### Recent Submissions

• #### Propane Dehydrogenation Catalyzed by Single Lewis Acid Site in Sn-Beta Zeolite

(Journal of Catalysis, Elsevier BV, 2021-01) [Article]
The gap between supply and demand of propylene has become more and more evident, because of a large consumption of the downstream products derived from propylene. Propane dehydrogenation (PDH) constitutes an important alternative for the production of propylene, and thus considerable attention has been paid to the development of eco-friendly and cost-efficient catalysts for this process. Herein, we discover that the Sn-Beta zeolite with Lewis acid sites can activate the C-H bond, and exhibits high catalytic performance in the PDH. XRD, STEM, and XPS characterizations confirm that Sn species are incorporated into the zeolite framework, and H2-TPR suggests that there is a strong interaction between Sn species and zeolite framework. It is found that the Lewis acid is the active site for dehydrogenation reaction, and the Brønsted acid is responsible for cracking reaction. The dehydrogenation rate/cracking rate is positively proportional to the L/B ratio, and a high L/B ratio is beneficial for the propane dehydrogenation reaction. The Na-Sn-Beta-30 catalyst possessing the highest amount of Lewis acid but the lowest Brønsted/Lewis ratio, exhibits the best performance in the PDH, which delivers propane conversion of 40% and propylene selectivity of 92%. Most importantly, these Sn-Beta zeolites are extremely stable without any detectable deactivation under the harsh reaction condition for 72 hours. Density functional theory calculations reveal that both Sn and adjacent O atom or OH group cooperatively act as the active sites. The PDH occurs through the direct reaction mechanism in which hydrogen molecule is produced by the direct coupling of H atom of primary C3H7 motif with the Brønsted proton in closed sites or the proton of water in open sites. It seems that open sites are more reactive than the closed ones, and the intrinsic enthalpy barriers are calculated to be 242 ∼ 301 kJ/mol depending on the hydroxylation extents. These efficient Sn-Beta zeolites could provide a new possibility for the development of a new generation of PDH catalysts with a high stability for the production of propylene.
• #### Noble metal nanowire arrays as an ethanol oxidation electrocatalyst

(Nanoscale Advances, Royal Society of Chemistry (RSC), 2021) [Article]
Vertically aligned noble metal nanowire arrays were grown on conductive electrodes based on a solution growth method. They show significant improvement of electrocatalytic activity in ethanol oxidation, from a re-deposited sample of the same detached nanowires. The unusual morphology provides open diffusion channels and direct charge transport pathways, in addition to the high electrochemically active surface from the ultrathin nanowires. Our best nanowire arrays exhibited much enhanced electrocatalytic activity, achieving a 38.0 fold increase in specific activity over that of commercial catalysts for ethanol electrooxidation. The structural design provides a new direction to enhance the electrocatalytic activity and reduce the size of electrodes for miniaturization of portable electrochemical devices.
• #### Light Propagation and Radiative Exciton Transport in Two-Dimensional Layered Perovskite Microwires

(ACS Photonics, American Chemical Society (ACS), 2020-12-29) [Article]
Layered quasi-two-dimensional perovskites are promising candidates for optoelectronic applications exhibiting excitons with high emission quantum yields, high stability, and ease of bandgap tunability. Here, we demonstrate a long-range (∼100 μm) exciton transfer in a layered perovskite structure (en)4Pb2Br9·3Br, with the ethylene diammonium (en) as a spacer that takes place via the reabsorption of emitted photons. Using the two-objectives setup, we directly map the spatiotemporal dynamics of photoluminescence (PL) from perovskite microwires that reveal a clear spectroscopic signature of photon recycling: the appearance of PL emission rise times and the corresponding elongation of the PL decay as a function of separation distance between the excitation and emission locations. We further show that a kinetic model based on the photon-mediated mechanism of the lateral exciton propagation indeed successfully describes all the salient features of the experimental data and gives an independent assessment of the radiative efficiency of the exciton recombination. Our demonstration points out the possibility of judiciously exploiting light management strategies for future high-performance optoelectronic devices with layered perovskite structures.
• #### Well-defined poly(ester amide)-based homo- and block copolymers by one-pot organocatalytic anionic ring-opening copolymerization of N-sulfonyl aziridines and cyclic anhydrides

