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Abstract The applications of nanocarbon materials have been drawing an ever-increasing attention due to their unique physical and chemical properties. The performance of nanocarbon materials is determined or significantly influenced by their surface chemical composition and structure, including edges, holes, heteroatoms and functional groups etc. As a result, the accurate characterization and interpretation of the surface chemical properties of nanocarbon is extremely important, and numerous mature techniques were developed with the rapid progress of nanotechnology and characteristic instrumentation. In this review we summarized the latest development of characterization techniques for nanocarbon materials, the principles behind the techniques and the related data analysis methods. The characterization techniques are divided into four categories, including spectroscopy (IR, Raman, XPS, UPS, XAS, NMR and EELS), surface reaction (Boehm titration, potentiometric titration, chemical titration and TPSR), electron/probe microscopy (TEM, SEM, STM and AFM) and electro-chemistry methods. The most suitable application circumstances, test conditions and chemical information derivable by each characterization method are pointed out with examples, and the advantages and shortcomings of each technique are thoroughly discussed. We express the idea that full-scale structural information of nanocarbon could only be obtained by proper and comprehensive application of multiple kinds of characterization methods. [ABSTRACT FROM AUTHOR]

By using an alpha-amino acid as an interfacial protector and pH adjustor, we demonstrate the synthesis of the long-range ordered mesoporous alumina (OMA) via a modified solvent evaporation induced self-assembly (EISA) method. Characterization results of XRD, TEM, and N 2 adsorption-desorption indicate that the long-range highly ordered OMA was successfully obtained by using aluminum iso -propoxide as a precursor and Pluronic P123 as a template via the alpha-amino acid assisted EISA process. Moreover, by simply changing the alpha-amino acid, the textural property of the OMA was easily regulated, the extent of which depends on the molecular structure and coordination ability of the alpha-amino acid. The facile formation of the long-range highly ordered OMA was explained based on the function of the alpha-amino acids. [ABSTRACT FROM AUTHOR]

The varied surface structures of a Pd catalyst showed different catalytic performances in the partial hydrogenation of acetylene. The exposed Pd (1 0 0) facet is considered to be the most selective of all other facets for the formation of ethylene, but it is unstable and the fine structure needs to be revealed during the reaction. Herein, the evolution of the surface structure of cubic Pd nanoparticles, which are all bound with (1 0 0) facets, was studied by transmission electron microscopy in the partial hydrogenation of acetylene. Furthermore, the relation between the varying surface structure and the activity/selectivity was correlated. The (1 0 0) facets of Pd were transformed into stepped facets during the reaction, derived by adsorption/desorption of the reactants and energy compensation, which was the main reason for the decrease in the selectivity towards ethylene. [ABSTRACT FROM AUTHOR]

The ultimate objective of chemical conversion is to achieve 100 % selectivity from catalysis, and this is also a prodigious challenge for the conversion of light paraffins into olefins, because it involves controlled activation of highly stable aliphatic C−H bonds. Herein, we show that metal-free boron nitride (BN) nanosheets not only enable the oxidative dehydrogenation of ethane to ethylene exclusively at near 10 % conversion, but they also deliver a remarkable 60 % selectivity at an ethane conversion of 78 % and remain stable over 400 h at 575 °C. Our operando infrared spectroscopy and 18O isotope tracer study explicitly demonstrates that B−O(H) active sites are formed at the edges of BN through the aid of ethane, and the dehydrogenation circle is completed over these B−O sites by the assistance of O2. [ABSTRACT FROM AUTHOR]

The structures of PtNix nanoalloy particles were modified through thermal annealing in different atmospheres. The evolution of surface structures was uncovered by advanced transmission electron microscopy, and the structure–function correlation in methanol electro-oxidation was probed. It provided new insights into the design and synthesis of highly efficient electrocatalysts. [ABSTRACT FROM AUTHOR]

Non-precious metal catalysts as the electrocatalysts for oxygen reduction reaction (ORR) attract great attention due to their activity and stability close to Pt/C. Herein, the iron-based catalysts for ORR are synthesized through the heat treatment of o , m , p -phenylenediamine/iron/carbon precursors. Variation of polymerization, heat-treatment temperature, quantity and source of iron precursors during the synthesis of the catalyst leads to the difference in ORR activity. A relationship between the structure and performance is established through the systematic investigation of synthesis–structure–performance in these catalysts by using advanced characterization methods. It is confirmed that iron, nitrogen, and carbon play different roles in ORR activity, respectively. The formation and amount of Fe N complex, which are often proposed to be active sites for ORR, are consistent with species and environment of nitrogen and iron. [ABSTRACT FROM AUTHOR]

The complex (Mo,V)-based multicomponent M1 phase with a characteristic network of pentagonal, hexagonal, and heptagonal channels is the key catalyst for the catalytic oxidation from propane to acrylic acid. Herein, the atomic-scale structural dynamics in the orthorhombic Mo-V-Te-Nb oxide were probed under electron-beam stimulation. The recorded in situ scanning transmission electron microscopy images unravel the strong bonding and correlation between the (Mo,V)O6 octahedra and the central Nb moieties in the pentagonal channels. Such dynamic electron microscopy imaging can pave the way to chemically tailoring structural units of a general catalogue of functional polyoxo meta lates through applying top-down electron-beam probing. [ABSTRACT FROM AUTHOR]

