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Surface terminations of two-dimensional MXene (Ti3 C2 Tx ) considerably impact its physicochemical properties. Commonly used etching methods usually introduce -F surface terminations or metallic impurities in MXene. We present a new molten-salt-assisted electrochemical etching method to synthesize fluorine-free Ti3 C2 Cl2 . Using electrons as reaction agents, cathode reduction and anode etching can be spatially isolated; thus, no metallics are present in the Ti3 C2 Cl2 product. The surface terminations can be in situ modified from -Cl to -O and/or -S, which considerably shortens the modification steps and enriches the variety of surface terminations. The obtained -O-terminated Ti3 C2 Tx are excellent electrode materials for supercapacitors, exhibiting capacitances of 225 F g-1 at 1.0 Ag-1 , good rate performance (91.1 % at 10 Ag-1 ), and excellent capacitance retention (100 % after 10000 charge/discharge cycles at 10 Ag-1 ), which is superior to multi-layered Ti3 C2 Tx prepared by other etching methods.

Dry reforming of methane (DRM) is a feasible solution to cope with the reduction of greenhouse gas under the Paris Convention's obligations, given that it adds value by converting trivial gases of CO2 and CH4 simultaneously into useful syngas. However, conventional Ni catalyst undergoes deactivation due to carbon coking and particle agglomeration. Here we demonstrate for the first time a highly efficient and durable DRM catalyst of exsolved Co-Ni-Fe ternary alloy nanoparticles on the layered perovskite PrBaMn1.7Co0.1Ni0.2O5+d produced by topotactic exsolution. This readily allows the generation of a larger number of exsolved nanoparticles, enhancing catalytic activity above those of Ni monometallic and Co-Ni bimetallic particles. The enhancement is achieved by the optimal up-shift of the d-band center of Co-Ni-Fe than those of Co-Ni and Ni meaning easier charge donation to the adsorbate. Furthermore, the exsolved catalyst shows exceptional stability with the continuous DRM operation for about 350 hours.

Dry reforming of methane (DRM) has been emerging as a viable solution to achieving carbon neutrality enhanced by the Paris Agreement as it converts the greenhouse gases of CO

Monitoring and shielding of X-ray radiation are of paramount importance across diverse fields. However, they are frequently realized in separate protocols and a single material integrating both functions remained elusive. Herein, a hexanuclear cluster [Th

In selecting logistics service providers, the evaluation criteria can be easily prioritized and possibly interrelated with each other, and the assessment of alternatives under qualitative criteria is usually accomplished by more than one decision maker. A novel multicriteria decision-making approach with multihesitant fuzzy linguistic term elements (MHFLTEs) based on the Heronian mean (HM) and prioritized average operators can effectively deal with the problems inherent in such a scenario. Multihesitant fuzzy linguistic term sets (MHFLTSs) were proposed on the basis of multihesitant fuzzy sets (MHFSs) and hesitant fuzzy linguistic sets (HFLSs), where each MHFLTE can contain nonconsecutive and repeated linguistic terms. Using MHFLTEs, one decision maker can provide one or several consecutive linguistic terms in evaluating an alternative under one specific criterion, different decision makers’ evaluation values can be collected, and the frequency of a linguistic term in the evaluation information can accord with reality. This paper revises the basic operations and comparison method for MHFLTEs on the basis of the originals and defines some multihesitant fuzzy linguistic HM operators for MHFLTEs to deal with problems in which weight information cannot be accurately established for criteria, but their priorities can be provided in groups or without groups. Finally, the validity and effectiveness of the proposed approach are demonstrated through an illustration of a logistics outsourcing problem and a comparison analysis.

