Borocarbonitride Catalyzed Ethylbenzene Oxidative Dehydrogenation: Activity Enhancement via Encapsulation of Mn Clusters inside the Tube.

Borocarbonitride (BCN) catalysts, boasting multiple redox sites, have shown considerable potential in alkane oxidative dehydrogenation (ODH) to olefin molecules. However, their catalytic efficiency still lags behind that of leading commercial catalysts, primarily due to the limited reactivity of oxygen functional groups. In this study, a groundbreaking hybrid catalyst is developed, featuring BCN nanotubes (BCNNTs) encapsulated with manganese (Mn) clusters, crafted through a meticulous supramolecular self-assembly and postcalcination strategy. This novel catalyst demonstrates a remarkable enhancement in activity, achieving 30% conversion and ≈100% selectivity toward styrene in ethylbenzene ODH reactions. Notably, its performance surpasses both pure BCNNTs and those hosting Mn nanoparticles. Structural and kinetic analyses unveil a robust interaction between BCNNTs and the Mn component, substantially boosting the catalytic activity of BCNNTs. Furthermore, density functional theory (DFT) calculations elucidate that BCNNTs encapsulated with Mn clusters not only stabilize key intermediates (─B─O─O─B─) but also enhance the nucleophilicity of active sites through electron transfer from the Mn cluster to the BCNNTs. This electron transfer mechanism effectively lowers the energy barrier for ─C─H cleavage, resulting in a 13% improvement in catalytic activity compared to pure BCNNTs.

Bi2S3 nanorods grown on multiwalled carbon nanotubes as highly active catalysts for CO2 electroreduction to formate.

Bi-based materials are promising electrocatalysts for CO2 reduction but one of the key technological hurdles is the design of stable, active and affordable Bi-based catalysts over a wide potential range. Herein, Bi2S3/CNTs nanocomposites are constructed by anchoring bismuth sulfide (Bi2S3) nanorods onto the multiwalled carbon nanotubes (CNTs) and utilizing them in electrocatalytic CO2 reduction. CNTs, as a support, not only guarantee the conductivity and dispersibility of Bi2S3 nanorods but also improve the electrolyte infiltration and optimize the electronic structure of the Bi2S3. As expected, the Bi2S3/CNTs nanocomposite exhibits a faradaic efficiency for HCOO- (FEHCOO-) of 99.3% with a current density of -20.3 mA cm-2 at -0.91 V vs. RHE. The FEHCOO- is stably maintained at over > 91% in a wide potential window from -0.71 V to -1.31 V. Theoretical calculation analyses reveal that the strong interaction between Bi2S3 and CNTs is conductive to decreasing the energy barrier of *OCHO, stabilizing the intermediate *OCHO, and inhibiting the hydrogen evolution reaction. The current study provides an insightful understanding of the mechanism of the CO2 electroreduction reaction, and paves a new way for developing superior and affordable electrocatalysts.

Surface Chemistry and Catalytic Reactivity of Borocarbonitride in Oxidative Dehydrogenation of Propane.

Borocarbonitride (BCN) materials are newly developed oxidative dehydrogenation catalysts that can efficiently convert alkanes to alkenes. However, BCN materials tend to form bulky B2 O3 due to over-oxidation at the high reaction temperature, resulting in significant deactivation. Here, we report a series of super stable BCN nanosheets for the oxidative dehydrogenation of propane (ODHP) reaction. The catalytic performance of the BCN nanosheets can be easily regulated by changing the guanine dosage. The control experiment and structural characterization indicate that the introduction of a suitable amount of carbon could prevent the formation of excessive B2 O3 from BCN materials and maintain the 2D skeleton at a high temperature of 520 °C. The best-performing catalyst BCN exhibits 81.9 % selectivity towards olefins with a stable propane conversion of 35.8 %, and the propene productivity reaches 16.2 mmol h-1 g-1 , which is much better than hexagonal BN (h-BN) catalysts. Density functional theory calculation results show that the presence of dispersed rather than aggregated carbon atoms can significantly affect the electronic microenvironment of h-BN, thereby boosting the catalytic activity of BCN.

Hollow NiCoP Nanoprisms Derived from Prussian Blue Analogues as Bifunctional Electrocatalysts for Urea-Assisted Hydrogen Production in Alkaline Media.