Carbon is a unique and versatile element in nature that can form different architectures. Heteroatom (e.g., B, N, O, P, and S) modification has been proven to be an effective way to tailor the chemical and electrical properties of the carbon surface. Moreover, nanocarbons have been reported to be good supports for metal nanoparticles (NPs). It is essential to study the metal-support interaction between surface-modified carbon and metal NPs to understand performance. Advanced analytical transmission electron microscopy techniques are powerful tools that can be used to probe the metal-carbon support interaction in carbon-supported metal catalysts, as they can directly uncover local structures of the surface and the bulk of catalysts at the atomic scale and can also reveal chemical and electronic structural information that is related to their synthesis and catalytic properties significantly affecting their performance. Herein, several selected examples will be reviewed. [ABSTRACT FROM AUTHOR]

Employing anatase TiO2 nanocrystals with predominantly {0 0 1} facets, anatase TiO2 nanocrystals with predominantly {1 0 0} facets, and TiO2 P25 with predominantly {1 0 1} facets as supports, we have comprehensively studied the morphology effect of TiO2 on the Au-TiO2 interaction, structure, and catalytic performance of Au/TiO2 catalysts in C3H6 epoxidation with H2 and O2, C3H6 oxidation with O2, and H2 oxidation. A strong morphology-dependent interplay between the Au-TiO2 interaction and the catalyst structure was observed. Only Au nanoparticles were present in the Au/TiO2 catalysts and the Auδ− species was the largest in Au/TiO2{0 0 1} due to the creation of surface O vacancies of TiO2{0 0 1} upon Au loading, whereas the fraction of Auδ+ species was largest in Au/TiO2{1 0 0} due to the preserved surface stoichiometry of TiO2{1 0 0} upon Au loading. In H2 oxidation, Au/TiO2{1 0 0} with the largest fraction of Auδ+ species was the most active but least selective toward H2O2, whereas Au/TiO2{0 0 1} with the largest fraction of Auδ− species was the most selective toward H2O2. In C3H6 oxidation with O2, tiny C3H6 conversions with the formation of partial oxidation products were observed at low temperatures, whereas C3H6 combustion occurred at high temperatures. In C3H6 epoxidation with O2 and H2, the ensemble consisting of closely connected Auδ− and Ti4+ on anatase TiO2{0 0 1} and {1 0 1} facets with weak adsorption ability was the active structure and the Au/TiO2{0 0 1} catalyst containing the largest amount of this ensemble was the most active. These results demonstrated morphological engineering of oxides as an effective strategy to optimize the catalytic performance and understand the fundamentals of catalysis involving oxides. [ABSTRACT FROM AUTHOR]

A new concept of ionic liquid (IL) mono-dispersing catalyst on nanocarbon surface is presented. The liquid mixture of IL and model catalyst (1-octyl-3-methyl imidazolium phosphotungstate, OPW) on carbon nanotube is in a solid state which can be easily characterized and give a fundamental understanding of the interaction between the catalyst and the IL. The condensed IL is found to weaken the W=O bond of a catalyst that favours its interaction with an oxidizing agent that exhibited a reaction rate of 176 times to the performance of a single OPW during the oxidation of dibenzothiophene. Due to the heterogenization of this system, the catalyst can be easily recycled by a simple gravity separation. [ABSTRACT FROM AUTHOR]

Non-precious Fe/N co-modified carbon electrocatalysts have attracted great attention due to their high activity and stability in oxygen reduction reaction (ORR). Compared to iron-free N-doped carbon electrocatalysts, Fe/N-modified electrocatalysts show four-electron selectivity with better activity in acid electrolytes. This is believed relevant to the unique Fe-N complexes, however, the Fe-N structure remains unknown. We used o,m,p-phenylenediamine as nitrogen precursors to tailor the Fe-N structures in heterogeneous electrocatalysts which contain FeS and Fe3C phases. The electrocatalysts have been operated for 5000 cycles with a small 39 mV shift in half-wave potential. By combining advanced electron microscopy and Mössbauer spectroscopy, we have identified the electrocatalytically active Fe-N6 complexes (FeN6, [FeIII(porphyrin)(pyridine)2]). We expect the understanding of the FeN6 structure will pave the way towards new advanced Fe-N based electrocatalysts. [ABSTRACT FROM AUTHOR]

Non-precious Fe/N co-modified carbon electrocatalysts have attracted great attention due to their high activity and stability in oxygen reduction reaction (ORR). Compared to iron-free N-doped carbon electrocatalysts, Fe/N-modified electrocatalysts show four-electron selectivity with better activity in acid electrolytes. This is believed relevant to the unique Fe-N complexes, however, the Fe-N structure remains unknown. We used o,m,p-phenylenediamine as nitrogen precursors to tailor the Fe-N structures in heterogeneous electrocatalysts which contain FeS and Fe3C phases. The electrocatalysts have been operated for 5000 cycles with a small 39 mV shift in half-wave potential. By combining advanced electron microscopy and Mössbauer spectroscopy, we have identified the electrocatalytically active Fe-N6 complexes (FeN6, [FeIII(porphyrin)(pyridine)2]). We expect the understanding of the FeN6 structure will pave the way towards new advanced Fe-N based electrocatalysts. [ABSTRACT FROM AUTHOR]

