Isomorphous Substitution of Organic Cage Crystal by Pd Nanoclusters for Selective Hydrogenation.

For supporting active metal, the cavity confinement and mass transfer facilitation lie not in one sack, a trade-off between high activity and good stability of the catalyst is present. Porous organic cages (POCs) are expected to break the trade-off when metal particles are properly loaded. Herein, three organic cages (CC3, RCC3, and FT-RCC3) are employed to support Pd nanoclusters for catalytic hydrogenation. Subnanometer Pd clusters locate differently in different cage frameworks by using the same reverse double-solvents approach. Compared with those encapsulated in the intrinsic cavity of RCC3 and anchored on the outer surface of CC3, the Pd nanoclusters orderly assembled in FT-RCC3 crystal via isomorphous substitution exhibit superior activity, high selectivity, and good stability for semi-hydrogenation of phenylacetylene. Isomorphous substitution of FT-RCC3 crystal by Pd nanoclusters is originated from high crystallization capacity of FT-RCC3 and specific interaction of each Pd nanocluster with four cage windows. Both confinement function and H2 accumulation capacity of FT-RCC3 are fully utilized to support active Pd nanoclusters for efficient selective hydrogenation. The present results provide a new perspective to the heterogeneous catalysis field in terms of crystalizing metal nanoclusters in POC framework and outside the cage for making the best use of both parts.

Highly Dispersed Mn-Doped Ceria Supported on N-Doped Carbon Nanotubes for Enhanced Oxygen Reduction Reaction.

The weak adsorption of oxygen on transition metal oxide catalysts limits the improvement of their electrocatalytic oxygen reduction reaction (ORR) performance. Herein, a dopamine-assisted method is developed to prepare Mn-doped ceria supported on nitrogen-doped carbon nanotubes (Mn-Ce-NCNTs). The morphology, dispersion of Mn-doped ceria, composition, and oxygen vacancies of the as-prepared catalysts were analyzed using various technologies. The results show that Mn-doped ceria was formed and highly dispersed on NCNTs, on which oxygen vacancies are abundant. The as-prepared Mn-Ce-NCNTs exhibit a high ORR performance, on which the average electron transfer number is 3.86 and the current density is 24.4% higher than that of commercial 20 wt % Pt/C. The peak power density of Mn-Ce-NCNTs is 68.1 mW cm-2 at the current density of 138.9 mA cm-2 for a Zn-air battery, which is close to that of 20 wt % Pt/C (69.4 mW cm-2 at 106.1 mA cm-2). Density functional theory (DFT) calculations show that the oxygen vacancy formation energies of Mn-doped CeO2(111) and pure CeO2(111) are -0.55 and 2.14 eV, respectively. Meanwhile, compared with undoped CeO2(111) (-0.02 eV), Mn-doped CeO2(111) easily adsorbs oxygen with the oxygen adsorption energy of only -0.68 eV. This work provides insights into the synergetic effect of Mn-doped ceria for facilitating oxygen adsorption and enhancing ORR performance.

China's green data center development:Policies and carbon reduction technology path.

Data center is a very important infrastructure to support the development of information technology, and its development and increment are very remarkable. However, with the rapid and large-scale development of data centers, the problem of energy consumption turns to be also very prominent. Under the background of global carbon peak and carbon neutrality, developing green and low-carbon data centers has become an inevitable trend. This paper reviews and analyzes the policies and their roles in promoting China's green development of data centers in the past 10 years, summarizes the current situation of the implementation of green data center projects in China and gives the changes of PUE limits of data centers under the policy constraints. Application of green technologies is an important measure for energy-saving and low-carbon development of data centers, so encouraging innovation and application of green technologies in data center is also a priority task in relevant policies. This paper points out the green and low-carbon technology system of data centers, further summarizes energy-saving and carbon-reducing technologies in IT equipment, cooling system, power supply and distribution system, lighting, intelligent operation and maintenance, and provides an outlook on the future green development of data centers.

Understanding deep dehydrogenation and cracking of n-butane on Ni(111) by a DFT study.