Actual stochastic multicriteria decision-making (MCDM) problems usually exhibit two forms of information loss: criteria value uncertainty and criteria weight uncertainty. In this paper, extended gray numbers (EGNs), integrated with discrete gray numbers and interval gray numbers are used to express the uncertainty of stochastic MCDM problems. Stochastic multicriteria acceptability analysis (SMAA) and ELECTRE III are combined to solve stochastic MCDM problems with uncertain weight information. First, the outranking relations on interval gray numbers and EGNs are defined. Then, a SMAA-ELECTRE model for dealing with gray stochastic MCDM problems is constructed. Finally, an illustrative example and two comparative analyses are provided to verify the feasibility and usability of the proposed approach. The proposed approach provides recommendations for alternatives based on uncertain preference information. It therefore contributes a new way to solve stochastic MCDM problems with uncertain, imprecise, and/or missing preference information.

In many practical problems, multiple alternatives are ranked with respect to related criteria, and the criteria's weights are usually unknown. In order to solve this kind of multicriteria decision making (MCDM) problem, this paper proposes an interactive MCDM approach based on an acronym in Portuguese of interactive and multicriteria decision-making (TODIM) method and nonlinear programming (NLP) with intuitionistic linguistic numbers (ILNs). First, by comparing the existing operations and comparison methods for ILNs, new operations and a new comparison method are defined based on linguistic scale functions to obtain rational results. Second, considering their linguistic terms, membership degrees, and nonmembership degrees as a whole, the generalized distance between ILNs is defined with an adjustable parameter. Third, the total ranking of alternatives is obtained using the proposed NLP-based TODIM approach based on the generalized ILN distance. Finally, an example of selecting hotels from a tourism website is presented to verify the validity and feasibility of the proposed approach. A comparison with existing methods is also conducted and analyzed.

The main purpose of this paper is to provide a multicriteria decision-making (MCDM) approach that applies the gray linguistic Bonferroni mean (BM) operator to address the situations where the criterion values take the form of gray linguistic numbers (GLNs) and the criterion weights are known. First, the related operations and comparison method for GLNs are provided. Subsequently, a BM operator and weighted BM operator of GLNs are developed. Then, based on the gray linguistic weighted BM operator, an MCDM approach is proposed. Finally, an illustrative example is given and a comparison analysis is conducted between the proposed approach and other existing methods to demonstrate the effectiveness and feasibility of the developed approach.

The N-methylation of amines with CO2 and H2 is an important step in the synthesis of bioactive compounds and chemical intermediates. The first heterogeneous Au catalyst is reported for this methylation reaction with good to excellent yields. The average turnover frequency (TOF) based on surface Au atoms is 45 h(-1) , which is the highest TOF value ever reported for the methylation of aniline with CO2 and H2 . Furthermore, the catalyst is tolerant toward a variety of amines, which includes aromatic, aliphatic, secondary, and primary amines. Preliminary mechanistic studies suggest that the N-alkyl formamide might be an intermediate in the N-methylation of amine process. Moreover, through a one-pot process, it is possible to convert primary amines, aldehydes, and CO2 into unsymmetrical tertiary amines with H2 as a reductant in the presence of the Au catalyst.

The production of methanol, an important fuel and chemical feedstock, from carbon dioxide is an important process for CO2 utilization. We describe herein a mild and efficient method for the indirect hydrogenation of carbon dioxide to methanol via a CO2-derived formate ester intermediate by using a simple heterogeneous catalyst system comprising Cu highly dispersed in an alumina matrix under solvent-free conditions. This catalyst is also effective for the hydrogenation of other formate esters, such as ethyl formate, propyl formate, and butyl formate.

Program of International ST Cooperation [2014DFG60230]; National Basic Research Program of China [2013CB933104]; National Natural Science Foundation of China [21303246, 11275258, 91127001]

The reductive methylation of cyclic amines (I) and (IV) as well as secondary amines (VI) with carbon dioxide proceeds readily in the presence of gold nanoparticles supported on γ-alumina as a heterogeneous catalyst.

The ligand-free Ir/TiO2 nanocluster catalyst allows for the synthesis of various quinolines (III) under mild conditions.

