A novel strategy for the controlled synthesis of 2D MoS2/C hybrid nanosheets consisting of the alternative layer-by-layer interoverlapped single-layer MoS2 and mesoporous carbon (m-C) is demonstrated. Such special hybrid nanosheets with a maximized MoS2 /m-C interface contact show very good performance for lithium-ion batteries in terms of high reversible capacity, excellent rate capability, and outstanding cycling stability.

Most Li+/Na+-conducting solid electrolytes are unstable in moisture, and the formed hydroxides and carbonates on their surfaces result in the increase of the interfacial resistance between solid electrolytes and alkali metal anodes. In this study, heat treatment was used to remove the byproduct coating on the surface of Na3Zr2Si2PO12 (NZSP) that also leads to the generation of Na-ion deficient surface simultaneously. This surface chemistry approach was used to reduce the interfacial resistance and suppress Na-dendrite growth during Na plating. A combination of the metallic Na wetting test, density functional theory, and electrochemical measurement was employed to investigate the origins of ultralow interfacial resistance and mechanism between the Na-ion deficient surface and the metallic Na anode. The analysis demonstrates that the Na-ion-deficient surface effectively improves the contact between NZSP and the metallic Na anode. Moreover, an ultrathin passivating layer involving Na2O was formed between NZSP with metallic Na that protected the NZSP electrolyte from the reduction by metallic Na. This study not only motivates the need for further understanding of the surface chemistry of NZSP but also provides guidelines for the future design of the Na-ion solid–electrolyte interface.

The existence of a defective area composed of nanocrystals and amorphous phases on a perovskite film inevitably causes nonradiative charge recombination and structural degradation in perovskite photovoltaics. In this study, a stoichiometric etching strategy for the top surface of a defective cesium lead halide perovskite is developed by using ionic liquids. The dissolution of the original defective area substantially exposes the underlying perovskite, which is a high‐quality surface with retained stoichiometry and lattice continuity. The ionic liquid molecules are adsorbed on the perovskite surface via Coulombic interactions and passivate the undercoordinated surface lead centers. Such a structural modulation considerably reduces the trap density of the perovskite devices and enables a record power conversion efficiency of 17.51% and an open‐circuit voltage of 1.37 V of the CsPbI2Br cell with a perovskite bandgap of 1.88 eV. This work provides a novel technical route to improve the efficiency and environmental resilience of perovskite‐based optoelectronic devices.

To understand the molecular-level reaction mechanism and crucial activity-limiting factors of the NH3-SCR process catalyzed by MnO2-based oxide to eliminate NO (4NH3 + 4NO + O2 →4N2 + 6H2O) at middle–low temperature, a systematic computational investigation is performed on β-MnO2(110) by first-principles calculations together with microkinetic analysis. Herein, the favored reaction pathways are unveiled. (i) NH3 tends to adsorb at the unsaturated Lewis acid Mn5c site on MnO2(110) and then partially dissociates into NH2* (assisted by the surface lattice Obri) at the steady state, triggering the subsequent reactions. (ii) Interestingly, NO, either in the gas phase or at the adsorbed state, can readily react with NH2* to give the key intermediate NH2NO, with the former (i.e., the Eley–Rideal pathway) being slightly more kinetically preferred. (iii) NH2NO conversion is identified to proceed easily to N2 through the dehydrogenation/hydrogenation processes NH2NO → NHNO → NHNOH → N2 + H2O. (iv) The removal of the accumulated surface H into H2O, assisted by O2, is relatively difficult, which preferentially occurs via the Mars–van Krevelen mechanism. Quantitatively, a kinetic analysis is conducted to deal with such a complex reaction network, revealing that the rate-limiting steps are NH2* + NO­(g) → NH2NO* and ObriH + O2# →OOH# + Obri. Moreover, a sensitivity analysis shows that the adsorption strengths of H on Obri and O2 in the Obri vacancy (Ovac) are two main activity-determining factors for the overall NH3-SCR on MnO2(110); notably, it is further found that the Ovac formation energy correlates well with both factors and can thus serve as a unified activity descriptor. In addition, the effects of catalyst surface environment under the reaction conditions on the NH3-SCR activity and selectivity are discussed. In comparison with the pristine state of MnO2(110), both the overall activity and N2 selectivity (versus N2O) would be interestingly enhanced when it arrives at the kinetically steady state that the surface Obri are largely covered by H. These results could provide a consolidated theoretical basis for understanding and optimizing MnO2 catalysts for the NH3-SCR process.

