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It has been known that plastics with undegradability and long half-times have caused serious environmental and ecological issues. Considering the devastating effects, the development of efficient plastic upcycling technologies with low energy consumption is absolutely imperative. Catalytic hydrogenolysis of single-use polyethylene over Ru-based catalysts to produce high-quality liquid fuel has been one of the current top priority strategies, but it is restricted by some tough challenges, such as the tendency towards methanation resulting from terminal C-C cleavage. Herein, we introduced Ru nanoparticles supported on hollow ZSM-5 zeolite (Ru/H-ZSM-5) for hydrocracking of high-density polyethylene (HDPE) under mild reaction conditions. The implication of experimental results is that the 1Ru/H-ZSM-5 (~1 wt % Ru) acted as an effective and reusable bifunctional catalyst providing higher conversion rate (82.53 %) and liquid fuel (C 5 -C 21 ) yield (62.87 %). Detailed characterization demonstrated that the optimal performance in hydrocracking of PE could be attributed to the moderate acidity and appropriate positively charged Ru species resulting from the metal-zeolite interaction. This work proposes a promising catalyst for plastic upcycling and reveals its structure-performance relationship, which has guiding significance for catalyst design to improve the yield of high-value liquid fuels., (© 2024 Wiley-VCH GmbH.)

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., (© 2023 Wiley-VCH GmbH.)

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 VO x -Al 2 O 3 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 VO x species and thus the reducibility of the latter. This method is also applicable for controlling the reducibility of bulk catalysts as demonstrated for a CeO 2 -ZrO 2 -Al 2 O 3 system. The application potential of the developed catalysts was confirmed in the oxidative dehydrogenation of ethylbenzene to styrene with CO 2 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., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Catalysis is regarded as an effective strategy to fundamentally increase sulfur utilization, accelerating the kinetics of the transformation between lithium polysulfides (LiPSs) and lithium sulfide (Li 2 S) on a substrate. However, the intermodulation of catalysts and sulfur species is elusive, which is limited to the comprehensive analysis of electrochemical performance in the dynamic reaction process. Herein, cobalt nanoparticles loaded on MXene nanosheets (Co/Ti 2 C) are selected as sulfur hosts and the representative catalyst. By combining ex situ electrochemical results and interfacial structural chemical monitoring, the catalysis process of Co/Ti 2 C toward LiPSs conversion is revealed, and the outstanding performance originates from the optimization of chemical adsorption, catalytic activity, and lithium-ion transfer behaviors, which is based on electronic/ion modulation and sufficient interfaces among catalysts and electrolyte. This work can guide the construction of electronic modulation at triple-phase interface catalysis to overcome the shuttle effect and facilitate sulfur redox kinetics in Li-S batteries., (© 2022 Wiley-VCH GmbH.)

A novel electrochemically assisted cycloaddition process is proposed, in which highly efficient coupling of CO 2 with styrene oxide (SO) can be achieved to form styrene carbonate (SC) as a high-value-added product. A series of Cu catalysts with different morphologies and chemical states were fabricated on carbon paper (CP) by using in-situ electrodeposition, and the sample with nano-dendrimer structure was found to exhibit a relatively high activity of 74.8 % SC yield with 92.7 % SO conversion under gentle reaction conditions, thus showing its potential for practical applications. The relatively high electrochemically active surface area and charge transfer ability of dendrimer-like Cu benefited the electrochemical reaction. In particular, the Cu 2+ species that were formed in situ during the reaction played a vital role in enhancing the activity and selectivity of the proposed Cu/CP hybrid catalyst. Cu 2+ atoms served as active sites that can not only electrochemically activate CO 2 but also facilitate the ring opening of SO. Mechanistic analysis suggested that the reaction followed electrochemical and liquid-phase heterogeneous paths, which provide a new green and sustainable route for efficient utilization of CO 2 resources for fine chemical electrosynthesis., (© 2022 Wiley-VCH GmbH.)

