In this work, ruthenium (Ru) catalysts supported on CeO2 nanorods (NR), nanocubes (NC), and nanoctahedra (NO) were comparatively investigated to correlate the shape and exposed surface planes ({100}, {110}, and {111}) of nanoscale CeO2 supports with their low-temperature CO oxidation activity. Within the 5Ru/CeO2-r catalysts with three morphologies after reduction treatment, the Ru supported on CeO2 NR exhibited enhanced low-temperature (<100 °C) hydrogen consumption and superior room-temperature CO oxidation activity (∼9% CO conversion). Both X-ray photoelectron spectroscopy and X-ray absorption spectroscopy measurements revealed that Ru n+ homogeneously predominates the 5Ru/CeO2NR-r, which is very different from partial metallic Ru0 supported on CeO2 NC and NO, indicating the strong metal–support interaction formation between Ru and CeO2 NR by Ru ions diffusing into CeO2 surface lattice or forming Ru–O–Ce bonds at the interface. The enriched surface defects on the exposed {111} planes of CeO2 NR support are believed to be the key to the formation of cationic Ru species, which is of vital importance for the superior room-temperature CO oxidation activity of the 5Ru/CeO2NR-r catalyst. The higher surface oxygen vacancy concentration on 5Ru/CeO2NR-r than those on the CeO2 NC and NO is also crucial for adsorption/dissociation of oxygen in achieving low-temperature CO oxidation activity.

Wearable strain sensors are essential for the realization of applications in the broad fields of remote healthcare monitoring, soft robots, and immersive gaming, among many others. These flexible sensors should be comfortably adhered to the skin and capable of monitoring human motions with high accuracy, as well as exhibiting excellent durability. However, it is challenging to develop electronic materials that possess the properties of skin compliant, elastic, stretchable, and self-healable. This work demonstrates a new regenerative polymer complex composed of poly(2-acrylamido-2-methyl-1-propanesulfonic acid), polyaniline, and phytic acid as a skin-like electronic material. It exhibits ultrahigh stretchability (1935%), repeatable autonomous self-healing ability (repeating healing efficiency >98%), quadratic response to strain (R 2 > 0.9998), and linear response to flexion bending (R 2 > 0.9994), outperforming current reported wearable strain sensors. The deprotonated polyelectrolyte, multivalent anion, and doped conductive polymer, under ambient conditions, synergistically construct a regenerative dynamic network of polymer complex cross-linked by hydrogen bonds and electrostatic interactions, which enables ultrahigh stretchability and repeatable self-healing. Sensitive strainresponsive geometric and piezoresistive mechanisms of the material owing to the homogeneous and viscoelastic nature provide excellent linear responses to omnidirectional tensile strain and bending deformations. Furthermore, this material is scalable and simple to process in an environmentally friendly manner, paving the way for the next-generation flexible electronics.

With the ever-growing concerns for sustainable energy production and clean air, developing highly efficient catalysts to eliminate exhaust emission pollutants is of vital importance. In this work, we report a class of thermally stable RuO x –CeO2 nanofiber catalysts derived from a facile one-pot electrospinning method. Ru–CeO2 nanofiber catalysts exhibit outstanding low-temperature activity (∼90% conversion of CO below 150 °C) and long-term durability. The as-prepared Ru–CeO2 nanofiber catalysts show a high Brunauer–Emmett–Teller (BET) surface area (>110 m2/g), demonstrating the effectiveness of electrospinning for fabricating high-surface-area catalysts. The Ru–CeO2 nanofiber catalysts have a hollow interior and porous exterior structure, particularly at the Ru–CeO2 nanofiber interfaces, providing plentiful accessible CO and oxygen adsorption sites, which are beneficial for CO catalytic oxidation. H2 temperature-programmed reduction (H2-TPR) was applied to probe the reducibility of the as-synthesized catalysts. The reduced Ru–CeO2 nanofiber catalysts exhibited hydrogen consumption near room temperature. The catalysts were further characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) to explore the relationship between the microstructure and extraordinary low-temperature reducibility, as well as the CO oxidation activity. In addition, X-ray photoelectron spectroscopy (XPS), in situ CO-diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and density functional theory (DFT) calculation were employed to investigate the chemical states of the active surface species and identify the gas adsorption and reaction sites.

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