Platinum (Pt) is the state-of-the-art catalyst for oxygen reduction reaction (ORR), but its high cost and scarcity limit its large-scale use. However, if the usage of Pt reduces to a sufficiently low level, this critical barrier may be overcome. Atomically dispersed metal catalysts with high activity and high atom efficiency have the possibility to achieve this goal. Herein, we report a locally distributed atomic Pt-Co nitrogen-carbon-based catalyst (denoted as A-CoPt-NC) with high activity and robust durability for ORR (267 times higher than commercial Pt/C in mass activity). The A-CoPt-NC shows a high selectivity for the 4e pathway in ORR, differing from the reported 2e pathway characteristic of atomic Pt catalysts. Density functional theory calculations suggest that this high activity originates from the synergistic effect of atomic Pt-Co located on a defected C/N graphene surface. The mechanism is thought to arise from asymmetry in the electron distribution around the Pt/Co metal centers, as well as the metal atoms' coordination with local environments on the carbon surface. This coordination results from N8V4 vacancies (where N8 represents the number of nitrogen atoms and V4 indicates the number of vacant carbon atoms) within the carbon shell, which enhances the oxygen reduction reaction via the so-called synergistic effect.

Anterior debridement and bone grafting with posterior instrumentation may not be the best choice for treating patients with spinal tuberculosis. Single posterior debridement/bone grafting/instrumentation for single-segment of thoracic or lumbar spine tuberculosis produced good clinical results, except in patients who had a psoas abscess.

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Surface lattice oxygen in transition‐metal oxides plays a vital role in catalytic processes. Mastering activation of surface lattice oxygen and identifying the activation mechanism are crucial for the development and design of advanced catalysts. A strategy is now developed to create a spinel Co3O4 /perovskite La0.3Sr0.7CoO3 interface by in situ reconstruction of the surface Sr enrichment region in perovskite LSC to activate surface lattice oxygen. XAS and XPS confirm that the regulated chemical interface optimizes the hybridized orbital between Co 3d and O 2p and triggers more electrons in oxygen site of LSC transferred into lattice of Co3O4 , leading to more inactive O2− transformed into active O2−x. Furthermore, the activated Co3O4/LSC exhibits the best catalytic activities for CO oxidation, oxygen evolution, and oxygen reduction. This work would provide a fundamental understanding to explain the activation mechanism of surface oxygen sites.

Unsupervised feature learning for point clouds has been vital for large-scale point cloud understanding. Recent deep learning based methods depend on learning global geometry from self-reconstruction. However, these methods are still suffering from ineffective learning of local geometry, which significantly limits the discriminability of learned features. To resolve this issue, we propose MAP-VAE to enable the learning of global and local geometry by jointly leveraging global and local self-supervision. To enable effective local self-supervision, we introduce multi-angle analysis for point clouds. In a multi-angle scenario, we first split a point cloud into a front half and a back half from each angle, and then, train MAP-VAE to learn to predict a back half sequence from the corresponding front half sequence. MAP-VAE performs this half-to-half prediction using RNN to simultaneously learn each local geometry and the spatial relationship among them. In addition, MAP-VAE also learns global geometry via self-reconstruction, where we employ a variational constraint to facilitate novel shape generation. The outperforming results in four shape analysis tasks show that MAP-VAE can learn more discriminative global or local features than the state-of-the-art methods.

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well-tuned electronic configuration. [4,5] Especially, with an edge-sharing octahedral MO 6 layer-stacking crystal structure served as highly active sites, NiFe-based layered double hydroxides (NiFe LDHs) exhibited highly remarkable intrinsic electrochemical activity. [6,7] Several studies have reported that NiFe LDH is actually a precatalyst, and it heavily undergoes a self-reconstruction process in basic solution, generating Ni oxyhydroxide (NiOOH) as the active species for OER. [8,9] To begin with, Alexis et al. characterized the vibration mode of NiOOH by in situ Raman spectra, when Ni-Fe films worked as anodes in basic media during the OER. [10] Then, some research revealed that NiOOH species is generally recognized as the positive reaction species and can provide abundant intrinsic catalytic sites for OER. [11][12][13] Not limited to OER, NiOOH can also efficiently catalyze the anodic degradation of urea that featured with the more complex six-electron redox process. [14,15] However, owing to the instability of the high valence state of Ni (III) which can easily transform into Ni (II), the direct synthesis and application of NiOOH have not been realized, unless a high anodic polarization is applied. [16,17] Therefore, it is crucial to explore synthesis methods to stabilize NiOOH catalyst.Among the multiple regulation methods, surface structure reconstruction with the aid of a new phase is widely accepted as a controllable approach for synthesizing novel composites with NiOOH is considered as the most active intermediate during electrochemical oxidation reaction, however, it is hard to directly synthesize due to high oxidation energy. Herein, theoretical calculations predict that α-FeOOH enables a decline in formation energy and an improvement in stabilization of NiOOH in NiFe-based layered double hydroxide (LDH). Inspiringly, a composite composed of α-FeOOH and LDH is well-designed and successfully fabricated in hydrothermal treatment by adding extra Fe 3+ resource, and stable NiOOH is obtained by the following electro-oxidation method. Benefiting from strong electron-capturing capability of α-FeOOH, it efficiently promotes charge redistribution around the Ni/Fe sites and activates Ni atoms of LDH, verified by X-ray photoelectron spectra (XPS) and X-ray absorption spectra (XAS). The d-band center is optimized that balances the absorption and desorption energy, and thus Gibbs free energy barrier is lowered dramatically toward oxygen evolution reaction (OER) and urea oxidation reaction (UOR), and finally showing an outstanding overpotential of 195 mV and a potential of 1.35 V at 10 mA cm −2 , respectively. This study provides a novel strategy to construct highly efficient catalysts via the introduction of a new phase for complex multiple-electron reactions.

Spinel Co3O4, consisting of two mixed valence states, Co2+ and Co3+, has attracted enormous interest as a promising electrocatalyst for oxygen evolution reaction (OER). Proper control on the relative proportion of Co2+/Co3+ in cobalt oxide can greatly tune the electronic structure and further optimize its catalytic performance. Herein, a hybrid coupling Co3O4 with black phosphorus (Co3O4@BP) is designed as an efficient catalyst for OER. Electron migration from BP to Co3O4 is achieved in Co3O4@BP, owing to the higher Fermi level of BP than that of Co3O4. Efficient electron transfer can not only create massive active sites with abundant Co2+ but also remarkably suppress the deterioration of BP. Particularly, the Co3O4@BP catalyst outperforms the pristine Co3O4 by over four times and is even 20 times higher than that of bare BP at a potential of 1.65 V versus reversible hydrogen electrode. Our finding provides insightful understanding for electronic engineering in Co3O4@BP by balancing advantages and utilizing drawbacks of Co3O4 and BP.