It is crucial to accurately describe the interaction between the surface functionality and the supported metal catalyst because it directly determines the activity and selectivity of a catalytic reaction. It is, however, challenging with a metal-carbon catalytic system owing to the ultrafine feature, instability, and subtle response of the components upon application of an external field. Herein, we use in situ TEM, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy techniques to record the interaction in palladium on carbon nanotubes (CNTs) from room temperature to 600?°C. We focus on probing the effects of oxygen and nitrogen-containing functional groups on supported palladium nanoparticles (NPs) in the model catalytic system. The stability of palladium NPs supported on CNTs depends strongly on the surface properties of CNTs. Moreover, the oxygen-containing functional groups on the CNT surfaces, such as carboxylic acids and anhydrides, have an even stronger interaction with palladium NPs than the nitrogen-containing counterparts. Our work contributes to elucidation of the complex metal-carbon interaction and unlocks potential in activity and selectivity control of these catalytic systems. [ABSTRACT FROM AUTHOR]

Abstract: Electron microscopy (EM) enables us, not only to reveal the morphology, but also to provide structural, chemical and electronic information about solid catalysts at the atomic level, providing a dramatic driving force for the development of heterogeneous catalysis. Almost all catalytic materials have been studied with EM in order to obtain information about their structures, which can help us to establish the synthesis–structure–property relationships and to design catalysts with new structures and desired properties. Herein, several examples will be reviewed to illustrate the investigation of catalytic materials by using electron beams. [Copyright &y& Elsevier]

What not to wear: This work illustrates the clothing of 1 D carbon nanotubes at desired locations with nanoengineered metal nanostructures in a ring pattern for nanodevice applications, such as catalysis. [ABSTRACT FROM AUTHOR]

EDX marks the spot: STEM‐EDX mapping is a highly useful tool for studying advanced catalytic materials. Beam intensity and dwell time can be adjusted to an optimum balance for obtaining an unambiguous elemental map. [ABSTRACT FROM AUTHOR]

Abstract: Zeolite supported metal catalysts are widely used while the electron beam sensitive zeolite makes the characterization of the catalysts using electron microscope (EM) very difficult. Herein a sacrificial-zeolite specimen preparation (SZSP) technique is developed for the EM analysis of the catalyst. The metal particles are transferred from the zeolite support to the deposited nanocarbon generated in the metal catalyzed hydrocarbon reaction. SAPO-34 zeolite with Al2O3 binder supported Pt catalyst is employed as the model catalyst. The propane dehydrogenation reaction is carried out to deposit the nanocarbon overlayer which the Pt particles are transferred to as the new support for EM observation. The original catalyst, the deposited nanocarbon, as well as the Pt particles on the new support are characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, thermogravimetry/differential thermal analysis, Raman spectrometry, and scanning transmission electron microscope. The nanocarbon deposited on SAPO-34 and Al2O3 are of different morphologies and structures. The as-observed distribution of Pt particles on the new support suggests the enrichment of Pt on SAPO-34. The shape and size of the Pt particles as well as the strong Pt–SAPO-34 interaction are directly observed. [Copyright &y& Elsevier]

More than scratching the surface: The mechanism by which supported Pd nanoparticles (PdNPs) catalyze cross‐coupling reactions is the subject of debate. The changes in supported PdNPs during coupling reactions are studied by exploiting modified carbon nanotubes (CNTs) as support materials. After catalysis, CNTs with scratched walls and PdNPs with surface crystalline distortions were discovered, offering insights into the catalytic mechanism. [ABSTRACT FROM AUTHOR]

Die Katalysemechanismen für Kreuzkupplungen an Pd ‐ Nanopartikeln (PdNPs) auf Trägersubstraten sind umstritten. Dynamische Veränderungen an Nanopartikeln während solcher Kupplungsreaktionen wurden für PdNPs auf modifizierten Kohlenstoff ‐ Nanoröhren (CNTs) als Träger verfolgt. Die gut dispergierbaren Pd ‐ CNTs können mit den Reaktanten in der Reaktionslösung codispergieren und somit den molekularen Kontakt sowie die Reaktivität in der Oberflächenkatalyse erhöhen. [ABSTRACT FROM AUTHOR]

A series of gallia-supported Pd-Ga catalysts that consist of metallic nanoparticles on three porous polymorphs of Ga2O3 (α-, β-, and γ-Ga2O3) were synthesized by a controlled co-precipitation of Pd and Ga. The effects of formation of Ga-Pd intermetallic compounds (IMCs) were studied in four catalytic reactions: methanol steam reforming, hydrogenation of acetylene, and methanol synthesis by CO and CO2 hydrogenation reactions. The IMC Pd2Ga forms upon reduction of α- and β-Ga2O3-supported materials in hydrogen at temperatures of 250 and 310 °C, respectively. At higher temperatures, Ga-enrichment of the intermetallic particles is observed, leading to formation of Pd5Ga3 before the support itself is reduced at temperatures above 565 °C. In the case of Ga-Pd/γ-Ga2O3, no information about the metal particles could be obtained owing to their very small size and high dispersion; however, the catalytic results suggest that the IMC Pd2Ga also forms in this sample. Pd2Ga/gallia samples show a stable selectivity towards ethylene in acetylene hydrogenation (≈75 %), which is higher than for a monometallic Pd reference catalyst. An even higher selectivity of 80 % was observed for Pd5Ga3 supported on α-Ga2O3. In methanol steam reforming, the Ga-Pd/Gallia catalysts showed, in contrast to Pd/Al2O3, selectivity towards CO2 of up to 40 %. However, higher selectivities, which have been reported for Pd2Ga in literature, could not be reproduced in this study, which might be a result of particle size effects. The initially higher selectivity of the Pd5Ga3-containing samples was not stable, suggesting superior catalytic properties for this IMC, but that re-oxidation of Ga species and formation of Pd2Ga occurs under reaction conditions. In methanol synthesis, CO hydrogenation did not occur, but a considerable methanol yield from a CO2/H2 feed was observed for Pd2Ga/α-Ga2O3. [ABSTRACT FROM AUTHOR]