Steam reforming is a main industrial process for hydrogen production. In particular, with the carbon chain increasing to n-butane, a main component in liquefied petroleum gas (LPG) and shale oil gas, chemically different C-C bonds ((C-C)α,ß and (C-C)ß,ß') will be involved in cleavages. In addition, understanding the role of catalysis in these pathways is critical toward the advancement in technology, yet is largely lacking. As such, we have performed density functional theory (DFT) calculations to study the two possible C-C cleavage pathways of n-butane on Ni(111), i.e., the (C-C)α,ß cleavage from the n-butane deep dehydrogenation product of 1-butyne, and the (C-C)ß,ß' cleavage from 2-butyne. The results indicate that these two different pathways have distinct dehydrogenations to butyne, and that Ni is suitable for the deep dehydrogenation. The C-C cleavage in both pathways serves as the rate-determining step with a higher energy barrier than that for the preceding C-H bond cleavage. In addition, the 1-butyne pathway was found to be more favorable than that of 2-butyne in thermodynamics and kinetics. Our results provide insights into the alkane dehydrogenation and cracking of long-chain hydrocarbons on Ni-based catalysts.

Ruthenium(II)-Catalyzed Asymmetric Inert C-H Bond Activation Assisted by a Chiral Transient Directing Group.

A ruthenium(II)-catalyzed asymmetric intramolecular hydroarylation assisted by a chiral transient directing group has been developed. A series of 2,3-dihydrobenzofurans bearing chiral all-carbon quaternary stereocenters have been prepared in remarkably high yields (up to 98 %) and enantioselectivities (up to >99 % ee). By this methodology, a novel asymmetric total synthesis of CB2 receptor agonist MDA7 has been successfully developed.

Chiral Bicyclo[2.2.2]octane-Fused CpRh Complexes: Synthesis and Potential Use in Asymmetric C-H Activation.

A new class of chiral cyclopentadienyl rhodium(I) complexes (CpRhI ) bearing C2 -symmetric chiral bridged-ring-fused Cp ligands was prepared. The complexes were successfully applied to the asymmetric C-H activation reaction of N-methoxybenzamides with quinones, affording a series of chiral hydrophenanthridinones in up to 82 % yield with up to 99 % ee. Interestingly, structure analysis reveals that the side wall of the optimal chiral CpRhI catalyst is vertically more extended, horizontally less extended, and closer to the metal center in comparison with the classic binaphthyl and spirobiindanyl CpRhI complexes, and may thus account for its superior catalytic performance.

Coupling of capillary electrophoresis with electrospray ionization multiplexing ion mobility spectrometry.

In this work, ion mobility spectrometry (IMS) function as a detector and another dimension of separation was coupled with CE to achieve two-dimensional separation. To improve the performance of hyphenated CE-IMS instrument, electrospray ionization correlation ion mobility spectrometry is evaluated and compared with traditional signal averaging data acquisition method using tetraalkylammonium bromide compounds. The effect of various parameters on the separation including sample introduction, sheath fluid of CE and drift gas, data acquisition method of IMS were investigated. The experimental result shows that the optimal conditions are as follows: hydrodynamic sample injection method, the electrophoresis voltage is 10 kilo volts, 5 mmol/L ammonium acetate buffer solution containing 80% acetonitrile as both the background electrolyte and the electrospray ionization sheath fluid, the ESI liquid flow rate is 4.5 µL/min, the drift voltage is 10.5 kilo volts, the drift gas temperature is 383 K and the drift gas flow rate is 300 mL/min. Under the above conditions, the mixture standards of seven tetraalkylammoniums can be completely separated within 10 min both by CE and IMS. The linear range was 5-250 µg/mL, with LOD of 0.152, 0.204, 0.277, 0.382, 0.466, 0.623 and 0.892 µg/mL, respectively. Compared with traditional capillary electrophoresis detection methods, the developed CE-ESI-IMS method not only provide two sets of qualitative parameters including electrophoresis migration time and ion drift time, ion mobility spectrometer can also provide an additional dimension of separation and could apply to the detection ultra-violet transparent compounds or none fluorescent compounds.

