A high performance Pt-free cathode catalyst for polymer electrolyte fuel cells has been synthesized by the multi-step pyrolysis of polyimide fine particles with a diameter of about 100 nm.

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Although the structure and properties of water under conditions of extreme confinement are fundamentally important for a variety of applications, they remain poorly understood, especially for dimensions less than 2 nm. This problem is confounded by the difficulty in controlling surface roughness and dimensionality in fabricated nanochannels, contributing to a dearth of experimental platforms capable of carrying out the necessary precision measurements. In this work, we utilize an experimental platform based on the interior of lithographically segmented, isolated single-walled carbon nanotubes to study water under extreme nanoscale confinement. This platform generates multiple copies of nanotubes with identical chirality, of diameters from 0.8 to 2.5 nm and lengths spanning 6 to 160 μm, that can be studied individually in real time before and after opening, exposure to water, and subsequent water filling. We demonstrate that, under controlled conditions, the diameter-dependent blue shift of the Raman radial breathing mode (RBM) between 1 and 8 cm–1 measures an increase in the interior mechanical modulus associated with liquid water filling, with no response from exterior water exposure. The observed RBM shift with filling demonstrates a non-monotonic trend with diameter, supporting the assignment of a minimum of 1.81 ± 0.09 cm–1 at 0.93 ± 0.08 nm with a nearly linear increase at larger diameters. We find that a simple hard-sphere model of water in the confined nanotube interior describes key features of the diameter-dependent modulus change of the carbon nanotube and supports previous observations in the literature. Longer segments of 160 μm show partial filling from their ends, consistent with pore clogging. These devices provide an opportunity to study fluid behavior under extreme confinement with high precision and repeatability.

A dual catalyst system has been developed for tandem hydroformylation/hydrogenation to produce n‐undecanol from 1‐decene in one pot. A combination of xantphos/[Rh(acac)(CO)2] and Shvo's catalyst (1) afforded the best results (see scheme; acac=acetylacetonate, DMA=N,N‐dimethylacetamide). Polar solvents effectively suppressed the formation of undecyl formate.

A volleyball is hit from the academic to the industrial side of the net and symbolizes the potential utility of a new dual catalyst system—a combination of xantphos/[Rh(acac)(CO)2] and Shvo's catalyst—in both fields. In their Communication on page  ff. K. Nozaki et al. describe the highly efficient production of n‐undecanol using syngas and this catalytic system. The one‐pot process involves hydroformylation catalyzed by rhodium and hydrogenation catalyzed by ruthenium.

Linear 1-alkanols (n-alcohols) are widely used in industry as precursors of detergents and plasticizers. [1] Direct and selective conversion of a terminal olefin into an n-alcohol by regioselective hydration is considered an ideal process, and it is referred to as one of the "ten challenges for catalysis". [2] In reality, current industrial production of n-alcohols mostly employs a two-step process consisting of hydroformylation of terminal olefins, purification of n-aldehydes, and then hydrogenation of n-aldehydes to n-alcohols. A one-pot tandem hydroformylation/hydrogenation reaction would be an attractive alternative for n-alcohol production. [3] A one-pot process would be advantageous over the two-step process in the following way: 1) a one-pot process simplifies the process operation, and 2) syngas (a mixture of H 2 and CO) can be directly used for hydrogenation instead of using hydrogen purified from syngas via membrane separation. [4] Therefore, there have been many reports on the tandem hydroformylation/hydrogenation for direct synthesis of alcohols with alkylphosphine ligands using metal catalysts, such as Co, [5] Rh, [6] Ru, [7] and Pd, [8] . Although these tandem systems gave a mixture of n-and i-alcohols in good yields (mostly > 90 %), a significant amount of alkane was often given. The most problematic issue is the low normal/iso selectivities (n/i < 8) in the hydroformylation step, causing a low n-alcohol yield (up to 81 %). Recently, a supramolecular catalyst system containing Rh and an acyl guanidine-tethered triphenylphosphine ligand was reported as an effective catalyst for the one-pot conversion of olefins into the corresponding homologated linear alcohols in up to 72 % yield. [9] Earlier this year a Cole-Hamilton and co-workers proposed a new strategy wherein two ligands were mixed for Rh-catalyzed hydroformylation/ hydrogenation in a one-pot process to provide linear alcohols in up to 87% yield. [6f] While these systems depend on one single metal catalyst to perform the two different reactions, we became interested in the admixture of two catalysts, each of which operates one reaction with high efficiency without disturbing the other reaction. [10] Herein, we report a highyielding synthesis of n-alcohol (> 90 %) by the reaction of a terminal olefin with syngas using Rh/xantphos [11] and Shvos catalyst [12] together in one pot.For the linear-selective hydroformylation, we selected an Rh/xantphos catalyst. [11] Xantphos is known to provide the excellent levels of linear selectivity in hydroformylation of terminal olefins and is a triarylphosphine ligand, which is stable in the presence of the generated alcohols. For aldehyde-selective hydrogenation over the coexisting olefins, we selected a ruthenium-based ligand-metal bifunctional catalysts. Such a catalyst converts dihydrogen into two nonequivalent hydrogen atoms; one is protic and the other is hydridic. [13] Both of the hydrogen atoms simultaneously interact with a substrate via a polar transition state in an outer-sphere mechanism. As a re...

A series of 2,2'-bis[(dialkylphosphino)methyl]biphenyls (alkyl-BISBIs) were synthesized and applied to the tandem hydroformylation-hydrogenation of 1-decene. The alkyl-BISBI ligands with "small" primary alkyl groups such as methyl or n-hexyl groups on the phosphorus atoms provided 1-alkanols selectively, whereas those with larger alkyl groups such as isopropyl or neopentyl groups showed much lower conversion from alkanals to alkanols. Observation of rhodium complexes of the BISBI-type ligands under H(2)/CO atmosphere revealed that the presence of a stable [RhH(CO)(2)(ligand)] species seems to be less favorable for the second step, the hydrogenation of aldehydes.

There has been recent interest in understanding the transport of nanoconfined fluids through single-digit nanopores (SDNs) or those smaller than 10 nm in diameters, where confinement alters the fluid structure and intermolecular potential. Thermal measurements on such systems are crucial to extracting phase boundaries and the thermodynamic properties of fluids under extreme confinement. In this work, we introduce a metrology approach based on micro-Raman spectroscopy of isolated, free-standing replicates of the identical chirality carbon nanotube suspended over windows between 17 and 200 μm in length to assess spatial variations in axial thermal conduction from segment to segment and upon filling with water. We show that a mathematical heat transfer model based on Fourier's law and diffusive phonon transport can be applied to extract estimates of the thermal conductivity κ. Accounting for nearly a 50% variation among different segments of the same chirality tube, the technique allows revealing the impact of fluid confinement. Our measurements indicate that nanoconfined water enhances acoustic phonon scattering impeding axial transport through SDNs, with a (17,9) carbon nanotube showing a reduction of 10 −3 m K/W. This newfound understanding and thermal measurements on nanoconfined water in carbon nanotube SDNs will advance both theory and experiment of fluids constrained to extreme volumes.