Magnetic nanoparticles (MNPs) with a core diameter of 30 nm comprising several iron oxide crystals, a poly(glycidyl methacrylate) (PGMA) shell with a thickness of 30 nm, and a surface coated with chloroperoxidase (CPO) were facilely fabricated as a nanobiocatalyst for asymmetric sulfoxidation. The covalently bound CPO did not change the original conformation of the active site and showed the same catalytic activity and enantioselectivity as free CPO for the sulfoxidation of thioanisole to produce (R)-methyl phenyl sulfoxide in >99% ee. The thick PGMA shell significantly increased the stability of the nanobiocatalyst: no loss of the sulfoxidation activity was observed after 11 times of recycling and reuse of the catalyst. Thus, the nanobiocatalyst fabricated here showed the best performance among nanosized biocatalyst particles regarding both the retaining of free enzyme activity and the recycling of catalyst. This is also the first example of a nanobiocatalyst for asymmetric oxidation, and the concept could be generally applicable for fabricating active and recyclable nanobiocatalysts.

Agriculture accounts for approximately 11% of China?s national greenhouse gas (GHG) emissions. Through adoption of region-specific best management practices, Chinese farmers can contribute to emission reduction while maintaining food security for its large population (>1300 Million). This paper presents the outcome of a bottom?up assessment to quantify technical potential of mitigation measures for Chinese agriculture using meta-analysis of data from 240 publications for cropland, 67 publications for grassland and 139 publications for livestock, and provides the reference scenario for the cost analysis of identified mitigation measures. Management options with greatest mitigation potential for rice, or rice-based cropping systems are conservation tillage, controlled irrigation; replacement of urea with ammonium sulphate, nitrogen (N) inhibitor application, reduced N fertilizer application, integrated rice-fish-duck farming and biochar application. A 15% reduction in current average synthetic N fertilizer application for rice in China i.e., 231 kg N ha?1, would result in 12% decrease in direct soil nitrous oxide (N2O) emissions. Combined application of chemical and organic fertilizer, conservation tillage, biochar application and reduced N application are possible measures that can reduce overall GHG emissions from upland cropping systems. Conventional fertilizer inputs for greenhouse vegetables are more than 2?8 times the optimal crop nutrient demand. A 20?40% reduction in N fertilizer application to vegetable crops can reduce N2O emissions by 32?121%, while not negatively impacting the yield. One of the most important mitigation measures for agricultural grasslands could be conversion of low yielding cropland, particularly on slopes, to shrub land or grassland, which is also a promising option to decrease soil erosion. In addition, grazing exclusion and reduced grazing intensity can increase SOC sequestration and decrease overall emissions while improving the largely degraded grasslands. For livestock production, where poor quality forage is commonly fed, improving grazing management and diet quality can reduce methane (CH4) emissions by 11% and 5%, on average. Dietary supplements can reduce CH4 emissions further, with lipids (15% reduction) and tannins or saponins (11% reduction) showing the greatest potential. We also suggest the most economically cost-effective mitigation measures, drawing on related work on the construction of marginal abatement cost curves for the sector.authorsversionPeer reviewe

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NIR light induced H2 evolution was realized by metal-free photocatalysis for the first time. The considerable H2 production at 808 nm and large promotion of the photocatalytic activity in both UV-Vis and Vis regions originated from the synergistic effect on spectral and electronic coupling of g-C3N4 nanosheets and carbon quantum dots.

In sliding friction, different energy dissipation channels have been proposed, including phonon and electron systems, plastic deformation, and crack formation. However, how energy is coupled into these channels is debated, and especially, the relevance of electronic dissipation remains elusive. Here, we present friction experiments of a single-asperity sliding on a high-Tc superconductor from 40 to 300 kelvin. Overall, friction decreases with temperature as generally expected for nanoscale energy dissipation. However, we also find a large peak around Tc. We model these results by a superposition of phononic and electronic friction, where the electronic energy dissipation vanishes below Tc. In particular, we find that the electronic friction constitutes a constant offset above Tc, which vanishes below Tc with a power law in agreement with Bardeen-Cooper-Schrieffer theory. While current point contact friction models usually neglect such friction contributions, our study shows that electronic and phononic friction contributions can be of equal size.