(Angewandte Chemie International Edition, Wiley, 2020-12-22) [Article]
We report a new synthetic methodology for poly(ester amide)s by anionic ring-opening copolymerization of N -sulfonyl aziridines and cyclic anhydrides. Phosphazenes organocatalysts have been found to promote a highly-active, controlled, and selective, alternating copolymerization in the absence of any competitive side reaction (zwitterionic and transacylation). Mechanistic studies have shown first-order dependence of the copolymerization rate on N -sulfonyl aziridines and phosphazenes, and zero-order on cyclic anhydrides. This one-pot methodology leads not only to homopolymers but also to poly(ester amide)-based block copolymers. Two catalytic cycles involving ring-opening alternating copolymerization of N -sulfonyl aziridines with cyclic anhydrides and ring-opening polymerization of N -sulfonyl aziridines have been proposed to explain the one-pot synthesis of poly(ester amide)-based homo- and block copolymers.
• #### Fundamentals and applications of photo-thermal catalysis

(Chemical Society Reviews, Royal Society of Chemistry (RSC), 2020-12-18) [Article]
Photo-thermal catalysis has recently emerged as an alternative route to drive chemical reactions using light as an energy source. Through the synergistic combination of photo- and thermo-chemical contributions of sunlight, photo-thermal catalysis has the potential to enhance reaction rates and to change selectivity patterns, even under moderate operation conditions. This review provides the fundamentals of localized surface plasmon resonance (LSPR) that explain the photo-thermal effect in plasmonic structures, describes the different mechanistic pathways underlying photo-thermal catalysis, suggests methodologies to disentangle the reaction mechanisms and proposes material design strategies to improve photo-thermal performance. Ultimately, the goal is to pave the way for the wide implementation of this promising technology in the production of synthetic fuels and chemicals
• #### [Cu23(PhSe)16(Ph3P)8(H)6]·BF4: Atomic-Level Insights into Cuboidal Polyhydrido Copper Nanoclusters and Their Quasi-simple Cubic Self-Assembly

(ACS Materials Letters, American Chemical Society (ACS), 2020-12-17) [Article]
Polyhydrido copper nanoclusters are an emerging class of nanomaterials. Unfortunately, insights into the structural evolution and structure–property relationship of such copper nanoclusters are scant, because of the difficulty of synthesizing and crystallizing nanoclusters with high nuclearity and new morphologies. Here, we report an anisotropic cuboidal polyhydrido copper nanocluster, [Cu23(PhSe)16(Ph3P)8(H)6]·BF4, with a distorted cuboctahedral Cu13 core stabilized by two square protecting motifs and six hydrides. The cuboidal nanoclusters self-assemble into a quasi-simple cubic packing pattern with perfect face-to-face contact of neighboring nanoclusters and interdigitation of intercluster surface ligands. Atomic-level observations reveal the crucial role that subtle synergies between nanocluster geometry and intercluster noncovalent interactions play in guiding nanocluster self-assembly. In addition, a comparison with previously reported analogous metal nanoclusters points to bulky monodentate phosphine ligands as a potent inducing agent for the formation of rectangular hexahedral nanoclusters. These findings have significant implications for the controllable synthesis of polyhedral nanomaterials and their superstructures.
• #### Intrinsically Porous Molecular Materials (IPMs) for Natural Gas and Benzene Derivatives Separations

(Accounts of Chemical Research, American Chemical Society (ACS), 2020-12-17) [Article]
Separating and purifying chemicals without heat would go a long way toward reducing the overall energy consumption and the harmful environmental footprint of the process. Molecular separation processes are critical for the production of raw materials, commodity chemicals, and specialty fuels. Over 50% of the energy used in the production of these materials is spent on separation and purification processes, which primarily includes vacuum and cryogenic distillations. Chemical manufacturers are now investigating modest thermal approaches, such as membranes and adsorbent materials, as they are more cognizant than ever of the need to save energy and prevent pollution. Porous materials, such as zeolites, metal–organic frameworks (MOFs), and covalent organic frameworks (COFs), have dominated the field of industrial separations as their high surface areas and robust pores make them ideal candidates for molecular separations of gases and hydrocarbons. Separation processes involving porous materials can save 70%–90% of energy costs compared to that of thermally driven distillations. However, most porous materials have low thermal, chemical, and moisture stability, in addition to limited solution processability, which tremendously constrain their broad industrial translation. Intrinsically porous molecular materials (IPMs) are a subclass of porous molecular materials that are comprised of molecular host macrocycles or cages that absorb guests in or around their intrinsic cavity. IPMs range from discrete porous molecules to assemblies with amorphous or highly crystalline structures that are held together by weak supramolecular interactions. Compared to the coordination or dynamic covalent bond-constructed porous frameworks, IPMs possess high thermal, chemical, and moisture stability and maintain their porosity under critical conditions. Moreover, the intrinsic porosity endows IPMs with excellent host–guest properties in solid, liquid (organic or aqueous), and gas states, which can be further utilized to construct diverse separation strategies, such as solid–gas adsorption, solid–liquid absorption, and liquid–liquid extraction. The diversity of host–guest interactions in the engineered IPMs affords a plethora of possibilities for the development of the ideal “molecular sieves”. Herein, we present a different take on the applicability of intrinsically porous materials such as cyclodextrin (CD), cucurbiturils (CB), pillararene (P), trianglamines (T), and porous organic cages (POCs) that showed an impressive performance in gas purification and benzene derivatives separation. IPMs can be easily scaled up and are quite stable and solution processable that consequently facilitates a favorable technological transformation from the traditional energy-intensive separations. We will account for the main advances in molecular host–guest chemistry to design “on-demand” separation processes and also outline future challenges and opportunities for this promising technology.
• #### Calcium Looping: On the Positive Influence of SO2 and the Negative Influence of H2O on CO2 Capture by Metamorphosed Limestone-Derived Sorbents

