Language：English   Publishing type：Research paper (scientific journal)   Publisher：Chemistry A European Journal  

A Lewis base-free trialumane having a 2,4,6-triisopropylphenyl (Tip) substituent was synthesized by a reaction of alumanyl anion with TipAlBr<inf>2</inf>. The structure, bonding, and electronic properties of the Tip-substituted trialumane were estimated by NMR spectra, X-ray crystallographic analysis, DFT calculations, X-ray photoelectron spectra, and electrochemical study to reveal its two consecutive Al─Al covalent bonds and overlapped vacant orbitals of three Al atoms. Chemical reduction of Tip-substituted trialumane gave a series of alumanyl anions via the cleavage of the Al─Al bonds. This study shows the low-lying characteristic LUMO that consists of vacant orbitals of three Al atoms in the base-free trialumane.

DOI： 10.1002/chem.202501315

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Angewandte Chemie International Edition  

Supported alloy catalysts have been extensively applied to many significant industrial chemical processes due to the abundant active sites with distinguishable geometry and electron states. However, a detailed in situ investigation of the interaction between support and alloy nanoparticles is still lacking. Here, a subversive ‘tearing effect’ on the interface of TiO<inf>2</inf>-supported NiRu alloy nanoparticles is in situ discovered by environmental transmission electron microscopy (ETEM) with a dramatic redispersion process of alloy nanoparticles from ~25 nm to 2–3 nm under the repeated hydrogen reduction. Dual-driven by the distinct alloy-support interaction involving the restructuring of alloy nanoparticles and growth of TiO<inf>x</inf> overlayer, larger NiRu alloy nanoparticles spontaneously disintegrate into atoms migrating on support. Atoms are finally captured by the defects generated on TiO<inf>2</inf> during the repeat reduction, which also confines the further growth of the newly alloy nanoparticles. Owing to this specific alloy-support interaction, smaller alloy nanoparticles on TiO<inf>2</inf> support are much more stable than the bigger ones, which holds promise for industrial applications as durable catalysts. This novel metal-support interaction with the ‘tearing effect’ revealed on supported alloy catalysts provides new knowledge on the structure-performance relationships in all the alloy catalysts for hydrogenation reactions.

DOI： 10.1002/anie.202425066

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACS Applied Polymer Materials  

To construct an environmentally friendly crystalline proton conductor and establish a composition-structure-function relationship, polyoxometalate and poly(vinyl alcohol), an anionic metal-oxide cluster, and a polymer with hydroxyl groups, respectively, providing proton carriers and conduction pathways, were combined with a lanthanide ion with a large coordination sphere to trap water effectively. The crystalline composite exhibited a high proton conductivity of 8.3 × 10^-3 S cm^-1 at 368 K and 75% relative humidity. We demonstrate the potential for achieving high performance under mild humidification with a simple polymer like poly(vinyl alcohol).

DOI： 10.1021/acsapm.4c01069

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Physical Chemistry Chemical Physics  

Transition-metal-incorporated cerium oxides with Cu and a small amount of Ru (Cu<inf>0.18</inf>Ru<inf>0.05</inf>CeO<inf>z</inf>) were prepared, and their low-temperature redox performance (<423 K) and catalytic alcohol ammoxidation performance were investigated. Temperature-programmed reduction/oxidation under H<inf>2</inf>/O<inf>2</inf> and in situ X-ray absorption fine structure revealed the reversible redox behavior of the three metals, Cu, Ru, and Ce, in the low-temperature redox processes. The initially reduced Ru species decreased the reduction temperature of Cu oxides and promoted the activation of Ce species. Cu<inf>0.18</inf>Ru<inf>0.05</inf>CeO<inf>z</inf> selectively catalyzed the production of benzonitrile in the ammoxidation of benzyl alcohol. H<inf>2</inf>-treated Cu<inf>0.18</inf>Ru<inf>0.05</inf>CeO<inf>z</inf> showed a slightly larger initial conversion of benzyl alcohol than O<inf>2</inf>-treated Cu<inf>0.18</inf>Ru<inf>0.05</inf>CeO<inf>z</inf>, suggesting that the reduced structure of Cu<inf>0.18</inf>Ru<inf>0.05</inf>CeO<inf>z</inf> was active for the ammoxidation. The integration of both Cu and Ru resulted in the efficient promotion of ammoxidation, in which the Ru species were involved in the conversion of benzyl alcohol and Cu species were required for selective production of benzonitrile.

DOI： 10.1039/d4cp01432d

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Catalysis Science and Technology  

The local structures and oxygen reduction reaction (ORR) performances of Pt-Cu fuel-cell electrocatalysts on robust TiN nanoparticles were investigated. The structures of the PtCu/TiN catalysts were fully characterized by XRF, XRD, TEM, STEM-EDS, XAFS, and XPS, which revealed that loaded Cu was partially alloyed with Pt and fine Pt-Cu alloy nanoparticles (2-3 nm) were formed on TiN. The alloying of Cu to Pt was saturated at the Cu/Pt molar ratio (X) of 1.0 and the fraction of Cu in the alloy structure was estimated to be 40%. The ORR activity was found to be affected by the formation of the Pt-Cu alloy structure, and the electrocatalytic activity enhanced with increasing X. Notably, the best ORR performance was obtained at X = 1 and further Cu loading produced cationic Cu²⁺ species, which did not improve the ORR activity. We also evaluated the performance of the PtCu/TiN catalyst (X = 1) on a PEFC MEA, which showed 1.5 times higher mass-specific power density, compared to an MEA with a commercial Pt/C catalyst, and significant durability (70% of ECSA after 80 000 cycles of the typical accelerated degradation test of the PEFC).

DOI： 10.1039/d3cy01438j

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