Abstract: Uniformly dispersed ruthenium nanoparticles supported on non-functional carbon nanotubes (CNT) have been successfully synthesized by using a facile and solvent-free microwave-assisted thermolytic method with dodecacarbonyltriruthenium as the precursor. The results show that 2–4nm sized spheres of Ru nanoparticles were uniformly dispersed and supported on non-functional CNT by several minutes'' exposure to microwave irradiation without solvent. The Ru/CNT catalysts show the desired conversion of about 80% and selectivity to hydrocinnamaldehyde of about 72% in the selective hydrogenation of cinnamaldehyde, where the catalytic performance has been found to depend on both the Ru loading and the surface properties of CNT. [Copyright &y& Elsevier]

Abstract: Nanostructured nickel silicides have been prepared by reduction and silicification of high-surface-area nickel oxide (145m2 g−1) produced via precipitation. The prepared materials were characterized by nitrogen adsorption, X-ray diffraction, thermal analysis, FT-IR spectroscopy, scanning electron microscopy, transmission electron microscopy, magnetic and electrochemical measurements. The nickel silicide formation involves the following sequence: NiO (cubic)→Ni (cubic)→Ni2Si (orthorhombic)→NiSi (orthorhombic)→NiSi2 (cubic), with particles growing from 13.7 to 21.3nm. The nickel silicides are ferromagnetic at room temperature, and their saturation magnetization values change drastically with the increase of Si content. Nickel silicides have remarkably low electrical resistivity and noble metal-like properties because of a constriction of the Ni d band and an increase of the electronic density of states. The results suggest that such silicides are promising candidates as inexpensive yet functional materials for applications in electrochemistry as well as catalysis. [Copyright &y& Elsevier]

Abstract: A family of unsupported NiMoW sulfide catalysts have been prepared by thermal decomposition of mechanically ground tetramethylammonium thiomolybdotungstate and Ni(NO3)2 for hydrodesulfurization of dibenzothiophene. The materials were characterized by Fourier transformation infrared spectroscopy, ultraviolet–visible spectroscopy, thermogravimetric analysis, X-ray diffraction, N2 physorption, scanning electron microscopy, and transmission electron microscopy. The results showed that structures and properties of unsupported NiMoW sulfides depend on nickel content and decomposition condition. XRD revealed a decrease in the stacking along the c direction of the MoS2 and/or WS2 crystalline structures as the nickel content was increased, consistent with a higher dispersion of the metal sulfides observed by electron microscopy. The low nickel content in Ni0.5MoWS y catalyst gave a positive effect on the hydrodesulfurization of dibenzothiophene, as indicated by the greatly increased specific catalytic activity per unit surface area. In contrast, the high nickel content in Ni1.5MoWS y catalyst showed a negative effect due to the formation of nickel sulfides. Ni0.5MoWS y catalyst showed the highest activity in the hydrodesulfurization reaction compared to other samples. The results further suggest that unsupported NiMoW sulfide catalysts may be promising candidates for wide application in hydrotreating of fuel oil. [Copyright &y& Elsevier]

Abstract: Bi2Sr2CaCu2O8+δ (Bi2212) thin film is an important superconducting material ascribed to its high transition temperatures and low toxicity, but the application of Bi2212 thin films is limited due to the appearances of intergrowth and impurity phases. To achieve high-quality Bi2212 thin film by molecular beam epitaxy (MBE), the oxidizing gas pressure and substrate temperature are the key parameters. Here, the phase formation in Bi-based thin films grown by MBE was studied as a function of oxidizing gas pressure and substrate temperature. Furthermore, the thermodynamic parameters have been investigated through enthalpy change. This study indicates that the substrate temperature was increased with the enhancing of ozone partial pressure when the composition ratio is fixed, Bi2212 single phase can be formed. Moreover, the chemical stability decreases in the order of Bi2Sr2CuO6+δ >Bi2212>Bi2Sr2Ca2Cu3O10+δ . [Copyright &y& Elsevier]