Selective hydrogenation of substituted nitroaromatic compounds is an extremely important and challenging reaction. Supported metal catalysts attract much attention in this reaction because the properties of metal nanoparticles (NPs) can be modified by the nature of the support. Herein, the support morphology on the catalytic performance of selective hydrogenation of 3-nitrostyrene to 3-vinylaniline was investigated. Pt NPs supported on octadecahedral α-Fe 2 O 3 supports with a truncated hexagonal bipyramid shape (Pt/α-Fe 2 O 3 -O) and rod-shaped α-Fe 2 O 3 supports (Pt/α-Fe 2 O 3 -R) were prepared by glycol reduction method. Detailed characterizations reveal that the electronic structure and dispersion of Pt NPs can be modified by the supports. The Pt/α-Fe 2 O 3 -O catalyst exhibited superior catalytic performance for hydrogenation of 3-nitrostyrene because of its low coordinated Pt sites and the small Pt NPs size, which is benefit from the high-index exposed surfaces of truncated hexagonal bipyramid-shaped α-Fe 2 O 3 support. The structural evolution during the catalytic reaction was investigated in detail by identical location transmission electron microscopy (IL-TEM) method, which found that the high cycling activity of Pt/α-Fe 2 O 3 -O catalyst during the cycle experiment results from the stability of Pt NPs., (© 2022 Wiley-VCH GmbH.)

The optimization of MgO-based adsorbents as advanced CO 2 -capture materials is predominantly focused on their molten-salt modification, for which theoretical and experimental contributions provide great insights for their high CO 2 -capture performance. The underlying mechanism of the promotion effect of the molten salt on CO 2 capture, however, is a topic of controversy. Herein, advanced experimental characterization techniques, including in situ environmental transmission electron microscopy (eTEM) and CO 2 chemisorption by diffuse-reflectance infrared Fourier transform spectroscopy (DRIFTS), transient 18 O-isotopic exchange, and density functional theory (DFT), are employed to elucidate the mechanism of the CO 2 interaction with molten-salt-modified MgO in the 250-400 °C range. Herein, eTEM studies using low (2-3 mbar) and high (700 mbar) CO 2 pressures illustrate the dynamic evolution of the molten NaNO 3 salt promoted and unpromoted MgO carbonation with high magnification (<50 nm). The formation of 18 O-NaNO 3 (use of 18 O 2 ) and C 16 O 18 O following CO 2 interaction, verifies the proposed reaction path: conversion of NO 3 - (NO 3 -  → NO 2 +  + O 2- ), adsorption of NO 2 + on MgO with significant weakening of CO 2 adsorption strength, and formation of [Mg 2+ … O 2- ] ion pairs preventing the development of an impermeable MgCO 3 shell, which largely increases the rate of bulk MgO carbonation., (© 2021 Wiley-VCH GmbH.)

The shuttling of soluble lithium polysulfides between the electrodes leads to serious capacity fading and excess use of electrolyte, which severely bottlenecks practical use of Li-S batteries. Here, selective catalysis is proposed as a fundamental remedy for the consecutive solid-liquid-solid sulfur redox reactions. The proof-of-concept Indium (In)-based catalyst targetedly decelerates the solid-liquid conversion, dissolution of elemental sulfur to polysulfides, while accelerates the liquid-solid conversion, deposition of polysulfides into insoluble Li 2 S, which basically reduces accumulation of polysulfides in electrolyte, finally inhibiting the shuttle effect. The selective catalysis is revealed, experimentally and theoretically, by changes of activation energies and kinetic currents, modified reaction pathway together with the probed dynamically changing catalyst (LiInS 2 catalyst), and gradual deactivation of the In-based catalyst. The In-based battery works steadily over 1000 cycles at 4.0 C and yields an initial areal capacity up to 9.4 mAh cm -2 with a sulfur loading of ≈9.0 mg cm -2 ., (© 2021 Wiley-VCH GmbH.)

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 H 2 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 V RHE with high stability. The post-reaction structure analysis reveals the Ni nanosheets would transfer electrons to carbon and readily turn into NiO x 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., (© 2021 Wiley-VCH GmbH.)