The organic carboxylic acid coordinated monomeric peroxoniobate-based ionic liquids (ILs) [TBA]­[NbO­(OH)2(R)] (TBA = tetrabutylammonium; R = lactic acid (LA), glycolic acid (GLY), malic acid (MA)) were prepared and fully characterized by elemental analysis, NMR, IR, Raman, TGA, 93Nb NMR, and HRMS. These IL catalysts exhibited not only high catalytic activity for the epoxidation of olefins under very mild reaction conditions, as the turnover frequency of [TBA]­[NbO­(OH)2(LA)] reached up to 110 h–1, but also satisfactory recyclability in the epoxidation by using only 1 equiv of hydrogen peroxide as an oxidant. Meanwhile, this work revealed that the ILs underwent structural transformation from [NbO­(OH)2(R)]− to [Nb­(O–O)2(R)]− (R = LA, GLY, MA) in the presence of H2O2 by a subsequent activity evaluation, characterization, and first-principles calculations. Moreover, the organic carboxylic acid coordinated monomeric peroxoniobate-based ILs were investigated using density functional theory (DFT) calculations, which identified that [Nb­(O–O)2LA]− was more advantageous than [Nb­(O–O)2(OOH)2]− for the epoxidation of olefins. Due to the coordination between the α-hydroxy acids and the monomeric peroxoniobate anions, the functionalized ILs can efficiently catalyze the epoxidation of a wide range of olefins and allylic alcohols under very mild conditions. Additionally, the effect of solvents on the reaction is illustrated. It was found that methanol can lower the epoxidation barriers by forming a hydrogen bond with a peroxo ligand attached to the niobium center.

This work reports new kinds of monomeric peroxoniobate anion functionalized ionic liquids (ILs) designated as [A+]­[NbO­(O-O)­(OH)2] (A+ = tetrapropylammonium, tetrabutylammonium, or tetrahexylammonium cation), which have been prepared and characterized by elemental analysis, HRMS, NMR, IR, TGA, etc. With hydrogen peroxide as an oxidant, these ILs exhibited excellent catalytic activity and recyclability in the epoxidation of various allylic alcohols under solvent-free and ice bath conditions. Interestingly, subsequent activity tests and catalyst characterization together with first-principles calculations indicated that the parent [NbO­(O-O)­(OH)2]− anion has been oxidized into the anion [Nb­(O-O)2(OOH)2]− in the presence of H2O2, which constitutes the real catalytically active species during the reaction; this anion has higher activity in comparison to the analogous peroxotungstate anion. Moreover, the epoxidation process of the substrate (allylic alcohol) catalyzed by [Nb­(O-O)2(OOH)2]− was explored at the atomic level by virtue of DFT (density functional theory) calculations, identifying that it is more favorable to occur through a hydrogen bond mechanism, in which the peroxo group of [Nb­(O-O)2(OOH)2]− serves as the adsorption site to anchor the substrate OH group by forming a hydrogen bond, while OOH as the active oxygen species attacks the CC bond in substrates to produce the corresponding epoxide. This is the first example of the highly efficient epoxidation of allylic alcohols using a peroxoniobate anion as a catalyst.

Effective adsorption and speedy surface reactions are vital requirements for efficient active sites in catalysis, but it remains challenging to maximize these two functions simultaneously. We present a solution to this issue by designing a series of atom-pair catalytic sites with tunable electronic interactions. As a case study, NO selective reduction occurring on V 1 À W 1 /TiO 2 is chosen. Experimental and theoretical results reveal that the synergistic electron effect present between the paired atoms enriches high-energy spin charge around the Fermi level, simultaneously rendering reactant (NH 3 or O 2 ) adsorption more effective and subsequent surface reactions speedier as compared with single V or W atom alone, and hence higher reaction rates. This strategy enables us to rationally design a high-performance V 1 À Mo 1 /TiO 2 catalyst with optimized vanadium(IV)molybdenum(V) electronic interactions, which has exceptional activity significantly higher than the commercial or reported catalysts.

To meet the requirements for sustainable development, photocatalytic applications including water splitting, CO2 reduction, pollutant degradation, and organic conversion reactions have become hot topics for research, due to the predictable advantages of energy storage and transportation. Metal–organic frameworks (MOFs) featured with porosity, crystallinity, and tunable constitution offer enormous potential in photocatalytic applications. Herein, a critical overview of MOFs‐based photocatalysts is presented. Following a concise introduction of the structural characteristics of MOFs, the synthesis methods of MOFs‐based photocatalysts are summarized. Moreover, subtle modification strategies for MOFs inspired by the development of other inorganic photocatalysts are also discussed on the basis of the photocatalytic mechanisms of light absorption, electron transfer, and surface catalytic reactions. Furthermore, the applications of certain MOFs‐based photocatalysts are introduced in detail. In addition, other organic frameworks‐based photocatalytic materials, such as covalent organic frameworks and covalent triazine frameworks, are also described to provide a guided insight into the rational design and fabrication of efficient frameworks‐based photocatalysts. Finally, a brief conclusion and perspective on the opportunities and challenges for the future development of MOFs‐based photocatalysts are proposed.