• A novel electronic modulation strategy on metal-free catalyst via organic modification was proposed. • The electron transfer effect was well proved and the electron transfer direction was clarified. • A deep oxidative desulfurization can be achieved with the residual sulfur content less than 10 ppm. • The mechanism of the improved catalytic activity was illustrated clearly. Tuning electronic structure of metal catalysts by organic modification is an efficient strategy for domination of their catalytic performances. However, the electronic structure tuning over metal-free catalysts remains to be a challenge. In this work, an organic modification strategy with deep eutectic solvents (DES) as organic modifier over metal-free catalysts was proposed to tune the electronic structure of hexagonal boron nitride (h-BN). Detailed experiments showed that the electronic properties of h-BN was rationally tuned by the introduced DES, in which the B atoms in h-BN were positively charged. Meanwhile, the modulated electronic properties can lower the activation energy for the generation of hydroxyl radicals (•OH) from hydrogen peroxide (H 2 O 2), thus leading to a promoted catalytic performance in oxidative desulfurization. This finding may pave a new strategy for tuning metal-free catalysts with highly-active catalytic performance. An organic ligand modification strategy over metal-free boron nitride catalyst. [Display omitted] [ABSTRACT FROM AUTHOR]

No matter how you slice it: New insight into nanostructured materials is provided by a novel imaging technique, which reproduces the real three‐dimensional (3D) fine structure of nanomaterials at the atomic level from two‐dimensional (2D) projections (see scheme). [ABSTRACT FROM AUTHOR]

Salamitaktik zur Strukturaufklärung: Ein neuer Einblick in nanostrukturierte Materialien wird durch eine neuartige Abbildungstechnik gegeben, welche die reale dreidimensionale (3D ‐ )Feinstruktur auf atomarer Ebene mithilfe herkömmlicher zweidimensionaler (2D ‐ )Projektionen rekonstruiert (siehe schematische Darstellung). [ABSTRACT FROM AUTHOR]

Positively charged bulk Au particles with size of 20–150 nm were formed on amino-modified porous polydivinylbenzene (Au/PN), which showed superior catalytic performance and good recyclability in the aerobic oxidation of styrene. [ABSTRACT FROM AUTHOR]

[Display omitted] How to construct a new electrode/electrolyte interface structure in solid-state batteries (SSBs), enhance interface stability, and improve the cycling performance of SSBs is a great challenge for the development of SSBs. Here, an all-in-one "interface-free" structure was developed. This interfacial structure constructs a full-interface hydrogen bonding network through the abundant hydrogen bond donors and acceptors in the cathode and electrolyte to enhance the interfacial stability and avoid interfacial failure during charging and discharging, and generates cathode–electrolyte interface (CEI) in-situ to effectively regulate zinc ion transport. Square cells assembled in this structure are stabilized for 100 cycles at a current density of 0.1 mA cm−2. This integrated electrode provides a new idea for the long stable cycle of SSBs. [ABSTRACT FROM AUTHOR]

Constructing an ultra‐long‐lived red thermally activated delayed fluorescence carbon dots (TADF‐CDs) with time‐dependent phosphorescence colors (TDPC) in both solid and aqueous is still a challenge. Herein, a red TADF‐CDs, constructed via. a modified solid‐state pyrolysis strategy, show the phosphorescence emissions at 595, 670, and 725 nm with the afterglow lifetime longer than most of reported red TADF‐materials. In addition, the resulting CDs trigger the TDPC activity while the emission colors changed from red to green both in solid state and in aqueous suspension. The synergistic effects of boron‐hybridization in the seed CDs and the additional C═O groups generated in urea‐assisted pyrolysis, result in a stronger spin‐orbit coupling (SOC) between the 1(n, π*) and the 3(π, π*), the mitigated energy gap (ΔEST) and the non‐radiative relaxations of triplet excited states. The TDPC performance endow the resulting TADF‐CDs the usability in advance information security with enhanced‐security‐level encryption strategy. [ABSTRACT FROM AUTHOR]

A key task in today's inorganic synthetic chemistry is to develop effective reactions, routes, and associated techniques aiming to create new functional materials with specifically desired multilevel structures and properties. Herein, we report an ultrathin two‐dimensional layered composite of graphene ribbon and silicate via a simple and scalable one‐pot reaction, which leads to the creation of a novel carbon‐metal‐silicate hybrid family: carbosilicate. The graphene ribbon is in situ formed by unzipping carbon nanotubes, while the ultrathin silicate is in situ obtained from bulk silica or commercial glass; transition metals (Fe or Ni) oxidized by water act as bridging agent, covalently bonding the two structures. The unprecedented structure combines the superior properties of the silicate and the nanocarbon, which triggers some specific novel properties. All processes during synthesis are complementary to each other. The associated synergistic chemistry could stimulate the discovery of a large class of more interesting, functionalized structures and materials. [ABSTRACT FROM AUTHOR]

A key task in today's inorganic synthetic chemistry is to develop effective reactions, routes, and associated techniques aiming to create new functional materials with specifically desired multilevel structures and properties. Herein, we report an ultrathin two‐dimensional layered composite of graphene ribbon and silicate via a simple and scalable one‐pot reaction, which leads to the creation of a novel carbon‐metal‐silicate hybrid family: carbosilicate. The graphene ribbon is in situ formed by unzipping carbon nanotubes, while the ultrathin silicate is in situ obtained from bulk silica or commercial glass; transition metals (Fe or Ni) oxidized by water act as bridging agent, covalently bonding the two structures. The unprecedented structure combines the superior properties of the silicate and the nanocarbon, which triggers some specific novel properties. All processes during synthesis are complementary to each other. The associated synergistic chemistry could stimulate the discovery of a large class of more interesting, functionalized structures and materials. [ABSTRACT FROM AUTHOR]