Introducing the Chiral Transient Directing Group Strategy to Rhodium(III)-Catalyzed Asymmetric C-H Activation.

The chiral transient directing group (TDG) strategy has been successfully introduced to the rhodium(III)-catalyzed asymmetric C-H activation. In the presence of a catalytic amount of a chiral amine and an achiral rhodium catalyst, various chiral phthalides were synthesized from simple aldehydes with high chemoselectivity, regioselectivity, and enantioselectivity (53 examples, up to 73 % yield and >99 % ee). It is noteworthy that the chiral induction model is different from the previously reported chiral TDG system using amino acid derivatives and palladium salts. The imino group generated in situ from chiral amine and aldehyde acts as the monodentate TDG to promote the C-H activation, stereoselectively generating the chiral rhodacycle bearing a chiral metal center. Moreover, the stereogenic center of the product is created and stereocontrolled during the Grignard-type addition of the C-Rh bond to aldehyde, rather than during the C-H activation step.

Comparison Study on the Prediction of Multiple Molecular Properties by Various Neural Networks.

Various neural networks, including a single layer neural network (SLNN), a deep neural network (DNN) with multilayers, and a convolution neural network (CNN) have been developed and investigated to predict multiple molecular properties simultaneously. The data set of this work contains∼134 kilo molecules and their 15 properties (including rotational constant A, B, and C, dipole moment, isotropic polarizability, energy of HOMO, energy of LUMO, HOMO-LUMO gap energy, electronic spatial extent, zero point vibrational energy, internal energy at 0 K, internal energy at 298.15 K, enthalpy at 298.15 K, free energy at 298.15 K, and heat capacity at 298.15 K) at the hybrid density functional theory (DFT) level from the QM9 database. Coulomb matrix (CM) converted from the database representing every molecule uniquely and its eigenvalue are respectively used as the input of machine learning. The accuracies of predictions have been compared among SLNN, DNN and CNN by analyzing their mean absolute errors (MAEs). Using eigenvalues as input, both SLNN and DNN can give higher accuracy for the prediction of specific energy properties ( U0, U, H, and G). For the prediction of all 15 molecular properties at a time, DNN with a 3-layers network exhibits the best results using the full CM as input. The number of layers in DNN play a key role in the prediction of multiple molecular properties simultaneously. This work may provide possibility and guidance for the selection of different neural networks and input data forms for prediction and validation of multiple parameters according to different needs.

Interfacial Nanostructure and Asymmetric Electrowetting of Ionic Liquids.

In this work, the interfacial nanostructure and electrowetting of ionic liquids having the same 1-ethyl-3-methylimidazolium cation ([EMIm]+) but different anions such as bis(trifluoromethylsulfonyl)imide (TFSI-), trifluoromethylsulfonate (TfO-), methylsulfonate (OMs-), acetate (OAc-), bis(fluorosulfonyl)imide (FSI-), dicyanamide (DCA-), and tris(pentafluorethyl)trifluorphosphat (FAP-) on bare metallic electrodes were investigated. In the investigated voltammetric potential regime, the contact angle versus voltage curve is asymmetric with respect to surface polarity. The electrowetting of the ILs occurs at negative potentials but does not occur at positive potentials. In situ atomic force microscopy (AFM) shows that the IL adopts a multilayered structure at the solid/IL interface, and a cation-rich layer is present in the innermost layer during cathodic polarization. The cations can change their orientation and propagate ahead of the three-phase contact line by diffusion, leading to further spreading on the negatively charged surface. The formation of such a surface layer is also evidenced by X-ray photoelectron spectroscopy. Such a surface diffusion mechanism does not occur during anodic polarization, where anions are enriched. In addition, the influence of substrate, water, and dissolved zinc salts on the electrowetting of ILs was studied. Our findings provide valuable insights for the interfacial nanostructure and the electrowetting of ILs.

Tuning the electronic environment of zinc ions with a ligand for dendrite-free zinc deposition in an ionic liquid.

