This review highlights the recent progress in porous materials (MOFs, zeolites, POPs, nanoporous carbons, and mesoporous materials) for CO₂ capture and conversion.

We report magnetism in carbon doped ZnO. Our first-principles calculations based on density functional theory predicted that carbon substitution for oxygen in ZnO results in a magnetic moment of 1.78 µ B per carbon. The theoretical prediction was confirmed experimentally. Cdoped ZnO films deposited by pulsed laser deposition with various carbon concentrations showed ferromagnetism with Curie temperatures higher than 400 K, and the measured magnetic moment based on the content of carbide in the films (1.5 − 3.0µ B per carbon) is in agreement with the theoretical prediction. The magnetism is due to bonding coupling between Zn ions and doped C atoms. Results of magneto-resistance and abnormal Hall effect show that the doped films are ntype semiconductors with intrinsic ferromagnetism. The carbon doped ZnO could be a promising room temperature dilute magnetic semiconductor (DMS) and our work demonstrates possiblity of produing DMS with non-metal doping.

Single-crystalline Ni nanowires have been successfully fabricated with anodic aluminum oxide as template by electrodeposition. Structural characterization (X-ray diffraction, XRD, and high-resolution transmission electron microscopy, HRTEM) shows that the single-crystalline Ni nanowire has a preferred orientation along the [220] direction. The effects of electrochemical deposition conditions on the structure of Ni nanowires are systematically studied to investigate the growth mechanism. Possible reasons for the growth of the single-crystalline Ni nanowires were discussed on the basis of electrochemistry and thermodynamics. These single-crystalline Ni nanowires have exhibited excellent magnetic properties (large anisotropy, large coercivity, and high remanence). By a similar process, single-crystalline Co nanowires with hexagonal close-packed (hcp) structure were achieved, also having large anisotropy, large coercivity (1.8 kOe), and high remanence ratio (80.8%).

We report direct evidence of room-temperature ferromagnetic ordering in O-deficient ZnO:Cu films by using soft x-ray magnetic circular dichroism and x-ray absorption. Our measurements have revealed unambiguously two distinct features of Cu atoms associated with (i) magnetically ordered Cu ions present only in the oxygen-deficient samples and (ii) magnetically disordered regular Cu2+ ions present in all the samples. We find that a sufficient amount of both oxygen vacancies (V(O)) and Cu impurities is essential to the observed ferromagnetism, and a non-negligible portion of Cu impurities is uninvolved in the magnetic order. Based on first-principles calculations, we propose a microscopic "indirect double-exchange" model, in which alignments of localized large moments of Cu in the vicinity of the V(O) are mediated by the large-sized vacancy orbitals.

We report a general thermal transformation approach to synthesize single-crystalline magnetic transition metal oxides nanotubes/nanorings including magnetite Fe(3)O(4), maghematite gamma-Fe(2)O(3), and ferrites MFe(2)O(4) (M = Co, Mn, Ni, Cu) using hematite alpha-Fe(2)O(3) nanotubes/nanorings template. While the straightforward reduction or reduction-oxides process was employed to produce Fe(3)O(4) and gamma-Fe(2)O(3), the alpha-Fe(2)O(3)/M(OH)(2) core/shell nanostructure was used as precursor to prepare MFe(2)O(4) nanotubes via MFe(2)O(4-x) (0 < x < 1) intermediate. The transformed ferrites nanocrystals retain the hollow structure and single-crystalline nature of the original templates. However, the crystallographic orientation-relationships of cubic spinel ferrites and trigonal hematite show strong correlation with their morpologies. The hollow-structured MFe(2)O(4) nanocrystals with tunable size, shape, and composition have exhibited unique magnetic properties. Moreover, they have been demonstrated as a highly effective peroxidase mimic catalysts for laboratory immunoassays or as a universal nanocapsules hybridized with luminescent QDs for magnetic separation and optical probe of lung cancer cells, suggesting that these biocompatible magnetic nanotubes/nanorings have great potential in biomedicine and biomagnetic applications.

Developing cost-effective, high-performance nitrogen reduction reaction (NRR) electrocatalysts is required for the production of green and low-cost ammonia under ambient conditions. Here, a strategy is proposed to adjust the reaction preference of noble metals by tuning the size and local chemical environment of the active sites. This proof-of-concept model is realized by single ruthenium atoms distributed in a matrix of graphitic carbon nitride (Ru SAs/g-C 3 N 4 ). This model is compared, in terms of the NRR activity, to bulk Ru. The as-synthesized Ru SAs/g-C 3 N 4 exhibits excellent catalytic activity and selectivity with an NH 3 yield rate of 23.0 µg mg cat −1 h −1 and a Faradaic efficiency as high as 8.3% at a low overpotential (0.05 V vs the reversible hydrogen electrode), which is far better than that of the bulk Ru counterpart. Moreover, the Ru SAs/g-C 3 N 4 displays a high stability during five recycling tests and a 12 h potentiostatic test. Density functional theory calculations reveal that compared to bulk Ru surfaces, Ru SAs/g-C 3 N 4 has more facile reaction thermodynamics, and the enhanced NRR performance of Ru SAs/g-C 3 N 4 originates from a tuning of the d-electron energies from that of the bulk to a single-atom, causing an up-shift of the d-band center toward the Fermi level.can maximize metal utilization. Since SACs have unique catalytic sites, they usually exhibit a distinct catalytic selectivity as compared to their nanoclusters or nanoparticle counterparts. [2] For example, single atomic Pt immobilized in the surface of Ni nanocrystals shows a higher activity and chemoselectivity toward the hydrogenation of 3-nitrostyrene. [3] Isolated Co single-site catalysts anchored on a N-doped porous carbon nanobelt exhibits an excellent catalytic performance for oxidation of ethylbenzene with 98% conversion and 99% selectivity, whereas the Co nanoparticles are essentially inert. [4] Moreover, atomic Ni-anchored covalent triazine framework has a remarkable selectivity for the conversion of CO 2 to CO, with a Faradaic efficiency (FE) of > 90% over the range of −0.6 to −0.9 V versus the reversible hydrogen electrode (RHE). [5] In view of these reported works, it is evident that the size of metal particles is a key factor in determining their catalytic performance, and decreasing the size offers an intriguing opportunity to alter the activity and selectivity of these metal catalysts. SACs, as the limit of size reduction, hold great potential to achieve high activity and selectivity in catalytic reactions.Recently, the electrocatalytic N 2 reduction reaction (NRR) in aqueous electrolytes for synthesizing ammonia at ambient

A combined experimental and computational study was carried out to investigate magnetic properties of NiO nanostructures. Remarkable size-dependent magnetism was discovered. Uniform amorphous NiO showed a dominated antiferromagnetic interaction and an ordering temperature of 3.5 K. NiO clusters ͑up to 1 nm͒ tend to be ferromagnetic interaction with an ordering temperature of 35 K, accompanied by high magnetization ͑105 emu/ g͒ and a spin-glass behavior. NiO nanocrystals ͑Ͼ2 nm͒ were found to be antiferromagnetic with uncompensated surface magnetization and shifted hysteresis due to the core-shell interactions.

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