Integrating the hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) is an energy-saving approach for electrolytic H2 production. Here, hollow NiCoP nanoprisms are derived from Prussian blue analogues by a combined self-template coordination reaction and gas-phase phosphorization strategy. Benefiting from the strong electron interaction, unique hollow nanostructure, and enhanced mass/charge transfer, NiCoP nanoprisms display outstanding alkaline HER and UOR performance. Specifically, low potentials of -0.052, -0.115, and -0.159 V for HER and ultralow potentials of 1.30, 1.36, and 1.42 V for UOR at current densities of 10, 50, and 100 mA cm-2 are obtained. Moreover, in a urea-assisted water electrolysis system, NiCoP nanoprisms only require cell voltages of 1.36, 1.49, and 1.57 V to offer current densities of 10, 50, and 100 mA cm-2 , about 170, 180, and 200 mV less than the traditional water electrolysis. Theoretical calculations indicate the Co substitution in Ni2 P promotes the adsorption and dissociation of water molecules, optimizes the desorption energy of active hydrogen atoms, and enhances the adsorption of urea molecules, thus accelerating the kinetics of HER and UOR. This work facilitates the application of hollow bimetallic phosphides in electrochemical preparation of clean energy and provides a successful paradigm for urea-rich wastewater electrolysis.

Carbon-based frustrated Lewis pairs mediate hydrogenation.

Hydrogen activation and the consequent catalytic hydrogenation of nitrobenzene on metal-free catalysts have been an attractive alternative to traditional metal-based catalytic process. Here we design a type of B/P co-doped nanocarbon (BPC) catalyst via the engineering of frustrated Lewis pairs (FLPs) on nanocarbons. It exhibits excellent catalytic activity with 97% conversion and 98% selectivity in hydrogen assisted hydrogenation of nitrobenzene to form aniline, which is superior to that of pure carbon and single B or P doped carbon materials. Structural characterizations, kinetic measurements and density functional theory (DFT) results indicate that Lewis acid ("B" center) and Lewis base ("P" center) engineered FLP sites on the BPC are responsible for the formation of aniline, and the moderate P/B ratio is important in promoting the hydrogenation activity. Moreover, we put forward a possible reaction mechanism and point out the key factors in determining the reactivity for this reaction. The current work provides a facile strategy for developing highly efficient hydrogenation catalysts.

Single-atom cobalt-fused biomolecule-derived nitrogen-doped carbon nanosheets for selective oxidation reactions.

Non-noble metal single-atom catalysts hold great promise in selective oxidation reactions, although the progress is still unsatisfactory because of the synthesis challenge and the lack of mechanistic interpretations. Herein, we develop a biomolecule-based strategy to synthesize isolated Co single atom site catalysts by one-step pyrolysis of guanosine and Co precursors. Due to the abundant hydrogen bonding and π-π interaction of guanosine, the as-synthesized Co-N-C catalysts present a hierarchical porous two-dimensional (2D) nanostructure with an ultrahigh specific surface area, large pore volume, and high density of cobalt single atoms. Aberration-corrected electron microscopy and X-ray photoelectron spectroscopy reveal that Co species are present as isolated single sites and stabilized by nitrogen-doped carbon nanosheets. These characteristics make Co-GS-900 suitable as an efficient catalyst for selective oxidation of aromatic alkanes. For oxidation of ethylbenzene, Co-GS-900 exhibits a superior performance f with 91% conversion and 98% selectivity of acetophenone.

Highly Selective CO2 Electroreduction to CH4 by In†Situ Generated Cu2 O Single-Type Sites on a Conductive MOF: Stabilizing Key Intermediates with Hydrogen Bonding.

It is still a great challenge to achieve high selectivity of CH4 in CO2 electroreduction reactions (CO2 RR) because of the similar reduction potentials of possible products and the sluggish kinetics for CO2 activation. Stabilizing key reaction intermediates by single type of active sites supported on porous conductive material is crucial to achieve high selectivity for single product such as CH4 . Here, Cu2 O(111) quantum dots with an average size of 3.5 nm are in situ synthesized on a porous conductive copper-based metal-organic framework (CuHHTP), exhibiting high selectivity of 73 % towards CH4 with partial current density of 10.8 mA cm-2 at -1.4 V vs. RHE (reversible hydrogen electrode) in CO2 RR. Operando infrared spectroscopy and DFT calculations reveal that the key intermediates (such as *CH2 O and *OCH3 ) involved in the pathway of CH4 formation are stabilized by the single active Cu2 O(111) and hydrogen bonding, thus generating CH4 instead of CO.

Carbon-Doped BN Nanosheets for the Oxidative Dehydrogenation of Ethylbenzene.

