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To meet the requirements of potential applications, it is of great importance to explore new catalysts for formic acid oxidation that have both ultra-high mass activity and CO resistance. Here, we successfully synthesize atomically dispersed Rh on N-doped carbon (SA-Rh/CN) and discover that SA-Rh/CN exhibits promising electrocatalytic properties for formic acid oxidation. The mass activity shows 28- and 67-fold enhancements compared with state-of-the-art Pd/C and Pt/C, respectively, despite the low activity of Rh/C. Interestingly, SA-Rh/CN exhibits greatly enhanced tolerance to CO poisoning, and Rh atoms in SA-Rh/CN resist sintering after long-term testing, resulting in excellent catalytic stability. Density functional theory calculations suggest that the formate route is more favourable on SA-Rh/CN. According to calculations, the high barrier to produce CO, together with the relatively unfavourable binding with CO, contribute to its CO tolerance.Atomically dispersed Rh on N-doped carbon exhibits 28- and 67-fold enhancements compared with state-of-the-art Pd/C and Pt/C, despite the low activity of Rh/C. The Rh single atoms exhibit high tolerance to CO poisoning compared to Rh nanoparticles.

The selective hydrogenation of CO 2 to value-added chemicals is attractive but still challenged by the high-performance catalyst. In this work, we report that gallium nitride (GaN) catalyzes the direct hydrogenation of CO 2 to dimethyl ether (DME) with a CO-free selectivity of about 80%. The activity of GaN for the hydrogenation of CO 2 is much higher than that for the hydrogenation of CO although the product distribution is very similar. The steady-state and transient experimental results, spectroscopic studies, and density functional theory calculations rigorously reveal that DME is produced as the primary product via the methyl and formate intermediates, which are formed over different planes of GaN with similar activation energies. This essentially differs from the traditional DME synthesis via the methanol intermediate over a hybrid catalyst. The present work offers a different catalyst capable of the direct hydrogenation of CO 2 to DME and thus enriches the chemistry for CO 2 transformations. The conversion of CO 2 to valuable chemicals is still challenged by catalyst developments. Herein, the authors found that GaN is an efficient catalyst for selective CO 2 hydrogenation to dimethyl ether as the primary product, in contrast to the traditional methanol-intermediate route over hybrid catalysts.

Identification on catalytic sites of heterogeneous catalysts at atomic level is important to understand catalytic mechanism. Surface engineering on defects of metal oxides can construct new active sites and regulate catalytic activity and selectivity. Here we outline the strategy by controlling surface defects of nanoceria to create the solid frustrated Lewis pair (FLP) metal oxide for efficient hydrogenation of alkenes and alkynes. Porous nanorods of ceria ( PN -CeO 2 ) with a high concentration of surface defects construct new Lewis acidic sites by two adjacent surface Ce 3+ . The neighbouring surface lattice oxygen as Lewis base and constructed Lewis acid create solid FLP site due to the rigid lattice of ceria, which can easily dissociate H–H bond with low activation energy of 0.17 eV. Surface engineering of catalysts allows the tailoring of active sites. Here the authors produce a heterogeneous nanoceria catalyst with engineered defects producing active solid frustrated Lewis pair sites, and use these materials for the hydrogenation of alkynes and alkenes.

Single-atom precious metal catalysts hold the promise of perfect atom utilization, yet control of their activity and stability remains challenging. Here we show that engineering the electronic structure of atomically dispersed Ru 1 on metal supports via compressive strain boosts the kinetically sluggish electrocatalytic oxygen evolution reaction (OER), and mitigates the degradation of Ru-based electrocatalysts in an acidic electrolyte. We construct a series of alloy-supported Ru 1 using different PtCu alloys through sequential acid etching and electrochemical leaching, and find a volcano relation between OER activity and the lattice constant of the PtCu alloys. Our best catalyst, Ru 1 –Pt 3 Cu, delivers 90 mV lower overpotential to reach a current density of 10 mA cm −2 , and an order of magnitude longer lifetime over that of commercial RuO 2 . Density functional theory investigations reveal that the compressive strain of the Pt skin shell engineers the electronic structure of the Ru 1 , allowing optimized binding of oxygen species and better resistance to over-oxidation and dissolution. While Ru-based electrocatalysts are among the most active for acidic water oxidation, they suffer from severe deactivation. Now, Yuen Wu, Wei-Xue Li and co-workers report a core–shell Ru 1 –Pt 3 Cu catalyst with surface-dispersed Ru atoms for a highly active and stable oxygen evolution reaction in acid electrolyte.

In this work, a series of novel Cu 2 O@sponge composite materials including cubic Cu 2 O@sponges, octahedral Cu 2 O@sponges and cubo-octahedral Cu 2 O@sponges were prepared through a facile dip coating method to coat Cu 2 O particles on melamine sponge, all of which possess very highly hydrophobic and oleophilic properties. The crystal phase, microstructure and surface functional group of the as-prepared materials were characterized by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectra. The effect of different crystal facet of Cu 2 O on contact angle, wettability and oil absorption was systematically investigated. Meanwhile, the DFT calculation results show that the surface energy has significant influence on the hydrophobic property of Cu 2 O, and the calculated surface energies of Cu 2 O (111) and Cu 2 O (100) crystal surface are 0.73 and 1.29 J/m 2 , respectively. On basis of the DFT calculations and experimental results, the octahedral Cu 2 O with eight (111) crystal facet-coated sponges has the highest hydrophobic properties with the contact angle of 149°, which therefore shows very high separation efficiency in oil/water separation and quickly absorbs floating oils on the water surface. Additionally, all the Cu 2 O@sponges composite materials indicate excellent oil absorption performances and reusability in terms of hydrophobicity and oil absorbency, which would provide new materials for the potential application of oil/water separation.