(ACS Omega, American Chemical Society (ACS), 2020-12-07) [Article]
The CO2 capture performance of sorbents derived from three distinct limestones, including a metamorphosed limestone, is studied under conditions relevant for calcium looping CO2 capture from power plant flue gas. The combined and individual influence of flue gas H2O and SO2 content, the influence of textural changes caused by sequential calcination/carbonation cycles, and the impact of CaSO4 accumulation on the sorbents’ capture performance were examined using bubbling fluidized bed reactor systems. The metamorphosed limestone-derived sorbents exhibit atypical capture behavior: flue gas H2O negatively influences CO2 capture performance, while limited sulfation can positively influence CO2 capture, with space time significantly impacting CO2 and SO2 co-capture performance. The morphological characteristics influencing sorbents’ capture behavior were examined using imaging and material characterization tools, and a detailed discussion is presented. This insight into the morphology responsible for metamorphosed limestone-derived sorbent’s anomalous capture behavior can guide future sorbent selection and design efforts.
• #### Unraveling the New Role of an Ethylene Carbonate Solvation Shell in Rechargeable Metal Ion Batteries

(ACS Energy Letters, American Chemical Society (ACS), 2020-12-07) [Article]
Electrolytes play a critical role in controlling metal-ion battery performance. However, the molecular behavior of electrolyte components and their effects on electrodes are not fully understood. Herein, we present a new insight on the role of the most commonly used ethylene carbonate (EC) cosolvent both with the bulk and at the electrolyte-electrode interface. We have discovered a new phenomenon that contributes to stabilizing the electrolyte, besides the well-known roles of dissociating metal salt and forming a solid electrolyte interphase (SEI). As a paradigm, we confirm that EC can form an Li+–EC pair in a priority compared to other kinds of solvents (e.g., ethyl methyl carbonate) and then alter the Li+–solvent interactions in the electrolyte. The Li+–EC pair can dominate the desolvation structure at the electrode interface, therefore suppressing Li+–solvent decomposition due to the higher stability of Li+–EC. Our viewpoint is confirmed in different electrolytes for lithium, sodium, and potassium ion batteries, where the SEI is shown to be limited for stabilizing the electrode in the case of the less stable Li+–solvent pair. Our discovery provides a general explanation for the effect of EC and provides new guidelines for designing more reliable electrolytes for metal (ion) batteries.
• #### Efficient Visible-Light Driven Photothermal Conversion of CO 2 to Methane by Nickel Nanoparticles Supported on Barium Titanate

(Advanced Functional Materials, Wiley, 2020-12-04) [Article]
Solar-driven methanation represents a potentially cost-efficient and environmentally friendly route for the direct hydrogenation of CO2. Recently, photothermal catalysis, which involves the combination of both photochemical and thermochemical pathways, has emerged as a promising strategy for the production of solar fuels. For a photothermal catalyst to efficiently convert CO2 under illumination, in the absence of external heating, effective light harvesting, an excellent photothermal conversion and efficient active sites are required. Here, a new composite catalyst consisting of Ni nanoparticles supported on barium titanate that, under optimal reaction conditions, is able to hydrogenate CO2 to CH4 at nearly 100% selectivity with production rates as high as 103.7 mmol g–1 h–1 under both UV–visible and visible irradiation (production rate: 40.3 mmol g−1 h–1) is reported. Mechanistic studies suggest that reaction mostly proceeds through a nonthermal hot-electron-driven pathway, with a smaller thermal contribution.
• #### High trans-Selectivity in Boron-Catalyzed Polymerization of Allylic Arsonium Ylide and its Contribution to Thermal Properties of C3-Polymers