The recent mechanistic understanding of active sites, adsorbed intermediate products, and rate-determining steps (RDS) of nitrogen (N)-modified carbon catalysts in electrocatalytic oxygen reduction (ORR) and oxygen evolution reaction (OER) are still rife with controversy because of the inevitable coexistence of diverse N configurations and the technical limitations for the observation of formed intermediates. Herein, seven kinds of aromatic molecules with designated single N species are used as model structures to investigate the explicit role of each common N group in both ORR and OER. Specifically, dynamic evolution of active sites and key adsorbed intermediate products including O 2 (ads), superoxide anion O 2 - *, and OOH* are monitored with in situ spectroscopy. We propose that the formation of *OOH species from O 2 - * (O 2 - *+H 2 O→OOH*+OH - ) is a possible RDS during the ORR process, whereas the generation of O 2 from OOH* species is the most likely RDS during the OER process., (© 2020 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Metallic platinum nanocatalysts play a key role in the liquid-phase selective hydrogenation of substrates with more than one unsaturated bond. However, the commonly applied explanation for the effects of different electronic and geometric properties of catalysts on reactions remains of a heuristic nature due to the difficulties involved in preparing catalysts with precise structure. In this work, we have directly loaded pre-synthesized metallic platinum nanoparticles onto well-structured ZnO nanorods and then subjected them to thermal treatment in a reductive atmosphere for different temperatures. The effects of the different electronic and geometric properties of the catalysts on the selective reduction of 3-nitrostyrene to 3-vinylaniline as a model reaction have been rigorously explored through an analysis of the catalyst structures and the activity and selectivity profiles. Both the electron transfer from zinc to platinum and the decreased platinum surface density as a result of the formation of PtZn intermetallic compounds are key factors for improving the selectivity for the desired 3-vinylaniline. Azobenzene was detected in the reaction with all the Pt/ZnO catalysts after 10-90 min, which indicates that the reaction follows a condensation mechanism., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Graphene oxides (GOs) are popular catalyst supports for precious metals in nanoparticle form. The hydrogen oxidation reaction (HOR) and the hydrogen evolution reaction (HER) on individual GO platelets decorated with Pd nanoparticles (Pd/GOs) were investigated. The results suggest that the catalytic activity is confined to the zone physically close to the point of electrical contact between platelet and electrode with just a fraction of the platelet active., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Controllable synthesis of well-defined supported intermetallic catalysts is desirable because of their unique properties in physical chemistry. To accurately pinpoint the evolution of such materials at an atomic-scale, especially clarification of the initial state under a particular chemical environment, will facilitate rational design and optimal synthesis of such catalysts. The dynamic formation of a ZnO-supported PdZn catalyst is presented, whereby detailed analyses of in situ transmission electron microscopy, electron energy-loss spectroscopy, and in situ X-ray diffraction are combined to form a nanoscale understanding of PdZn phase transitions under realistic catalytic conditions. Remarkably, introduction of atoms (H and Zn in sequence) into the Pd matrix was initially observed. The resultant PdH x is an intermediate phase in the intermetallic formation process. The evolution of PdH x in the PdZn catalyst initializes at the PdH x /ZnO interfaces, and proceeds along the PdH x ⟨111⟩ direction., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The emergence of van der Waals (vdW) heterostructures of 2D materials has opened new avenues for fundamental scientific research and technological applications. However, the current concepts and strategies of material engineering lack feasibilities to comprehensively regulate the as-obtained extrinsic physicochemical characters together with intrinsic properties and activities for optimal performances. A 3D mesoporous vdW heterostructure of graphene and nitrogen-doped MoS 2 via a two-step sequential chemical vapor deposition method is constructed. Such strategy is demonstrated to offer an all-round engineering of 2D materials including the morphology, edge, defect, interface, and electronic structure, thereby leading to robustly modified properties and greatly enhanced electrochemical activities. The hydrogen evolution is substantially accelerated on MoS 2 , while the oxygen reduction and evolution are significantly improved on graphene. This work provides a powerful overall engineering strategy of 2D materials for electrocatalysis, which is also enlightening for other nanomaterials and energy-related applications., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The preparation of photocatalysts with high activities under visible-light illumination is challenging. We report the rational design and construction of a zirconium-doped anatase catalyst (S-Zr-TiO 2 ) with Brønsted acidity and photoactivity as an efficient catalyst for the degradation of phenol under visible light. Electron microscopy images demonstrate that the zirconium sites are uniformly distributed on the sub-10 nm anatase crystals. UV-visible spectrometry indicates that the S-Zr-TiO 2 is a visible-light-responsive catalyst with narrower band gap than conventional anatase. Pyridine-adsorption infrared and acetone-adsorption 13 C NMR spectra confirm the presence of Brønsted acidic sites on the S-Zr-TiO 2 sample. Interestingly, the S-Zr-TiO 2 catalyst exhibits high catalytic activity in the degradation of phenol under visible-light illumination, owing to a synergistic effect of the Brønsted acidity and photoactivity. Importantly, the S-Zr-TiO 2 shows good recyclability., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A bifunctional graphene catalyst with abundant topological defects is achieved via the carbonization of natural gelatinized sticky rice to probe the underlying oxygen electrocatalytic mechanism. A nitrogen-free configuration with adjacent pentagon and heptagon carbon rings is revealed to exhibit the lowest overpotential for both oxygen reduction and evolution catalysis. The versatile synthetic strategy and novel insights on the activity origin facilitate the development of advanced metal-free carbocatalysts for a wide range of electrocatalytic applications., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Carbon nanotubes (CNTs) are functionalized with nitrogen atoms for reduction of carbon dioxide (CO2 ). The investigation explores the origin of the catalyst's activity and the role of nitrogen chemical states therein. The catalysts show excellent performances, with about 90 % current efficiency for CO formation and stability over 60 hours. The Tafel analyses and density functional theory calculations suggest that the reduction of CO2 proceeds through an initial rate-determining transfer of one electron to CO2 , which leads to the formation of carbon dioxide radical anion (CO2 (.-) ). The initial reduction barrier is too high on pristine CNTs, resulting in a very high overpotentials at which the hydrogen evolution reaction dominates over CO2 reduction. The doped nitrogen atoms stabilize the radical anion, thereby lowering the initial reduction barrier and improving the intrinsic activity. The most efficient nitrogen chemical state for this reaction is quaternary nitrogen, followed by pyridinic and pyrrolic nitrogen., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