Activation of molecular O2 is the most critical step in gold-catalyzed oxidation reactions; however, the underlying mechanisms of this process remain under debate. In this study, we propose an alternative O2 activation pathway with the assistance of hydrogen-containing substrates using density functional theory. It is demonstrated that the co-adsorbed H-containing substrates （R-H） not only enhance the adsorption of O2, but also transfer a hydrogen atom to the adjacent O2, leading to O2 activation by its transformation to a hydroperoxyl （OOH） radical species. The activation barriers of the H-transfer from 16 selected R-H compounds （H2O, CH3OH, NH2CHCOOH, CH3CH=CH2, （CH3）2SiH2, etc.） to the co-adsorbed O2 are lower than 0.50 eV in most cases, indicating the feasibility of the activation of O2 via OOH under mild conditions. The formed OOH oxidant, with an increased O-O bond length of -1.45 A, either participates directly in oxidation reactions through the end-on oxygen atom, or dissociates into atomic oxygen and hydroxyl （OH） by crossing a fairly low energy barrier of 0.24 eV. Using CO oxidation as a probe, we have found that OOH has superior activity than activated O2 and atomic oxygen. This study reveals a new pathway for the activation of O2, and may provide insight into the oxidation catalysis of nanosized gold.

Cross-media analysis and reasoning is an active research area in computer science, and a promising direction for artificial intelligence. However, to the best of our knowledge, no existing work has summarized the state-of-the-art methods for cross-media analysis and reasoning or presented advances, challenges, and future directions for the field. To address these issues, we provide an overview as follows： （1） theory and model for cross-media uniform representation; （2） cross-media correlation understanding and deep mining; （3） cross-media knowledge graph construction and learning methodologies; （4） cross-media knowledge evolution and reasoning; （5） cross-media description and generation; （6） cross-media intelligent engines; and （7） cross-media intelligent applications. By presenting approaches, advances, and future directions in cross-media analysis and reasoning, our goal is not only to draw more attention to the state-of-the-art advances in the field, but also to provide technical insights by discussing the challenges and research directions in these areas.

Three kinds of membranes were prepared from suspensions containing polyacrylonitrile, dimethyl sulfoxide, polyethylene glycol and different amount of Fe3O4 by the phase inversion process. The rejection rate and the flux of membrane were investigated in the filtration of pig blood solution. SEM also studied the morphologies of fouled membranes. The permeate flux and the rejection rate decline fast in the initial several minutes and then change slowly. The magnetized membrane has a higher flux and a relative flux than the corresponding non-magnetized membrane. And the magnetized membrane containing about 3 wt% Fe3O4 has a prominent anti-fouling performance with above 52% relative flux. The results indicate that the magnetized ferrosoferric oxide-polyacrylonitrile membranes are promising in the recovery of blood proteins in the slaughterhouse effluents. In addition, the hydraulic resistance model explained results and the fouling mechanism was also given.

In this work, a series of novel Cu.sub.2O@sponge composite materials including cubic Cu.sub.2O@sponges, octahedral Cu.sub.2O@sponges and cubo-octahedral Cu.sub.2O@sponges were prepared through a facile dip coating method to coat Cu.sub.2O particles on melamine sponge, all of which possess very highly hydrophobic and oleophilic properties. The crystal phase, microstructure and surface functional group of the as-prepared materials were characterized by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectra. The effect of different crystal facet of Cu.sub.2O on contact angle, wettability and oil absorption was systematically investigated. Meanwhile, the DFT calculation results show that the surface energy has significant influence on the hydrophobic property of Cu.sub.2O, and the calculated surface energies of Cu.sub.2O (111) and Cu.sub.2O (100) crystal surface are 0.73 and 1.29 J/m.sup.2, respectively. On basis of the DFT calculations and experimental results, the octahedral Cu.sub.2O with eight (111) crystal facet-coated sponges has the highest hydrophobic properties with the contact angle of 149°, which therefore shows very high separation efficiency in oil/water separation and quickly absorbs floating oils on the water surface. Additionally, all the Cu.sub.2O@sponges composite materials indicate excellent oil absorption performances and reusability in terms of hydrophobicity and oil absorbency, which would provide new materials for the potential application of oil/water separation.

Activation of molecular O sub(2) is the most critical step in gold-catalyzed oxidation reactions; however, the underlying mechanisms of this process remain under debate. In this study, we propose an alternative O sub(2) activation pathway with the assistance of hydrogen-containing substrates using density functional theory. It is demonstrated that the co-adsorbed H-containing substrates (R-H) not only enhance the adsorption of O sub(2), but also transfer a hydrogen atom to the adjacent O sub(2), leading to O sub(2) activation by its transformation to a hydroperoxyl (OOH) radical species. The activation barriers of the H-transfer from 16 selected R-H compounds (H sub(2)O, CH sub(3)OH, NH sub(2)CHCOOH, CH sub(3)CH=CH sub(2), (CH sub(3)) sub(2)SiH sub(2 ), etc.) to the co-adsorbed O sub(2) are lower than 0.50 eV in most cases, indicating the feasibility of the activation of O sub(2) via OOH under mild conditions. The formed OOH oxidant, with an increased O-O bond length of ~1.45 Aa, either participates directly in oxidation reactions through the end-on oxygen atom, or dissociates into atomic oxygen and hydroxyl (OH) by crossing a fairly low energy barrier of 0.24 eV. Using CO oxidation as a probe, we have found that OOH has superior activity than activated O sub(2) and atomic oxygen. This study reveals a new pathway for the activation of O sub(2), and may provide insight into the oxidation catalysis of nanosized gold. [Figure not available: see fulltext.]