials, transition metal oxides are generally believed inactive towards hydrogen evolution reaction, although many of them show high activity for oxygen evolution reaction. Here we report the remarkable electrocatalytic activity for hydrogen evolution reaction of a layered metal oxide, Ruddlesden−Popper-type Sr2RuO4 with alternative perovskite layer and rock-salt SrO layer, in an alkaline solution, which is comparable to those of the best electrocatalysts ever reported. By theoretical calculations, such excellent activity is attributed mainly to an unusual synergistic effect in the layered structure, whereby the (001) SrO-terminated surface cleaved in rock-salt layer facilitates a barrier-free water dissociation while the active apical oxygen site in perovskite layer promotes favorable hydrogen adsorption and evolution. Moreover, the activity of such layered oxide can be further improved by electrochemistry-induced activation.

Improving the catalytic efficiency of platinum for the hydrogen evolution reaction is valuable for water splitting technologies. Hydrogen spillover has emerged as a new strategy in designing binary-component Pt/support electrocatalysts. However, such binary catalysts often suffer from a long reaction pathway, undesirable interfacial barrier, and complicated synthetic processes. Here we report a single-phase complex oxide La2Sr2PtO7+δ as a high-performance hydrogen evolution electrocatalyst in acidic media utilizing an atomic-scale hydrogen spillover effect between multifunctional catalytic sites. With insights from comprehensive experiments and theoretical calculations, the overall hydrogen evolution pathway proceeds along three steps: fast proton adsorption on O site, facile hydrogen migration from O site to Pt site via thermoneutral La-Pt bridge site serving as the mediator, and favorable H2 desorption on Pt site. Benefiting from this catalytic process, the resulting La2Sr2PtO7+δ exhibits a low overpotential of 13 mV at 10 mA cm−2, a small Tafel slope of 22 mV dec−1, an enhanced intrinsic activity, and a greater durability than commercial Pt black catalyst.

The state-of-the-art active HER catalysts in acid media (e.g., Pt) generally lose considerable catalytic performance in alkaline media mainly due to the additional water dissociation step. To address this issue, synergistic hybrid catalysts are always designed by coupling them with metal (hydro)oxides. However, such hybrid systems usually suffer from long reaction path, high cost and complex preparation methods. Here, we discover a single-phase HER catalyst, SrTi0.7Ru0.3O3-δ (STRO) perovskite oxide highlighted with an unusual super-exchange effect, which exhibits excellent HER performance in alkaline media via atomic-scale synergistic active centers. With insights from first-principles calculations, the intrinsically synergistic interplays between multiple active centers in STRO are uncovered to accurately catalyze different elementary steps of alkaline HER; namely, the Ti sites facilitates nearly-barrierless water dissociation, Ru sites function favorably for OH* desorption, and non-metal oxygen sites (i.e., oxygen vacancies/lattice oxygen) promotes optimal H* adsorption and H2 desorption.