P-type Cu2 O has been long considered as an attractive photocatalyst for photocatalytic water reduction, but few successful examples has been reported. Here, we report the synthesis of TiO2 (core)/Cu2 O (ultrathin film shell) nanorods by a redox reaction between Cu(2+) and in-situ generated Ti(3+) when Cu(2+) -exchanged H-titanate nanotubes are calcined in air. Owing to the strong TiO2 -Cu2 O interfacial interaction, TiO2 (core)/Cu2 O (ultrathin film shell) nanorods are highly active and stable in photocatalytic water reduction. The TiO2 core and Cu2 O ultrathin film shell respectively act as the photosensitizer and cocatalyst, and both the photoexcited electrons in the conduction band and the holes in the valence band of TiO2 respectively transfer to the conduction band and valence band of the Cu2 O ultrathin film shell. Our results unambiguously show that Cu2 O itself can act as the highly active and stable cocatalyst for photocatalytic water reduction., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The lithium-oxygen (Li-O2 ) battery is a very appealing candidate for advanced high energy applications owing to its exceptionally high specific energy. However, its poor energy efficiency, rate capability, and cyclability remain key barriers to its practical application. In this work, using a rationally designed cathode based on a bimodal mesoporous nitrogen-doped graphene/carbon nanotube (NGC) composite, we have developed a Li-O2 battery demonstrating enhanced round-trip efficiency (ca. 85 %) and excellent cyclability over 400 cycles under a high current rate of 500 mA g(-1) . The excellent cyclability and rate capability are attributed to improved stability of the aggressive LiO2 intermediate on the nitrogen-doped carbon surface in addition to the favorable hierarchical architecture of NGC. These results demonstrate a valuable research direction to achieve highly stable and reversible Li-O2 batteries through tuning the surface chemistry of the cathode in addition to finding a stable electrolyte solvent., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In alkaline medium, it seems that both metal-free and iron-containing carbon-based catalysts, such as nitrogen-doped nanocarbon materials, FeOx -doped carbon, and Fe/N/C catalysts, are active for the oxygen reduction reaction (ORR). However, the order of activity of these different active compositions has not been clearly determined. Herein, we synthesized nitrogen-doped carbon black (NCB), Fe3 O4 /CB, Fe3 O4 /NCB, and FeN4 /CB. Through the systematic study of the ORR catalytic activity of these four catalysts in alkaline solution, we confirmed the difference in the catalytic activity and catalytic mechanism for nitrogen, iron oxides, and Fe-N complexes, respectively. In metal-free NCB, nitrogen can improve the ORR catalytic activity with a four-electron pathway. Fe3 O4 /CB catalyst did not exhibit improved activity over that of NCB owing to the poor conductivity and spinel structure of Fe3 O4 . However, FeN4 coordination compounds as the active sites showed excellent ORR catalytic activity., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Non-precious metal oxide/carbon hybrid electrocatalysts are of increasing importance for the oxygen reduction reaction (ORR). A synergistic effect is commonly used to explain the superior ORR activity exerted by metal oxide/nanocarbon hybrids, and this effect is attributed to covalently coupled interfaces between the two materials. However, the origin of the high activity, the structure, and the electrocatalytic nature of the interface remain unclear. By combining X-ray photoelectron spectroscopy with synchrotron far-infrared spectroscopy, we resolved the interface structure between spinel manganese oxide nanocrystals and graphene oxide nanoribbons, and the role of this interface in the promoted ORR. Moreover, we demonstrated the excellent ORR activity by a functional synergism of the hybrid constituents through a series of comparative electrochemical experiments., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Two kinds of phosphorus-modified onion-like carbons dominated by C-O-P bonds and C-P bonds were fabricated and further used as catalysts in the oxygen reduction reaction (ORR). The results show that the bonding state of phosphorus has a significant effect on the ORR catalytic activity. The formation of C-O-P bonds improves ORR activity, whereas C-P bonds play an adverse role in stabilizing the key intermediates during the ORR owing to the distorted graphitic structure, as confirmed by the work function value., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

