Ammoniated-driven green synthesis of charged polyoxometalate supported ionic liquids for exceptional heavy metal remediation in actual industrial wastewater.

Reducing toxic metal concentrations to extremely low levels has long posed a challenge. Polyoxometalate supported ionic liquids (POM-SILs) offer significant potential for advanced water remediation, but their application is limited by complex preparation, toxic solvents, and poor stability due to leaching, compromising sustainability. We introduced a sustainable approach for selectively removing Pb(II) in complex electroplating wastewater using charged POM-SILs composite, synthesized by directly grafting lacunary Keggin ions ([α-SiWO], SiW) onto charged ammoniated polystyrene via a straightforward, solvent-free process.

Biphasic 1T/2H-MoS Nanosheets In Situ Vertically Anchored on Reduced Graphene Oxide via Covalent Coupling of the Mo-O-C Bond for Enhanced Electrocatalytic Hydrogen Evolution.

Transition-metal dichalcogenides (TMDs) have recently emerged as promising electrocatalysts for the hydrogen evolution reaction owing to their tunable electronic properties. However, TMDs still encounter inherent limitations, including insufficient active sites, poor conductivity, and instability; thus, their performance breakthrough mainly depends on structural optimization in hybridization with a conductive matrix and phase modulation. Herein, a 1T/2H-MoS/rGO hybrid was rationally fabricated, which is characterized by biphasic 1T/2H-MoS nanosheets in situ vertically anchored on reduced graphene oxide (rGO) with strong C-O-Mo covalent coupling.

Role of Dy 4electrons on magnetic coupling and reorientation in DyFeO.

Spin reorientation transition is an ubiquitous phenomenon observed in magnetic rare earth orthferrites RFeO, which has garnered significant attention in recent years due to its potential applications in spintronics or magnetoelectric devices. Although a plenty of experimental works suggest that the magnetic interaction between Rand Fespins is at the heart of the spin reorientation, but a direct and conclusive theoretical support has been lacking thus far, primarily due to the challenging nature of handling R 4electrons. In this paper, we explored DyFeOas an example by means of comprehensive first principles calculations, and compared two different approaches, where the Dy 4electrons were treated separately as core or valence states, aiming to elucidate the role of Dy 4electrons, particularly in the context of the spin reorientation transition.

Pressure-induced structural and magnetic ordering transitions in the - square lattice antiferromagnets AMoOPOCl (A = K, Rb).

By means of density functional theory calculations taking into account electronic correlation and van der Waals force, we conducted comprehensive studies of the electronic and magnetic properties, as well as structural and magnetic ordering evolution under pressure of the square lattice antiferromagnets AMoOPOCl (A = K, Rb) containing Mo ions with , theoretically predicted as the potential candidates for achieving quantum phases, existing in the boundary regimes for square lattice magnets. Our results indicate that the columnar antiferromagnetic ordering, experimentally determined, is the magnetic ground state of the ambient 4/ phase, stabilized by the predominant antiferromagnetic next nearest neighbor interaction in the diagonal directions of the square lattice, regardless of the effective Hubbard amendment values. More importantly, the 4/ phase, involving the mutual twisting of the MoOCl and PO polyhedra, satisfactorily reproduces the experimentally observed structural transition and the subsequent magnetic ordering transition from columnar antiferromagnetic ordering to Néel antiferromagnetic one, identified to be the appropriate high pressure structure.

Homocoupling of benzyl pyridyl ethers visible light-mediated deoxygenation.

The photocatalytic coupling of ethers is uncommon because of the challenges in breaking C-O bonds and low selectivity. Herein, we report a visible light-mediated deoxygenation homocoupling of benzyl pyridyl ethers their pyridium salts. This approach enables C(sp)-O bond homolysis under mild conditions.

Role of V-V dimerization on electronic and magnetic properties of ilmenite-type CoVO.

Structural, electronic and magnetic properties of ilmenite-type CoVOhave been explored via the generalized gradient approximation + effective Hubbardcorrection, in the framework of density functional theory. Our results indicate that high temperature rhombohedralR3-phase is metallic with oxidation states and electronic configurations Co(t2g↑3eg↑2t2g↓2eg↓0), V(t2g↑1eg↑0t2g↓0eg↓0), respectively, while low temperature triclinicP1-phase, induced from spin-Peierls transition in the V-V dimerization manner, is insulating, maintaining charge and electronic states unchanged. Furthermore, the A-type antiferromagnetic ordering, where the ferromagnetic honeycomb layers are anti-aligned along the stacking axis, is identified to be the magnetic ground state for the low temperature phase, in nice agreement with experimental findings, analogous to CoTiO.

High-nuclearity and thiol protected core-shell [Cu(S-Adm)]: distorted octahedra fixed to Cu core strong cuprophilic interactions.

Atomically precise nanoclusters have a critical role in understanding the structure-property relationships at the atomic level. Copper nanoclusters have attracted considerable attention, but the synthesis is limited because of susceptibility to oxidation. Herein, we developed a reduction speed controlling method to synthesize [Cu(S-Adm)] (HS-Adm: 1-Adamantanethiol) nanocluster and reveal the key steps in the nucleation process.