The introduction of a mesityl (Mes; 2,4,6-Me3C6H2) ligand to a Ge9 polyanion is accomplished by the reaction of [Ge9]4– solutions with Ag4Mes4. The crystal structure investigation of its [K([2.2.2]crypt)] salt ([2.2.2]crypt: 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) shows that [Ge9Mes]3– comprises one exo-bonded aryl ligand in accordance with the 1H NMR spectroscopic data. The formation of mono-, bis-, and tris-substituted Zintl Ions [Ge9Rn](4–n)– (n = 1, 2, and 3; R = CHCH2) is investigated by 1H NMR spectroscopy. The mono- and bis-vinylated Ge9 clusters, [Ge9(CHCH2)]3– and [Ge9(CHCH2)2]2–, were obtained by the reaction of K4Ge9 with Me3SiC≡CSiMe3 in ethylenediamine. In the presence of [18]crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) and K(C5H5) crystals containing both cluster species were isolated and structurally characterized as[K([18]crown-6)]2{(η5-C5H5)[K([18]crown-6)]2}[Ge9(CHCH2)]and [K([18]crown-6)]{(η5-C5H5)[K([18]crown-6)]2}[Ge9(CHCH2)2], respectively. 1H NMR experiments hint for the tris-vinylated cluster [Ge9(CHCH2)3]–.

Inorganic pentaprismane: The unusual structure of the anion [Co@Ge(10)](3-), which was obtained by the reaction of K(4)Ge(9) with [Co(C(8)H(12))(C(8)H(13))] in ethylenediamine, raises questions about chemical bonding in the anion. The Zintl ion cluster has virtual D(5h) symmetry and is a unique example of a ligand-free cluster that is not a deltahedron. The delocalized chemical bonding is represented in the picture by one of the bonding orbitals of the anion.

The reactions of the Zintl phase K2Cs2Sn9 with elemental tellurium and selenium in ethylenediamine have been investigated. From the reaction of K2Cs2Sn9 with elemental tellurium [K-(2,2,2-crypt)]4Te6Te4 (2) and [K-(2,2,2-crypt)]2Sn2Te3 (3) were obtained, whereas the reaction of K2Cs2Sn9 with elemental selenium led to the formation of [K-(2,2,2-crypt)]2Sn(Se4)3 (4) and [K-(2,2,2-crypt)]2Cs2Sn2Se6·2en (5)1). Compounds 2, 4, 5 have been characterized by single crystal X-ray structure determination.

Methanol is a sustainable source of liquid fuels and one of the most useful organic chemicals. To date, most of the work in this area has focused on the direct hydrogenation of CO2 to methanol. However, this process requires high operating temperatures (200-250 °C), which limits the theoretical yield of methanol. Thus, it is desirable to find a new strategy for the efficient conversion of CO2 to methanol at relatively low reaction temperatures. This Minireview seeks to outline the recent advances on the indirect hydrogenation of CO2 to methanol. Much emphasis is placed on discussing specific systems, including hydrogenation of CO2 derivatives (organic carbonates, carbamates, formates, cyclic carbonates, etc.) and cascade reactions, with the aim of critically highlighting both the achievements and remaining challenges associated with this field.

The ligand-free Ir/TiO2 nanocluster catalyst allows for the synthesis of various quinolines (III) under mild conditions.

The cluster anion of title is obtained from the Zintl anion Sn94- by an oxidative coupling reaction.

A new hepatoprotective lactam (+)-(3R,4S,5R,7S)-neoclausenamide 1 isolated from the leaves of Chinese folk medicine Clausena lansium(Lour.) Skeel, has been readily synthesized from methyl (2R,3S)-2,3-dihydroxy-3-phenylpropanoate in 22.0% overall yield.

Aromatic and alkyl alcohols were oxidized to the corresponding aldehydes or ketones at room temperature with high conversion and selectivity using Oxone(superscript ®) (2KHSO5•KHSO4•K2SO4) as oxidant catalyzed by ruthenium complex Quin-Ru-Quin (where Quin=8-hydroxyquinoline). The reaction time is very short and the preparation of complex is simple.