Ni‐promoted electrocatalytic biomass reforming has shown promising prospect in enabling high value‐added product synthesis. Here, we developed a novel hybrid catalyst with Ni nanosheet forests anchored on carbon paper. The hybrid catalyst exhibits high efficiency in electrooxidation of HMF to FDCA coupling with H2 production in high purity. The Ni nanosheets have small crystal grain sizes with abundant edges, which is able to deliver an efficient HMF oxidation to FDCA (selectivity >99 %) at low potential of 1.36 VRHE with high stability. The post‐reaction structure analysis reveals the Ni nanosheets would transfer electrons to carbon and readily turn into NiOx and Ni(OH)x during the reaction. DFT results suggest high valence Ni species would facilitate the chemical adsorption (activation) of HMF revealing the reaction pathway. This work emphasizes the importance of the precise control of Ni activity via atomic structure engineering. [ABSTRACT FROM AUTHOR]

Ni‐promoted electrocatalytic biomass reforming has shown promising prospect in enabling high value‐added product synthesis. Here, we developed a novel hybrid catalyst with Ni nanosheet forests anchored on carbon paper. The hybrid catalyst exhibits high efficiency in electrooxidation of HMF to FDCA coupling with H2 production in high purity. The Ni nanosheets have small crystal grain sizes with abundant edges, which is able to deliver an efficient HMF oxidation to FDCA (selectivity >99 %) at low potential of 1.36 VRHE with high stability. The post‐reaction structure analysis reveals the Ni nanosheets would transfer electrons to carbon and readily turn into NiOx and Ni(OH)x during the reaction. DFT results suggest high valence Ni species would facilitate the chemical adsorption (activation) of HMF revealing the reaction pathway. This work emphasizes the importance of the precise control of Ni activity via atomic structure engineering. [ABSTRACT FROM AUTHOR]

Die Kenntnis der Struktur katalytisch aktiver Spezies/Phasen und die Bereitstellung von Methoden zu ihrer gezielten Herstellung sind zwei Voraussetzungen für die Entwicklung von Katalysatoren mit der gewünschten Performance. Hierin stellen wir eine einfache Methode zur präzisen Herstellung von Träger‐/Vollkatalysatoren vor. Diese Methode nutzt die Eigenschaft von Metalloxiden, bei Behandlung in wässrigen Ammoniaklösungen lösbar zu sein und gleichzeitig ausgefällt werden zu können. Bei Anwendung dieser Methode auf einen herkömmlichen VOx−Al2O3‐Katalysator wurde die Konzentration koordinativ ungesättigter Al‐Zentren einfach durch Änderung des pH‐Werts der Lösung eingestellt. Diese Stellen beeinflussen die Stärke der V−O−Al‐Bindungen isolierter VOx‐Spezies und damit deren Reduzierbarkeit. Diese Methode ist auch zur Steuerung der Reduzierbarkeit von Vollkatalysatoren anwendbar, wie am Beispiel eines CeO2−ZrO2−Al2O3‐Systems gezeigt wurde. Die Einsetzbarkeit der entwickelten Katalysatoren wurde in der oxidativen Dehydrierung von Ethylbenzol zu Styrol mit CO2 und in der nichtoxidativen Propandehydrierung zu Propen bestätigt. Unser Ansatz lässt sich auf die Herstellung beliebiger Metalloxidkatalysatoren, die in einer Ammoniaklösung löslich sind, ausweiten. [ABSTRACT FROM AUTHOR]

Knowing the structure of catalytically active species/phases and providing methods for their purposeful generation are two prerequisites for the design of catalysts with desired performance. Herein, we introduce a simple method for precise preparation of supported/bulk catalysts. It utilizes the ability of metal oxides to dissolve and to simultaneously precipitate during their treatment in an aqueous ammonia solution. Applying this method for a conventional VOx−Al2O3 catalyst, the concentration of coordinatively unsaturated Al sites was tuned simply by changing the pH value of the solution. These sites affect the strength of V−O−Al bonds of isolated VOx species and thus the reducibility of the latter. This method is also applicable for controlling the reducibility of bulk catalysts as demonstrated for a CeO2−ZrO2−Al2O3 system. The application potential of the developed catalysts was confirmed in the oxidative dehydrogenation of ethylbenzene to styrene with CO2 and in the non‐oxidative propane dehydrogenation to propene. Our approach is extendable to the preparation of any metal oxide catalysts dissolvable in an ammonia solution. [ABSTRACT FROM AUTHOR]

Strong metal‐support interaction (SMSI) greatly improves the performances of various supported metal nanoparticle catalysts. Classical SMSI relies on the oxide species with substoichiometric oxygen concentration, which prefers to retreat off in humid and oxidative atmospheres. A SMSI is reported with oxygen‐saturated overlayers on Au/TiO2 catalyst achieved by steaming treatment, an opposite condition to the classical SMSI formation. Through a combination of experimental and theoretical methods, this study demonstrates that the strong interactions between the TiOxHy (x≥2) species and Au surface cause the support migration to encapsulate Au nanoparticles. The oxygen‐saturated oxide overlayers are stable in oxidative, reductive, and humid atmospheres, providing great vitality to stabilize metal nanoparticle catalysts under varied and complex reaction conditions to outperform the classical SMSI. [ABSTRACT FROM AUTHOR]