(Macromolecules, American Chemical Society (ACS), 2020-12-01) [Article]
Boron-catalyzed polymerization offers unique C3-polymer structures because, in contrast to 1,4-polydienes, each double bond is separated by only one methylene group. However, the geometrical regularity of such unique C3-structures was less discussed, and their properties have not been reported. In this work, well-defined poly(2-methyl-propenylene)s with different molecular weights are prepared in the gram scale by boron-catalyzed polymerization of 2-methylallyl arsonium ylide. 1H NMR, 13H NMR, and two-dimensional 1H–13C heteronuclear single quantum coherence NMR spectra confirm the high selectivity toward trans-configuration (>99%) and C3 monomeric insertion (>98%). Density functional theory (DFT) calculations at the wb97xd/tzvp level (solvent = tetrahydrofuran) explain the high trans/C3. Furthermore, the thermal parameters, Tc, Tm, Tg, ΔHc, ΔHm, and crystallinity degree, of poly(2-methyl-propenylene)s are determined by differential scanning calorimetry (DSC), fast scanning chip calorimetry (Flash DSC), and Wide Angle X-ray Scattering (WAXS) for the first time and are compared with those of trans-polyisoprene.
• #### Differential guest location by host dynamics enhances propylene/propane separation in a metal-organic framework

(Nature Communications, Springer Science and Business Media LLC, 2020-11-30) [Article]
AbstractEnergy-efficient approaches to propylene/propane separation such as molecular sieving are of considerable importance for the petrochemical industry. The metal organic framework NbOFFIVE-1-Ni adsorbs propylene but not propane at room temperature and atmospheric pressure, whereas the isostructural SIFSIX-3-Ni does not exclude propane under the same conditions. The static dimensions of the pore openings of both materials are too small to admit either guest, signalling the importance of host dynamics for guest entrance to and transport through the channels. We use ab initio calculations together with crystallographic and adsorption data to show that the dynamics of the two framework-forming units, polyatomic anions and pyrazines, govern both diffusion and separation. The guest diffusion occurs by opening of the flexible window formed by four pyrazines. In NbOFFIVE-1-Ni, (NbOF5)$^{2−}$ anion reorientation locates propane away from the window, which enhances propylene/propane separation.
• #### Recent Advances in Nickel-Catalyzed C-Heteroatom Cross-Coupling Reactions under Mild Conditions via Facilitated Reductive Elimination.

(Angewandte Chemie (International ed. in English), Wiley, 2020-11-30) [Article]
The formation of C-heteroatom bonds represents an important type of bond-forming reaction in organic synthesis and often provides a fast and efficient access to privileged structures found in pharmaceuticals, agrochemical and materials. In contrast to conventional Pd- or Cu-catalyzed C-heteroatom cross-couplings under high-temperature conditions, recent advances in homo- and heterogeneous Ni-catalyzed C-heteroatom formations under mild conditions are particularly attractive from the standpoint of sustainability and practicability. The generation of Ni III and excited Ni II intermediates facilitate the reductive elimination step to achieve mild cross-couplings. This minireview provides an overview of the state-of-the-art approaches for mild C-heteroatom bond formations highlights the developments in photoredox and nickel dual catalysis involving SET and energy transfer processes; photoexcited nickel cataylsis; electro and nickel dual catalysis; heterogeneous photoredox and nickel dual catalysis involving graphitic carbon nitride (mpg-CN), metal organic frameworks (MOFs) or semiconductor quantum dots (QDs); as well as more conventional zinc and nickel dual catalyzed reactions.
• #### Mixed-dimensional MXene-hydrogel heterostructures for electronic skin sensors with ultrabroad working range