Synthesis of Unnatural α-Amino Acids from (Pyridin-2-yl) Carbamate via CIPE-Induced Carbonyl Migration.

Synthetic methods of unnatural α-amino acids have always been the focus of extensive research due to their significant bioactivities. However, convenient transition-metal-free catalyzed methods are still in demand. Herein, we report a novel strategy for the construction of an unnatural α-amino acid skeleton via intramolecular rearrangement of carbamates, which are readily available from amines and their common protecting groups.

Electronic and Magnetic Properties of Spin-Orbit-Entangled Honeycomb Lattice Iridates MIrO (M = Cd, Zn, and Mg).

By means of density functional theory calculations with the inclusion of spin-orbit coupling, we present a comprehensive investigation of the structural, electronic, and magnetic properties of the novel series of ilmenite-type honeycomb lattice iridates MIrO (M = Cd, Zn, and Mg), the potential candidates for realizing the quantum spin liquid. Our findings are as follows: (i) the structural relaxations could not properly capture the abnormal thin two-dimensional honeycomb IrO layers in CdIrO, making the experimentally proposed crystal structure questionable. Furthermore, the calculations within the experimental structure could not correctly determine the magnetic ground state; however, the results within the optimized one rectify this scenario and provide a precise and reasonable description of its electronic and magnetic properties, which is in good agreement with the experimental observations and that of Zn and Mg analogues.

Finding Key Factors for Efficient Water and Methanol Activation at Metals, Oxides, MXenes, and Metal/Oxide Interfaces.

Activating water and methanol is crucial in numerous catalytic, electrocatalytic, and photocatalytic reactions. Despite extensive research, the optimal active sites for water/methanol activation are yet to be unequivocally elucidated. Here, we combine transition-state searches and electronic charge analyses on various structurally different materials to identify two features of favorable O-H bond cleavage in HO, CHOH, and hydroxyl: (1) low barriers appear when the charge of H moieties remains approximately constant during the dissociation process, as observed on metal oxides, MXenes, and metal/oxide interfaces.

Synthesis of -Dimethylcyclopentane-Fused Arenes with Various Topologies via TBD-Mediated Dehydro-Diels-Alder Reaction.

The development of efficient methods for the synthesis of substituted polycyclic arenes with various topologies is in high demand due to their excellent electrical and optical properties. In this work, a series of -dimethylcyclopentane-fused arenes with more than ten topologies were synthesized via a 1,5,7-Triazabicyclo[4.4.

[AuAg(SR)S] Nanocluster: Open Shell Structure and High Faradaic Efficiency in Electrochemical Reduction of CO to CO.

For atomically precise metal nanoclusters, distinctive molecular architectures and promising applications are urgently required to be intensively explored. Herein, we have first reported the open shell structure of the [AuAg(S-Adm)S] nanocluster and its application in the electrochemical reduction of CO. The X-ray crystal structure of the AuAg nanocluster is composed of a AuAg icosahedron kernel and a Ag(SR)S open shell.

Magnetic Interactions in ZnMnO: Active Role of Zn 3d Orbitals, in Comparison with MgMnO.

The ilmenite-type MgMnO and ZnMnO with honeycomb Mn layers exhibit distinctive magnetic ground states. In experiments, MgMnO exhibits a Néel antiferromagnetic alignment, in which both nearest-neighbor (NN) and next-nearest-neighbor (NNN) exchange interactions are antiferromagnetic, while ZnMnO has zigzag antiferromagnetic ordering with NN ferromagnetic and NNN antiferromagnetic coupling. On the basis of band structure calculations, we explain the deviation of NN exchange coupling from antiferromagnetic (MgMnO) to ferromagnetic (ZnMnO) as originating from the intensive hybridization between the occupied Zn 3d orbitals with those of the bridging O 2p states, strongly depending on the position of the orbitals.

Trends in C-O and N-O bond scission on rutile oxides described using oxygen vacancy formation energies.

Reactivity trends on transition metals can generally be understood through the d-band model, but no analogous theory exists for transition metal oxides. This limits the generality of analyses in oxide-based catalysis and surface chemistry and has motivated the appearance of numerous descriptors. Here we show that oxygen vacancy formation energy (Δ ) is an inexpensive yet accurate and general descriptor for trends in transition-state energies, which are usually difficult to assess.

Boosting the catalysis of gold by O activation at Au-SiO interface.

Supported gold (Au) nanocatalysts have attracted extensive interests in the past decades because of their unique catalytic properties for a number of key chemical reactions, especially in (selective) oxidations. The activation of O on Au nanocatalysts is crucial and remains a challenge because only small Au nanoparticles (NPs) can effectively activate O. This severely limits their practical application because Au NPs inevitably sinter into larger ones during reaction due to their low Taman temperature.

Structure of the Au Ag (S-Adm) Nanocluster and Its Application for Photocatalytic Degradation of Organic Pollutants.