Cartography for the catalysis researcher The cover picture shows that the observation of individual elements in advanced catalytic materials can be achieved by determining optimum conditions for obtaining an accurate STEM‐EDX elemental map. In their Communication on p. 2586 ff., D. S. Su et al. reveal that a suitable combination of dwell time and beam intensity is crucial in pinpointing elemental distribution by using STEM‐EDX mapping. Importantly, trace amounts of catalytic species can be observed towards the analytical limit to determine information, such as elemental composition, size, and morphology, as well as, in particular, the possible dynamic changes in nanoparticles after catalytic reactions. [ABSTRACT FROM AUTHOR]

Here, we report a new strategy for the construction of a peptide nucleic acid–microRNA nanocomplex with dual function to simultaneously suppress oncogenic microRNAs and upregulate tumor-suppressive microRNAs in target cancer cells. [ABSTRACT FROM AUTHOR]

Review: 69 refs. [ABSTRACT FROM AUTHOR]

Review: 80 refs. [ABSTRACT FROM AUTHOR]

Carbon coating has been attracting wide interests as optimum protection technology for Li ion batteries. Recently, carbon-coating has been considered as effective modification for copper/aluminum current collector. Although rate performance and lifetime of electrodes have been widely investigated, interfacial insight remains very superficial, hampering considerable improvement of electrode performance. Here we propose mechanistic models of double interfaces: one interface locates between Cu and active materials, and the other is referred to as solid electrolyte interphase (SEI) film coating on the current collector. Then vertical graphene nanowalls coated copper (VG) was prepared to reduce interfacial resistance of SEI film derived from an amorphous carbon coating layer. As a result, it exhibited a good rate performance with ∼190 mAh/g at 3 C, in contrast with ∼160 mAh/g for commercial carbon-coated copper (CC) and ∼90 mAh/g for traditional bare copper (BC). [ABSTRACT FROM AUTHOR]

Supported metal catalysts play a central role in the modern chemical industry but often exhibit poor on-stream stability. The strong metal-support interaction (SMSI) offers a route to control the structural properties of supported metals and, hence, their reactivity and stability. Conventional wisdom holds that supported Au cannot manifest a classical SMSI, which is characterized by reversible metal encapsulation by the support upon high-temperature redox treatments. We demonstrate a classical SMSI for Au/TiO2, evidenced by suppression of CO adsorption, electron transfer from TiO2 to Au nanoparticles, and gold encapsulation by a TiOx overlayer following high-temperature reduction (reversed by subsequent oxidation), akin to that observed for titania-supported platinum group metals. In the SMSI state, Au/TiO2 exhibits markedly improved stability toward CO oxidation. The SMSI extends to Au supported over other reducible oxides (Fe3O4 and CeO2) and other group IB metals (Cu and Ag) over titania. This discovery highlights the general nature of the classical SMSI and unlocks the development of thermochemically stable IB metal catalysts. [ABSTRACT FROM AUTHOR]

The typical industrial catalyst used for methanol synthesis is a multi‐component catalyst based on Cu/ZnO/Al2O3. The synergies between various phases of this catalyst play a vital role in defining the overall catalytic function and performance. To gain insights into the role and interaction between the relevant components and phases, ex situ and in situ transmission electron microscopy (TEM) was deployed to investigate the structures and phases of an industrial Cu/ZnO/Al2O3 in its precursor, activated and reaction states. High structural inhomogeneity in this material is revealed, i. e. the presence of various phases with different morphologies and compositions. It is shown how structural and compositional changes occur during hydrogen treatment and how compositional inhomogeneity in the starting material translates into differences in the local composition of the activated and working catalyst. The formation of defective metallic copper particles (stacking faults and twins) that are in an intimate contact with zinc oxide (poorly crystalline, partially reduced ZnOx and crystalline ZnO), alumina, Zn−Al oxide and carbon‐zinc‐oxygen containing phases (such as zinc formate) is observed. It is also uncovered that alumina plays a potentially important role in stabilizing cationic zinc species. This work provides atomic‐level insight into the relevant state of an industrial methanol synthesis catalyst and the associated synergistic interplay between the involved phases in reactive atmosphere. [ABSTRACT FROM AUTHOR]

The hetero‐photocatalysts in hollow structure may provide more dispersive reactive sites, the easily accessible open channel for substrates and the intensive visible light harvest ability, which have shown evidently promoting photocatalytic efficiency. Herein, a novel photocatalyst ZIS/Co3S4HLs in hierarchical hollow heterostructure has been constructed by epitaxially growing 2D ZnIn2S4 (ZIS) nanosheets on Co‐ZIF‐L‐derived Co3S4 hollow leaves (Co3S4HLs). The formation of the Schottky junction has promoted the photogenerated charges transfer, which is well proven by the electrochemical analyses and the DFT calculation. It is suggested that both constructed hierarchical hollow heterostructure and the Schottky junction with well‐matched band potentials are responsible for the remarkable H2 evolution rates under the visible light irradiation, which are much higher than most of the reported results by other ZIS‐based composite photocatalysts. The good cyclic photocatalytic activity and structural stability of these hierarchical hollow leaves provide new insight into designing a high‐efficient heterostructure being used in solar energy conversion. [ABSTRACT FROM AUTHOR]