In this work, we report on the influence of an organic ligand on the electrodeposition of Zn from an ionic liquid (IL) electrolyte. Zinc oxide was first dissolved in a protic IL. By introducing a 2-methylimidazole (2-MIm) ligand, the electronic environment of zinc ions, Zn(ii) complexes and the structure of the IL are considerably altered, as verified by both X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Due to the electron donation effect of the ligand, the zinc ions become less positively charged and exhibit a lower binding energy by -0.5 eV, compared to its absence. The atomic force microscopy (AFM) results show that a higher push-through force is required to rupture the interfacial layers in the presence of the ligand compared to its absence. The ligand can interact with both the cation and the anion of the IL via hydrogen bonds, forming compact layers on the surface, which also has a strong influence on the electrochemical performance. The cyclic voltammograms show reduction peaks at -1.4 V in all cases, but the current density decreases as the concentration of 2-MIm increases. Dendritic zinc deposits were obtained in 1.5 mol L-1 ZnO/[EIm]TfO, while dendrite-free zinc structures were obtained in the presence of 1.5 mol L-1 2-MIm.

Density Functional Theory Analysis of Anthraquinone Derivative Hydrogenation over Palladium Catalyst.

A density functional theory (DFT) analysis was conducted on the hydrogenation of 2-alkyl-anthraquinone (AQ), including 2-ethyl-9,10-anthraquinone (eAQ) and 2-ethyl-5,6,7,8-tetrahydro-9,10-anthraquinone (H4 eAQ), to the corresponding anthrahydroquinone (AQH2 ) over a Pd6 H2 cluster. Hydrogenation of H4 eAQ is suggested to be more favorable than that of eAQ owing to a higher adsorption energy of the reactant (H4 eAQ), lower barrier of activation energy, and smaller desorption energy of the target product (2-ethyl-5,6,7,8-tetrahydro-9,10-anthrahydroquinone, H4 eAQH2 ). For the most probable reaction routes, the energy barrier of the second hydrogenation step of AQ is circa 8 kcal mol-1 higher than that of the first step. Electron transfer of these processes were systematically investigated. Facile electron transfer from Pd6 H2 cluster to AQ/AQH intermediate favors the hydrogenation of C=O. The electron delocalization over the boundary aromatic ring of AQ/AQH intermediate and the electron-withdrawing effect of C=O are responsible for the electron transfer. In addition, a pathway of the electron transfer is proposed for the adsorption and subsequent hydrogenation of AQ on the surface of Pd6 H2 cluster. The electron transfers from the abstracted H atom (reactive H) to a neighbor Pd atom (PdH ), and finally goes to the carbonyl group through the C4 atom of AQ aromatic ring (C4 ).

Surface-Engineered Polydopamine Particles as an Efficient Support for Catalytic Applications.

Mussel-inspired polydopamine (PDA) particles with the size of ∼270 nm are used as a support of palladium (Pd) nanoparticles (NPs) for catalyst preparation. The surface morphology of the PDA particle has been modified via corrosion of CF3COOH. Surface chemistry of the obtained PDA particle has been engineered by the formation of a carboxylic acid-terminated alkanethiol monolayer. The obtained self-assembled monolayer-modified PDA (SAM-PDA) particles are used to load Pd NPs by simply adding H2PdCl4 solution to a suspension of SAM-PDA particles at room temperature. Transmission electron microscopy, energy-dispersive X-ray mapping, dynamic light scattering, X-ray diffraction, X-ray photoelectron spectroscopy, UV-vis, and Fourier transform infrared are used to characterize the catalyst and to investigate the process. Uniform Pd NPs (2-3 nm) have been well-dispersed on the SAM-PDA particles via controllable surface engineering. Surface charges and interactions with a metal ion are regulated by the monolayer of carboxylic acids. The surface chemistry of PDA particles has been finely engineered for efficient loading of noble metal NPs. The obtained Pd/SAM-PDA catalyst has shown greatly increased activity and good reusability compared with Pd/PDA in the reduction of 4-nitrophenol (4-NP) by sodium borohydride or H2. The kinetic data of 4-NP hydrogenation catalyzed by Pd/SAM-PDA are fitted to a Langmuir-Hinshelwood (L-H) model, and the calculated apparent activation energy of this process is 40.77 kJ mol-1.