Ligands play an important role in determining the atomic arrangement within the metal nanoclusters. Here, we report a new nanocluster [Au Ag (S-Adm) ] protected by bulky adamantanethiol ligands which was obtained through a one-pot synthesis. The total structure of [Au Ag (S-Adm) ] comprises an Au Ag icosahedral core, three Au (SR) units, and one AgS staple motif in contrast to the 15-atom bipyramidal core previously seen in [Au Ag (SR) ].

Self-activated surface dynamics in gold catalysts under reaction environments.

Nanoporous gold (NPG) with sponge-like structures has been studied by atomic-scale and microsecond-resolution environmental transmission electron microscopy (ETEM) combined with ab initio energy calculations. Peculiar surface dynamics were found in the reaction environment for the oxidation of CO at room temperature, involving residual silver in the NPG leaves as well as gold and oxygen atoms, especially on {110} facets. The NPG is thus classified as a novel self-activating catalyst.

Spatially Confined Assembly of Monodisperse Ruthenium Nanoclusters in a Hierarchically Ordered Carbon Electrode for Efficient Hydrogen Evolution.

The redox units of polyaniline (PAni) are used cooperatively, and in situ, to assemble ruthenium (Ru) nanoclusters in a hierarchically ordered carbon electrode. The oxidized quinonoid imine (QI) units in PAni bond Ru complex ions selectively, whereas reduced benzenoid amine (BA) units cannot. By electrochemically tuning the ratio of QI to BA, Ru complexes are spatially confined in the outer layer of hierarchical PAni frameworks.

Light-enhanced acid catalysis over a metal-organic framework.

A Brønsted acid-functionalized metal-organic framework (MOF), MIL-101-SOH, was prepared for acid-engaged esterification reactions. Strikingly, for the first time, the MOF exhibits significantly light-enhanced activity and possesses excellent activity and recyclability, with even higher activity than HSO under light irradiation.

Charge ordering and magnetic frustration in CsFeF.

The structural, electronic and magnetic properties of a charge-ordered iron fluoride material CsFeFeF have been explored by density functional theory calculations based on the generalized gradient approximation  +  U approach, which was implemented in the VASP code. The material exhibits a 3D pyrochlore-related structure which consists of corner-shared FeF and FeF octahedra. Our results confirm that CsFeF is a Mott-Hubbard insulator, and bears a magnetically frustrated ground state in which the localized 3d electrons are antiferromagnetically coupled between the homogeneous Fe ions (Fe-Fe along the b axis, and Fe-Fe along the a axis), while interactions between the heterogeneous Fe ions (Fe-Fe along the c axis) are frustrated, consistent with Goodenough-Kanamori superexchange interactions.

Establishing and Understanding Adsorption-Energy Scaling Relations with Negative Slopes.

Adsorption-energy scaling relations are widely used for the design of catalytic materials. To date, only linear scaling relations are known in which the slopes are positive. Considering the adsorption energies of F, O, N, C, and B on transition metals, we show here that scaling relations with negative slopes also exist between certain adsorbates.

Stepwise displacement of catalytically active gold nanoparticles on cerium oxide.

Aberration-corrected environmental transmission electron microscopy (ETEM) proved that catalytically active gold nanoparticles (AuNPs) move reversibly and stepwise by approximately 0.09 nm on a cerium oxide (CeO2) support surface at room temperature and in a reaction environment. The lateral displacements and rotations occur back and forth between equivalent sites, indicating that AuNPs are loosely bound to oxygen-terminated CeO2 and may migrate on the surface with low activation energy.

A thorough investigation of the active titanium species in TS-1 zeolite by in situ UV resonance raman spectroscopy.

A thorough investigation of the active titanium species in TS-1 zeolite was conducted by in situ UV resonance Raman spectroscopy combined with UV/Vis diffuse reflectance spectroscopy, DFT calculations, and epoxidation experiments. A new titanium species was identified with a characteristic Raman band at 695 cm(-1) when excited at the 266 nm laser line. It is shown that the newly found titanium species is active in the epoxidation reactions in addition to the tetrahedrally coordinated titanium species.

Theoretical study of atomic oxygen on gold surface by Hückel theory and DFT calculations.

It is fundamental to understand the behavior of atomic oxygen on gold surfaces so as to elucidate the mechanism of nano gold catalysts for low-temperature CO oxidation reactions since the atomic oxygen on gold system is an important intermediate involved in both the processes of O(2) dissociation and CO oxidation. We performed theoretical analysis of atomic oxygen adsorption on gold by using Hückel theory. It is found that formation of linear O-Au-O structure on Au surfaces greatly stabilizes the atomic oxygen adsorption due to stronger bond energy and bond order, which is confirmed subsequently by density functional theory (DFT) calculations.

Visualizing gas molecules interacting with supported nanoparticulate catalysts at reaction conditions.

Understanding how molecules can restructure the surfaces of heterogeneous catalysts under reaction conditions requires methods that can visualize atoms in real space and time. We applied a newly developed aberration-corrected environmental transmission electron microscopy to show that adsorbed carbon monoxide (CO) molecules caused the {100} facets of a gold nanoparticle to reconstruct during CO oxidation at room temperature. The CO molecules adsorbed at the on-top sites of gold atoms in the reconstructed surface, and the energetic favorability of this reconstructed structure was confirmed by ab initio calculations and image simulations.