The intercalation of guest molecules into layered materials is an important strategy to develop multifunctional hybrid nanocomposites and porous materials. The unique mesoporous structure and the intrinsic acidity of metal oxide intercalated porous clay heterostructure (PCH) make it a promising catalytic material. In contrast to the current synthesis methods of PCH that have complex procedures and structure-controlling difficulties, a novel one-step approach with supercritical CO 2 (scCO 2 ) as medium was invented using montmorillonite (Mt) as the host matrix and cetyltrimethylammonium bromide as the structure-directing agent (SDA). In this simple and efficient approach, the high diffusivity of scCO 2 ensures the facile transportation of cationic SDA into the interlayer space of Mt via ion exchange, which eliminates a requirement for the high solubility of a SDA in scCO 2 . As a result, the co-assembly of the SDA and the oxide precursor controlled in the interlayer space of Mt leads to the highly ordered PCH. Furthermore, this unique approach provides a general technique to synthesize multi-functional intercalation compounds. [ABSTRACT FROM AUTHOR]

Nitrogen-doped nanocarbon materials as metal-free electrocatalysts for the oxygen reduction reaction (ORR) have attracted great attention, owing to their catalytic activity close to Pt/C in alkaline media. Annealed nanodiamonds (AND) possess a special structure, because we can finely control the carbon sp2/sp3 ratio. This provides a good opportunity to study the relationship between ORR performance (activity and stability) and the special structure of AND. We have used nitrogen-doped annealed nanodiamonds (NAND) with varied carbon sp2/sp3 ratio as metal-free electrocatalysts for ORR in alkaline media. NAND showed higher catalytic activity for ORR with higher content of sp2 carbon and larger amount of nitrogen species present as pyridinic groups. More importantly, NAND displayed stability superior to other nitrogen-doped nanocarbon materials as a result of transformation of carbon from sp3 to sp2 during electrochemical cycling. [ABSTRACT FROM AUTHOR]

The Pd/HS-1 catalyst with hollow hexagonal prism structure was prepared and applied to Suzuki coupling reaction, achieving over 99% conversion of bromobenzene in a short period of time. [Display omitted] • Hierarchical porous zeolites were prepared by dissolution recrystallization and then loaded with Pd nanoparticles by impregnation. • The proper acid sites as well as metal-zeolite interactions can modulate the electronic state of Pd, and thus improve the conversion of bromobenzene. • The size of metal nanoparticles plays a decisive role in metal-catalyzed heterogeneous reactions, due to Pd binding energy varied with changed sizes. • 2.0Pd/HS-1 provides excellent catalytic performance in non-toxic reaction media, mild reaction conditions, and short reaction times while achieving recyclability. The Suzuki-Miyaura reaction is one of the most effective routes for the construction of carbon–carbon bonds, due to the obvious advantages of mild reaction conditions, wide range of functional group tolerance, simplicity of operation, and environmental friendliness. However, these reactions highly depend on the development of the active and stable catalysts. Herein, the hollow hexagonal prismatic silicalite-1 (HS-1) zeolite-supported palladium nanoparticles (Pd NPs) were synthesized and applied as a catalyst in Suzuki-Miyaura reaction. The experimental results show that 2.0Pd/HS-1 is an efficient and stable catalyst, which can achieve a high conversion rate (>99.9 %) in a short time (45 min) and can be recycled. Further studies show that 2.0Pd/HS-1 has abundant mesopores, which are favorable for exposing more active sites and promoting the transfer of reactants around the catalysts, thus improving the contact opportunities between the catalysts and the feedstock. Moreover, its proper acid sites as well as metal-zeolite interactions can modulate the electronic state of Pd, and thus improve the conversion of bromobenzene. This work provides new insights into the design, synthesis and applications of highly efficient hollow silicalite-1 zeolite loaded metal catalysts. [ABSTRACT FROM AUTHOR]

In this work, we report a carbon-mediated strategy to construct supported Co-MnO x nano-interfacial catalyst that enables highly selective synthesis of long-chain linear α-olefins (C 5+ =) via the Fischer-Tropsch (FT) reaction. The co-impregnation of glucose as the carbon precursor and metal salt aqueous solution over SiO 2 followed by pyrolysis and oxidation creates a catalyst with stable and rich Co-MnO x nano-interfaces after reduction and under FT conditions, which are convincingly revealed from characterizations of the catalysts at different stages. The optimal catalyst is stable for over 400 h without an observably decreased CO conversion, and the highest space-time yield of C 5+ = is achieved to be 0.79 g·g Co −1·h−1, which are mainly originated from the suppressed sintering of metallic Co and favored CO adsorption/dissociation with a reasonably inhibited H 2 co-adsorption. The simple procedure and broad availability of precursors make our developed strategy a practically important surface-engineering method capable of precisely fabricating stable nano-interfacial catalysts. [Display omitted] • Carbon-mediated method is explored for constructing Co-MnO x nano-interfacial catalyst. • The developed Co-MnO x catalyst is highly active and stable for Fischer-Tropsch reaction. • STY of 0.79 g·g Co −1·h−1 for C 5+ olefins is achieved over the optimal Co-MnO x catalyst. • Maximized Co-MnO x perimeter facilitates a high surface coverage ratio of CO* (C*)/H*. [ABSTRACT FROM AUTHOR]