Carbon-based catalysts have demonstrated great potential for the aerobic oxidative dehydrogenation reaction (ODH). However, its widespread application is retarded by the unavoidable deactivation owing to the appearance of coking or combustion under ODH conditions. The synthesis and characterization of porous structure of BCN nanosheets as well as their application as a novel catalyst for ODH is reported. Such BCN nanosheets consist of hybridized, randomly distributed domains of h-BN and C phases, where C, B, and N were confirmed to covalent bond in the graphene-like layers. Our studies reveal that BCN exhibits both high activity and selectivity in oxidative dehydrogenation of ethylbenzene to styrene, as well as excellent oxidation resistance. The discovery of such a simple chemical process to synthesize highly active BCN allows the possibility of carbocatalysis to be explored.

Dual-Emission Luminescence of Magnesium Coordination Polymers Based on Mixed Organic Ligands.

Presented herein are two luminescent magnesium coordination polymers (Mg-CPs), namely [Mg2 (H2O)2 (2-NDC)4 (1,10-phen)2] (1) and [Mg2 (H2O)(1,4-NDC)2 (1,10-phen)] (2), in which 2-NDCH=2-naphthalenecarboxylic acid, 1,4-NDCH2 =1,4-naphthalene dicarboxylic acid, and 1,10-phen=1,10-phenanthroline. Based on the mixed ligands, the title compounds exhibit linker-based photoluminescence (PL) properties thanks to the unique configuration of the Mg(2+) ions. The two compounds show interesting dual emission on excitation of the different luminophores of the mixed linkers. In particular, the emissions of compound 2 could be tuned from green to yellow simply by varying the excitation energies. Furthermore, 2 could be excited by using a commercial λ=450 nm blue LED chip to generate white-light emission, which allows the fabrication of a white-light-emitting diode (WLED) with 20 lm W(-1) luminous efficacy. This work may provide a new method for designing tunable PL CPs by using the low-cost and abundant magnesium ion.

Entrapping an ionic liquid with nanocarbon: the formation of a tailorable and functional surface.

An interface microenvironment between nanocarbon and ionic liquids (ILs) is presented. By an entrapping effect, a few layers of ILs can be finely deposited on the surface of nanocarbon, endowing amazingly tailorable surface properties. The entrapped IL layer, which was believed to be unable to be charred under pyrolysis conditions alone, can be further carbonized to a functional carbon layer. C, B, and N were confirmed to share the same hexagonal ring in the resultant layer, which provides more designable electronic properties.

Guanine-derived carbon nanosheet encapsulated Ni nanoparticles for efficient CO2 electroreduction.

Developing novel electrocatalysts for achieving high selectivity and faradaic efficiency in the carbon dioxide reduction reaction (CO2RR) poses a major challenge. In this study, a catalyst featuring a nitrogen-doped carbon shell-coated Ni nanoparticle structure is designed for efficient carbon dioxide (CO2) electroreduction to carbon monoxide (CO). The optimal Ni@NC-1000 catalyst exhibits remarkable CO faradaic efficiency (FECO) values exceeding 90% across a broad potential range of -0.55 to -0.9 V (vs. RHE), and attains the maximum FECO of 95.6% at -0.75 V (vs. RHE) in 0.5 M NaHCO3. This catalyst exhibits sustained carbon dioxide electroreduction activity with negligible decay after continuous electrolysis for 20 h. More encouragingly, a substantial current density of 200.3 mA cm-2 is achieved in a flow cell at -0.9 V (vs. RHE), reaching an industrial-level current density. In situ Fourier transform infrared spectroscopy and theoretical calculations demonstrate that its excellent catalytic performance is attributed to highly active pyrrolic nitrogen sites, promoting CO2 activation and significantly reducing the energy barrier for generating *COOH. To a considerable extent, this work presents an effective strategy for developing high-efficiency catalysts for electrochemical CO2 reduction across a wide potential window.

Self-assembly of guanosine into carbon-based multilayer materials.

We report the utilization of guanosine as a supramolecular precursor that unprecedentedly renders the formation of carbon-based multilayer materials with naturally high-level nitrogen doping. As a proof-of-concept, the porous carbon multilayers after anchoring 0.5 wt% Rh electrocatalysts displayed an excellent hydrogen evolution reaction activity.

Core-shell Mo2C@NC/Mo2C hollow microspheres as highly efficient electrocatalysts for the hydrogen evolution reaction.