An open terbium-organic framework (UPC-11) based on a rigid tetracarboxylate ligand was successfully assembled, which exhibits excellent solvent-dependent photoluminescence (PL). Moreover, UPC-11 displays rapid and selective sensing of nitroaromatic compounds (NACs), especially for 4-nitrophenol (4-NP), which represents the first Tb MOF that can be used as fluorescence detection of 4-NP. N itroaromatic compounds (NACs) have become serious pollution sources of groundwater, soils, and other security applications due to their explosivity and high toxicity. 1,2 Hence, the convenient and high-efficiency detective technologies based on the NACs have received much attention from chemists. Although some traditional detective methods bear high selectivity such as metal detectors, gas chromatography, surface-enhanced Raman spectroscopy, electron capture detection, and cyclic voltammetry, 3−6 they are usually expensive, inconvenient, and not very good for manipulation. Therefore, new technologies need to be developed so that we may cheaply and rapidly complete detection. The fluorescencebased sensing materials have recently been considered as one of the most excellent and promising techniques in the detection of NACs, 7−9 because this kind of technique possesses several advantages such as high selectivity, simplicity, portability, and the ability to be applied in both solution and solid phases. 10−13 In the past decade, some oligomeric, polymeric, or nanoscale fluorescent materials have been prepared and used in the detection of NACs. 14−16 However, it is still a great challenge for chemists to develop novel fluorescent materials for the detection of NACs because it is not facile to introduce chromophores into the above-mentioned materials as fluorescence sensor.Metal−organic frameworks are a new class of crystalline materials, which are built from metal cations or clusters and organic ligands. 17−19 The fluorescent behavior of an MOF is highly dependent on the organic ligands and metal ion/cluster; thus, it is facile to construct fluorescent MOFs by using either organic ligands with chromophores or metal ions such as Zn 2+ , Cd 2+ , or Ln 3+ , or utilizing the combination of these two parts. 20−23 Li et al. pioneered the application of fluorescent MOFs on the detection of NACs. In 2009, they first reported a Zn MOF exhibiting fast and reversible detection of high explosives based on mixed ligands. 24 Following that, a series of fluorescent MOFs containing Zn 2+ and Cd 2+ ions were documented for the rapid fluorescence detection of NACs. 25−29 For example, Su et al. reported a two-dimensional Cd MOF that can recognize NACs with different numbers of nitro groups. 30 Moon et al. directly observed the interaction sites between NACs and the framework by a luminescent Libased MOF. 31 Surprisingly, fluorescence detection of NACs based on Ln MOFs was seldom explored, although Ln MOFs show characteristic emission properties and have been considered a class of popular luminescent materials that possess potential applications in bio...

Single-atom electrocatalysts (SACs) toward hydrogen evolution reaction (HER) have been extensively studied owing to their high mass activity and atom utilization. Although platinum (Pt) based SACs have been reported frequently, optimizing the metal-support interaction to achieve low valence state Pt species is still a challenge. Here, the carbon supported α-MoC 1−x nanoparticles are used to anchor zero-valent Pt single atoms (Pt SA /α-MoC 1−x @C) as electrocatalyst for pH-universal HER. The Pt SA /α-MoC 1−x @C with optimized Pt loading of 0.75 wt% shows a low overpotential (21, 12, and 36 mV at 10 mA cm -2 ) and high turnover frequencies (27.00, 31.98, and 21.39 H 2 s -1 at 100 mV) for HER under alkaline, acidic, and neutral electrolyte conditions. Experimental evidence combing density functional theory calculations confirm that the charge polarization leads to a zero-valence state of Pt single atom and further optimized the adsorption/desorption energy of intermediates, further accelerating the reaction dynamics for HER.

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