The impact of sustainable development planning on urban ecological resilience in resource-based cities: evidence from China.

Enhancing resource cities' resilience and advancing their sustainable development are imperatives, particularly in light of the "dual-carbon" agenda. Double-difference and spatial double-difference models are developed based on the panel data of 281 Chinese cities from 2005 to 2020 to investigate the effects of implementing the National Plan for the Sustainable Development of Resource-Based Cities on the level of ecological resilience in Chinese cities. This paper found that the National Sustainable Development Plan for Resource-Based Cities significantly improves the ecological resilience level of Chinese cities, and the findings are robust. The impacts of implementing the Plan on the ecological resilience of cities of different growth types, regions, and resource types are heterogeneous. Further study finds a spatial spillover effect of implementing the Plan on the ecological resilience of cities, which can improve the ecological resilience level of neighboring cities through spillover effects while improving the ecological resilience level of cities in the region. Based on these new findings, this study provides some policy implications for better advancing sustainable urban development.

Boosting photo-thermal co-catalysis CO2 methanation by tuning interface electron transfer via Mott-Schottky heterojunction effect.

Photo-thermal co-catalytic reduction of CO2 to synthesize value-added chemicals presents a promising approach to addressing environmental issues. Nevertheless, traditional catalysts exhibit low light utilization efficiency, leading to the generation of a reduced number of electron-hole pairs and rapid recombination, thereby limiting catalytic performance enhancement. Herein, a Mott-Schottky heterojunction catalyst was developed by incorporating nitrogen-doped carbon coated TiO2 supported nickel (Ni) nanometallic particles (Ni/x-TiO2@NC). The optimal Ni/0.5-TiO2@NC sample displayed a conversion rate of 71.6 % and a methane (CH4) production rate of 65.3 mmol/(gcat·h) during photo-thermal co-catalytic CO2 methanation under full-spectrum illumination, with a CH4 selectivity exceeding 99.6 %. The catalyst demonstrates good stability as it shows no decay after two reaction cycles. The Mott-Schottky heterojunction catalysts display excellent efficiency in separating photo-generated electron-hole pairs and elevate the catalysts' temperature, thus accelerating the reaction rate. The in-situ experiments revealed that light-induced electron transfer effectively facilitates H2 dissociation and enhances surface defects, thereby promoting CO2 adsorption. This study introduces a novel approach for developing photo-thermal catalysts for CO2 reduction, aiming to enhance solar energy utilization and facilitate interface electron transfer.

Silver-zwitterion organic-inorganic nanocomposite with antimicrobial and antiadhesive capabilities.

In this work, we demonstrate a convenient, efficient, and environmentally benign strategy to achieving antimicrobial and antiadhesive purposes using a silver-zwitterion nanocomposite. The synthesis of the nanocomposite relies on loading zwitterionic polymer brushes with Ag(+) precursor ions, followed by their in situ reduction to Ag nanoparticle by ultraviolet (UV) irradiation. Both poly(sulfobetaine methacrylate) (pSBMA) and poly(carboxybetaine methacrylate) (pCBMA) have been studied as matrices for the embedding of silver. Well-dispersed silver nanoparticles are embedded into pCBMA matrices. The obtained pCBMA-silver hybrid (CB-Ag) is capable of killing bacteria upon contact and releasing dead bacteria under wet conditions. Results suggest the feasibility of using this nanocomposite system as a robust and reliable antimicrobial and antiadhesive platform for the prevention of microbial colonization.

Has pilot zones policy for green finance reform and innovations improved the level of green financial development and environmental quality?

This study uses the green finance reform and innovation pilot zone policy approved by the State Council in 2017 as a quasi-natural experiment to explore whether the implementation of the policy has improved the level of green finance development and environmental quality in Chinese cities at the prefecture level and above. The results show that the green financial reform and innovation pilot zone policy can significantly improve the level of regional green financial development and environmental quality, and the results are robust. Further heterogeneity analysis finds that the green financial reform and innovation pilot zone policy have heterogeneous effects on the level of green financial development and environmental quality in different regions, sizes, environmental regulation intensity, financial development levels, and cities of different administrative levels. Based on this conclusion, suggestions are made that the scope should be further expanded and green finance policies should be formulated differently.