Developing low-cost and highly efficient electrocatalysts for the hydrogen evolution reaction (HER) has stimulated extensive interest. Molybdenum carbide materials have been proposed as promising alternatives to noble platinum-based catalysts due to their earth abundance and tunable physicochemical characteristics. Here, we report Mo2C@NC/Mo2C hollow microspheres composed of a ß-Mo2C core and small ß-Mo2C particles embedded within a nitrogen-doped carbon shell and prepared using guanosine and hexaammonium molybdate as precursors via a hydrothermal self-assembly process, which results in outstanding catalytic activity and fast kinetics in hydrogen evolution in both acidic and alkaline solutions. The significant activity improvement of Mo2C@NC/Mo2C can be attributed to the large ratio of exposed active sites and abundant interfacial structures. This work provides a new template-free strategy for the design of a highly active Mo2C@NC/Mo2C hollow microsphere HER catalyst.

Folic Acid-Derived Low-dimensional carbons for efficient oxidative dehydrogenation of ethylbenzene.

The oxidative dehydrogenation (ODH) of alkane is one of the most attractive routes in alkane production because of its favourable thermodynamic characteristic. Nitrogen-doped nanocarbons have demonstrated great potential in this reaction due to its cost-effective, high catalytic activity and stability. However, the influence of nitrogen on the catalytic properties of carbon materials is poorly understood due to the complexities of surface oxygen and nitrogen functional groups. Here we derive the performance descriptor that account for the nitrogen-dependent carbocatalysis in ODH reaction. To achieve this, we designed a set of nitrogen-doped nanocarbon materials with tunable nitrogen species by hydrothermal carbonization (HTC) treatment of the biomass folic acid (FA), which are applied in ODH of ethylbenzene. Among them, FA-180-1000 catalyst can achieve high ethylbenzene conversion (up to ∼62 %) and styrene selectivity (∼87 %), outperforming other HTC carbon-based catalysts. Structural characterizations and kinetic analyses revealed that nitrogen doping strongly interferes the charge polarization of CO site via electron transfer between CO, and nitrogen (mainly pyridine nitrogen and graphitic nitrogen) thus enhancing the reactivity of CO. Furthermore, the induction period during reaction process can be shortened by applying of sulfuric acid-assisted HTC method for constructing nitrogen-doped carbon catalyst with low crystallinity. The present work provides new insights into the contribution of nitrogen doping to the ODH reaction of carbon nanocatalysts, as well as guidance for the rational design of carbon catalysts for the conversion of hydrocarbons to high-value chemicals.

Guanosine-derived atomically dispersed Cu-N3-C sites for efficient electroreduction of carbon dioxide.

Single-atom copper (Cu) embedded within carbon catalysts have demonstrated significant potential in the electrochemical reduction of carbon dioxide (CO2) into valuable chemicals and fuels. Herein, we develop a straightforward and template-free strategy for synthesizing atomically dispersed CuNC catalysts (CuG) by annealing the self-assembled guanosine. The CuG catalysts display two-dimensional morphology, tunable pore size and large surface areas that can be adjusted by changing carbonization temperature. Spherical aberration-corrected transmission electron microscopy reveals that single-atom Cu are homogeneously dispersed on the surface of carbon nanosheets. The optimum CuG-1000 catalysts achieve a high CO Faradaic efficiency (FEco) up to 99% and a high CO current density of 6.53 mA cm-2 (-0.65 V vs. RHE). Besides, the flow cell test of CuG-1000 shows a high current density up to 25.2 mA cm-2 and the FEco still exceeded 91% after more than 20 h of testing. Specifically, the existence of Cu-N3-C active sites was proved by extended X-ray absorption fine structure (EXAFS). Density functional theory evidences that tricoordinated copper with N can largely regulate the adsorption and desorption of key intermediates by transferring electrons to *COOH through Cu atoms, thereby improving selectivity toward CO. This work demonstrates the active origin of CuNC catalysts in CO2 electroreduction and offers a blueprint to construct atomically dispersed transition site catalysts by supramolecular self-assembly strategy.

Green synthesis of carbon-supported ultrafine ZnS nanoparticles for superior lithium-ion batteries.