(Science Advances, American Association for the Advancement of Science (AAAS), 2020-11-27) [Article]
Skin-mountable microelectronics are garnering substantial interest for various promising applications including human-machine interfaces, biointegrated devices, and personalized medicine. However, it remains a critical challenge to develop e-skins to mimic the human somatosensory system in full working range. Here, we present a multifunctional e-skin system with a heterostructured configuration that couples vinyl-hybrid-silica nanoparticle (VSNP)–modified polyacrylamide (PAM) hydrogel with two-dimensional (2D) MXene through nano-bridging layers of polypyrrole nanowires (PpyNWs) at the interfaces, featuring high toughness and low hysteresis, in tandem with controlled crack generation and distribution. The multidimensional configurations endow the e-skin with an extraordinary working range (2800%), ultrafast responsiveness (90 ms) and resilience (240 ms), good linearity (800%), tunable sensing mechanisms, and excellent reproducibility. In parallel, this e-skin platform is capable of detecting, quantifying, and remotely monitoring stretching motions in multiple dimensions, tactile pressure, proximity sensing, and variations in temperature and light, establishing a promising platform for next-generation smart flexible electronics.
• #### CCDC 1406311: Experimental Crystal Structure Determination

(Cambridge Crystallographic Data Centre, 2020-11-27) [Dataset]
• #### CCDC 1044413: Experimental Crystal Structure Determination :

(Cambridge Crystallographic Data Centre, 2020-11-27) [Dataset]
• #### CCDC 1941207: Experimental Crystal Structure Determination

(Cambridge Crystallographic Data Centre, 2020-11-26) [Dataset]
• #### CCDC 1941208: Experimental Crystal Structure Determination

(Cambridge Crystallographic Data Centre, 2020-11-26) [Dataset]
• #### Cobalt carbide nanosheets as effective catalysts toward photothermal degradation of mustard-gas simulants under solar light

(Applied Catalysis B: Environmental, Elsevier BV, 2020-11-26) [Article]
Here, ultrathin cobalt carbide (Co2C) nanosheets are firstly illustrated as effective and robust catalysts toward photothermal degradation of sulfur mustard simulants (e.g., 2-chloroethyl ethyl sulfide, CEES) under solar light. Under the optimal conditions, the degradation rate of CEES by Co2C nanosheets is up to 98 %, which is much higher than the widely used P25 and anatase TiO2 nanoparticles. Moreover, the degradation performance is comparable or even better than those typical photothermal catalysts, including MnO2, MnOx-TiO2 and Co3O4, under identical conditions. Experimental evidences and density functional theory (DFT) calculations reveal that the superior activity is attributed to three main reasons: (i) the high photo-to-heat conversion efficiency of Co2C enables an elevated surface temperature for chemical bond breaking, (ii) the feasible binding of CEES on Co2C surface via Co–S and Co–Cl coordination promotes the process of degradation, and (iii) the surface hydroxyl groups (–OH) on Co2C nanosheets favor the degradation of CEES. Obviously, this work provides new insights into practical and large-scale application of transition metal carbides (TMCs) as novel photothermal catalysts in the decontamination of chemical warfare agents (CWAs) under ambient conditions (i.e., solar light and room temperature).
• #### Axially chiral bis-1,2,3-Triazol-4-ylidene–Ag(I)-MIC and, bis-Au(I)-MIC complexes of (R)-BINOL and (-)-Menthol scaffold: Synthesis, structure, and characterizations

(Journal of Organometallic Chemistry, Elsevier BV, 2020-11-26) [Article]
Herein, we report the novel axially chiral bis-Ag(I)-MIC and, bis-Au(I)-MIC complexes bearing axially chiral bis-1,2,3-triazolium-derived mesoionic carbene (tz-MIC) ligands were synthesized. The enantiopure R-BINOL was employed as a basic unit to synthesize a axially chiral bis-1,2,3-triazolium-derived mesoionic carbene (tz-MIC) ligands (1–2)a. In particular, the axially chiral bis-1,2,3-triazolium-derived mesoionic carbene (tz-MIC) ligands (1–2)a, were obtained from the reaction of corresponding bis-1,2,3-triazole ligand precursor with methyl and ethyl iodide in 82−90% yields. Novel axially chiral bis-Ag(I)-MIC complexes (1 − 2)b, were prepared by the treatment of corresponding axially chiral bis-1,2,3-triazolium-derived mesoionic carbene (tz-MIC) iodide salts, (1 − 2)a, with Ag2O via in-situ deprotonation method in 69−86% yields. Novel axially chiral bis-Au(I)-MIC complex-2c was synthesized from their respective novel axially chiral bis-Ag(I)-MIC complex-2b, using transmetallation reaction with (SMe2)AuCl in 70% yield. All these novel axially chiral bis-Ag(I)-MIC and bis-Au(I)-MIC complexes were isolated for the first time and structurally characterized by 1H NMR and 13C{1H}-NMR spectroscopy, FT-IR spectroscopy, mass spectrometry, elemental analysis, specific optical rotation and, single crystal X-ray crystallography.