ABSTRACT:lnterpolymer complexation behavior between poly(p-vinylphenol) (PVPh) and three pyridine-containing polymers, poly(2-vinylpyridine) (P2VPy), poly(4-vinylpyridine) (P4VPy), and poly(2-vinylpyridine-co-styrene) (P2VPyS) with 70% vinylpyridine repeating units was studied. PVPh forms interpolymer complexes with the three pyridine-containing polymers over the whole feed composition range in ethanol solutions. The glass transition temperatures of the interpolymer complexes are remarkably higher than those calculated from the additivity rule, indicating strong favorable intermolecular interactions between unlike polymer chains. P2VPy has a stronger complexation ability with PVPh as compared with P2VPyS, showing the important role of pyridine group in achieving interpolymer complex formation. P4VPy shows a stronger complexation ability with PVPh as compared with P2VPy, demonstrating that the stereo-structure of repeating units affects interpolymer complex formation. When using N,N-dimethylformamide as solvent, complexation does not occur between PVPh and the three pyridine-containing polymers. Infrared studies of the complexes show the existence of hydrogen bonds between the phenolic hydroxyl groups and the nitrogens of pyridine groups, and the strength of interaction decreases in the order P4VPy > P2VPy > P2VPyS. KEY WORDSInterpolymer Complexes/ Poly(p-vinylphenol) / Poly(2-vinylpyridine) / Poly(4-vinylpyridine) / Poly(styrene-co-2-vinylpyridine) / Polymers usually require the presence of favorable interpolymer interactions in achieving miscibility, as the combinatorial entropy change is too small to produce a negative free energy of mixing. In certain cases when such specific favorable interpolymer interactions are strong enough, interpolymer complexation occurs as characterized by their peculiar viscosity, electrical conductivity and other properties. In addition, if the interpolymer interactions are superior to those between either of the polymer-solvent pairs, interpolymer complexes are obtained in the form of co-precipitation from their common solvent in which both component polymers are initially soluble.Recently, we investigated the complexation behavior between alcoholic hydroxyl-containing polymers and tertiary amide polymers. 1 -3 Interpolymer complexes are formed through intermolecular hydrogen bonding associations between hydroxyls and amide carbonyls which are present in different polymer chains. Pyridine-containing polymers can form hydrogen bonds with proton-donating group through sharing the valence electrons of pyridine nitrogen atoms. We 4 have previously reported that poly(4-vinylpyridine) (P4VPy) is immiscible with polysulfone (PSf) but is miscible with carboxylated polysulfone (CPSf) having degrees of carboxylation of 0.43-1.93, and can even form complexes in N,N-dimethylformamide (DMF) solutions when the feed is rich in CPSf. This result clearly indicates that there is a strong intermolecular interaction between * To whom correspondence should be addressed. 905J. DAI et al. pyridine ...

New reduced-temperature ceramic fuel cells with dual-ion conducting electrolyte and triple conducting double perovskite cathode.

Fabricating single-atom electrodes via atomic dispersion of active metal atoms into monolithic metal supports is of great significance to advancing the lab-tofab translation of the electrochemical technologies. Here, we report an inherent oxide anchoring strategy to fasten ligand-free isolated Ru atoms on the amorphous layer of monolithic Ti support by regulating the electronic metal-support interactions. The prepared Ru single atom electrode exhibited exceptional electrochemical chlorine evolution activity, three orders of magnitude higher mass activity than that of commercial dimensionally stable anode, and also selectively reduced nitrate to ammonia with an unprecedented ammonia yield rate of 22.2 mol g À 1 h À 1 at À 0.3 V. Furthermore, the Ru single atom monolithic electrode can be scaled up from 2 × 2 cm to 25 × 15 cm at least, thus demonstrating great potential for industrial electrocatalytic applications.

Constructing highly active electrocatalysts with superior stability at low cost is a must, and vital for the large‐scale application of rechargeable Zn–air batteries. Herein, a series of bifunctional composites with excellent electrochemical activity and durability based on platinum with the perovskite Sr(Co0.8Fe0.2)0.95P0.05O3−δ (SCFP) are synthesized via a facile but effective strategy. The optimal sample Pt‐SCFP/C‐12 exhibits outstanding bifunctional activity for the oxygen reduction reaction and oxygen evolution reaction with a potential difference of 0.73 V. Remarkably, the Zn–air battery based on this catalyst shows an initial discharge and charge potential of 1.25 and 2.02 V at 5 mA cm−2, accompanied by an excellent cycling stability. X‐ray photoelectron spectroscopy, X‐ray absorption near‐edge structure, and extended X‐ray absorption fine structure experiments demonstrate that the superior performance is due to the strong electronic interaction between Pt and SCFP that arises as a result of the rapid electron transfer via the PtOCo bonds as well as the higher concentration of surface oxygen vacancies. Meanwhile, the spillover effect between Pt and SCFP also can increase more active sites via lowering energy barrier and change the rate‐determining step on the catalysts surface. Undoubtedly, this work provides an efficient approach for developing low‐cost and highly active catalysts for wider application of electrochemical energy devices.