Zinc sulfide (ZnS) is a promising anode material for lithium-ion batteries (LIBs) because of its high theoretical capacity, abundance, cost-effectiveness, and environmental friendliness. Herein, a hydrangea-like ZnS-carbon composite (ZnS-NC) is synthesized through the hydrothermal method and subsequent pyrolysis of a supramolecular precursor guanosine. The resulting composite comprises ultrafine ZnS nanoparticles firmly stabilized on a nitrogen-doped carbon matrix, featuring mesoporous channels and high surface areas. When utilized as an anode material for LIBs, the initial discharge specific capacity of the ZnS-NC electrode reaches an impressive value of 944 mA h g-1 at 1.0 A g-1, and even after 450 cycles, it maintains a reversible capacity of 597 mA h g-1. Compared with pure ZnS, the ZnS-NC composite exhibits significantly improved rate performance and cycling stability. This enhancement in Li-storage performance can be attributed to a synergistic effect within the ZnS-NC composite, which arises from the large exposed active site area, efficient ion/electron transfer, and strong interaction between the ZnS nanoparticles and the carbon framework. Overall, this work presents an eco-friendly approach for developing metal sulfide-carbon composites with exceptional potential for energy storage applications.

Role of carbon quantum dots on Nickel titanate to promote water oxidation reaction under visible light illumination.

Water oxidation reaction (WOR) is the heart for overall water splitting owing to its sluggish kinetics. Herein, carbon quantum dots (CQDs) are studied as co-catalyst to promote WOR by loading them on NiTiO3 (NTO) photocatalyst. The performance can be obtained in a fold of 7 compared with pristine NTO in power-based photocatalytic system, and strong stability has received with preserving the output for at least 10 h. The CQDs have also demonstrated to load on NTO based photoanode for WOR, and a 6 times increasement has realized. In-situ characterizations have acquired to study the roles of CQDs for WOR and found that CQDs can facilitate the chemical adsorption of water molecules, and meanwhile promote the formation of hydroxyl radical as transition states of WOR. This demonstration presents a clue to understand the role of carbon in photocatalytic system to promote WOR and encourage its uses for advanced photoredox catalytic reactions.

Identification of active sites of B/N co-doped nanocarbons in selective oxidation of benzyl alcohol.

Developing highly active and stable nanocarbon catalysts for selective oxidation reactions has attracted much attention due to their potential as an alternative to traditional metal-based or noble metal catalysts. However, the nature of active sites and the reaction mechanism of nanocarbon catalysts for oxidation reactions still remains largely unknown, which hinders the rational design and development of highly efficient carbon-based catalysts. Here we report a facile strategy for the synthesis of boron and nitrogen co-doped carbon nanosheet material (BNC), which exhibits excellent catalytic activity with 91% conversion and 99% selectivity in selective oxidation of benzyl alcohol into benzaldehyde, superior to those of traditional carbon materials (oxidized carbon nanotubes, graphites and commercial nanocarbons). Structural characterizations and kinetic measurements are studied to clarify the active site, in which phenolic hydroxyl on BNC is responsible for the production of benzaldehyde. Meanwhile, we put forward a possible reaction mechanism and point out the key factors in determining the reactivity for this reaction. Therefore, the present work provides new insight into structure-function relationships, paving the way for the development of highly efficient nanocarbon catalysts.

Thermomorphic behavior of the ionic liquids [C4mim][FeCl4] and [C12mim][FeCl4].

The iron-containing ionic liquids 1-butyl-3-methylimidazolium tetrachloroferrate(III) [C(4)mim][FeCl(4)] and 1-dodecyl-3-methylimidazolium tetrachloroferrate(III) [C(12)mim][FeCl(4)] exhibit a thermally induced demixing with water (thermomorphism). The phase separation temperature varies with IL weight fraction in water and can be tuned between 100 °C and room temperature. The reversible lower critical solution temperature (LCST) is only observed at IL weight fractions below ca. 35 % in water. UV/Vis, IR, and Raman spectroscopy along with elemental analysis prove that the yellow-brown liquid phase recovered after phase separation is the starting IL [C(4)mim][FeCl(4)] and [C(12)mim][FeCl(4)], respectively. Photometry and ICP-OES show that about 40 % of iron remains in the water phase upon phase separation. Although the process is thus not very efficient at the moment, the current approach is the first example of an LCST behavior of a metal-containing IL and therefore, although still inefficient, a prototype for catalyst removal or metal extraction.

Diversified applications of chemically modified 1,2-polybutadiene.

Commercially available 1,2-PB was transformed into a well-defined reactive intermediate by quantitative bromination. The brominated polymer was used as a polyfunctional macroinitiator for the cationic ring-opening polymerization of 2-ethyl-2-oxazoline to yield a water-soluble brush polymer. Nucleophilic substitution of bromide by 1-methyl imidazole resulted in the formation of polyelectrolyte copolymers consisting of mixed units of imidazolium, bromo, and double bond. These copolymers, which were soluble in water without forming aggregates, were used as stabilizers in the heterophase polymerization of styrene and were also studied for their ionic conducting properties.