Fabrication of superhydrophilic porous carbon materials through a porogen-free method: Surface and structure modification promoting the two-electron oxygen reduction activity.

HYPOTHESIS: Electrochemical manufacture of H2O2 through the two-electron oxygen reduction reaction (2e- ORR), providing prospects of the distributed production of H2O2 in remote regions, is considered a promising alternative to the energy-intensive anthraquinone oxidation process. EXPERIMENTS: In this study, one glucose-derived oxygen-enriched porous carbon material (labeled as HGC500) is developed through a porogen-free strategy integrating structural and active site modification. FINDINGS: The superhydrophilic surface and porous structure together promote the mass transfer of reactants and accessibility of active sites in the aqueous reaction, while the abundant CO species (e.g., aldehyde groups) are taken for the main active site to facilitate the 2e- ORR catalytic process. Benefiting from the above merits, the obtained HGC500 possesses superior performance with a selectivity of 92 % and mass activity of 43.6 A gcat-1 at 0.65 V (vs. RHE). Besides, the HGC500 can operate steadily for 12 h with the accumulation of H2O2 reaching up to 4090±71 ppm and a Faradic efficiency of 95 %. The H2O2 generated from the electrocatalytic process in 3 h can degrade a variety of organic pollutants (10 ppm) in 4-20 min, displaying the potential in practical applications.

Effectively removing the homodimer in bispecific antibodies by weak partitioning mode of anion exchange chromatography.

Small amounts of by-products are nevertheless created during the recombinant production of IgG-like bispecific antibodies due to imbalanced chain expression and improper chain pairing, despite the employment of molecular strategy techniques to promote accurate pairing. Among them, homodimers represent the species that are more difficult to remove due to their physical and chemical properties being similar to the target antibody. Homodimer by-products are always produced even though various technologies can significantly increase the expression of heterodimers, so a robust purification process to recover high-purity heterodimers is required. Most of the chromatography methods commonly adopt the bind-and-elute mode or two-step to separate homodimers, which has numerous drawbacks such as prolonged process times and limited dynamic binding capacity. Flow-through mode of anion exchange is a frequently-used polishing step for antibodies, but it is typically regarded as being more effective for host-cell protein or host-cell DNA removal rather than other product-related impurities such as homodimers and aggregates. This paper demonstrated that single-step anion exchange chromatography allows high capacity and effective clearance of the homodimer byproduct to be simultaneously achieved, suggesting that weak partitioning was a better polishing strategy for achieving a high level of heterodimer purity. And robust operation range of anion exchange chromatography steps for homodimer removal was also developed by leveraging the design of experiments.

State-of-the-Art Advancements in Photocatalytic Hydrogenation: Reaction Mechanism and Recent Progress in Metal-Organic Framework (MOF)-Based Catalysts.

Photocatalytic hydrogenation provides an effective alternative way for the synthesis of industrial chemicals to meet the economic and environment expectations. Especially, over the past few years, metal-organic frameworks (MOFs), featured with tunable structure, porosity, and crystallinity, have been significantly developed as many high-performance catalysts in the field of photocatalysis. In this review, the background and development of photocatalytic hydrogenation are systemically summarized. In particular, the comparison between photocatalysis and thermal catalysis, and the fundamental understanding of photohydrogenation, including reaction pathways, reducing species, regulation of selectivity, and critical parameters of light, are proposed. Moreover, this review highlights the advantages of MOFs-based photocatalysts in the area of photohydrogenation. Typical effective strategies for modifying MOFs-based composites to produce their advantages are concluded. The recent progress in the application of various types of MOFs-based photocatalysts for photohydrogenation of unsaturated organic chemicals and carbon dioxide (CO2 ) is summarized and discussed in detail. Finally, a brief conclusion and personal perspective on current challenges and future developments of photocatalytic hydrogenation processes and MOFs-based photocatalysts are also highlighted.