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 Fe3 C 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, [Fe(III)(porphyrin)(pyridine)2]). We expect the understanding of the FeN6 structure will pave the way towards new advanced Fe-N based electrocatalysts., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A composite catalyst including palladium nanoparticles on titania (TiO2) and on nitrogen-modified porous carbon (Pd/TiO2@N-C) is synthesized from palladium salts, tetrabutyl titanate, and chitosan. N2 sorption isotherms show that the catalyst has a high BET surface area (229 m(2)  g(-1)) and large porosity. XPS and TEM characterization of the catalyst shows that palladium species with different chemical states are well dispersed across the TiO2 and nitrogen-modified porous carbon, respectively. The Pd/TiO2@N-C catalyst is very active and shows excellent stability towards hydrogenation of vanillin to 2-methoxy-4-methylphenol using formic acid as hydrogen source. This activity can be attributed to a synergistic effect between the Pd/TiO2 (a catalyst for dehydrogenation of formic acid) and Pd/N-C (a catalyst for hydrogenation of vanillin) sites., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Hybrid nanocarbon, comprised of a diamond core and a graphitic shell with a variable sp(2)-/sp(3)-carbon ratio, is controllably obtained through sequential annealing treatment (550-1300 °C) of nanodiamond. The formation of sp(2) carbon increases with annealing temperature and the nanodiamond surface is reconstructed from amorphous into a well-ordered, onion-like carbon structure via an intermediate composite structure--a diamond core covered by a defective, curved graphene outer shell. Direct dehydrogenation of propane shows that the sp(2)-/sp(3)-nanocomposite exhibits superior catalytic performance to that of individual nanodiamond and graphitic nanocarbon. The optimum catalytic activity of the diamond/graphene composite depends on the maximum structural defectiveness and high chemical reactivity of the ketone groups. Ketone-type functional groups anchored on the defects/vacancies are active for propene formation; nevertheless, once the oxygen functional groups are desorbed, the defects/vacancies alone might be active sites responsible for the C-H bond activation of propane., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A promising energy storage material, MnO2 /hierarchically porous carbon (HPC) nanocomposites, with exceptional electrochemical performance and ultrahigh energy density was developed for asymmetric supercapacitor applications. The microstructures of MnO2 /HPC nanocomposites were characterized by transmission electron microscopy, scanning transmission electron microscopy, and electron dispersive X-ray elemental mapping analysis. The 3-5 nm MnO2 nanocrystals at mass loadings of 7.3-10.8 wt % are homogeneously distributed onto the HPCs, and the utilization efficiency of MnO2 on specific capacitance can be enhanced to 94-96 %. By combining the ultrahigh utilization efficiency of MnO2 and the conductive and ion-transport advantages of HPCs, MnO2 /HPC electrodes can achieve higher specific capacitance values (196 F g(-1) ) than those of pure carbon electrodes (60.8 F g(-1) ), and maintain their superior rate capability in neutral electrolyte solutions. The asymmetric supercapacitor consisting of a MnO2 /HPC cathode and a HPC anode shows an excellent performance with energy and power densities of 15.3 Wh kg(-1) and 19.8 kW kg(-1) , respectively, at a cell voltage of 2 V. Results obtained herein demonstrate the excellence of MnO2 /HPC nanocomposites as energy storage material and open an avenue to fabricate the next generation supercapacitors with both high power and energy densities., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Carbon is a unique and versatile element that is capable of forming different architectures at nanoscale. The element has become a key component in nanoscience and nanotechnology. Transmission electron microscopy (TEM) acts as "our eyes" enabling us not only to reveal the morphology, but also to provide structural, chemical and electronic information of nanocarbon on the atomic level. In fact, except for fullerene, nearly all types of carbon nanomaterials were discovered by TEM, such as carbon nanotubes, carbon nanocones, and graphene-like nanocarbon. It cannot be imagined what nanoscience and nanotechnology would be without the contributions of TEM. Herein, the "interaction" between TEM and the science of carbon nanomaterials is reviewed and it is demonstrated for some selected examples that TEM provides a dramatic driving force for the development of nanocarbon science., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Same selectivity hides different pathways: The same apparent 4-electron process for the oxygen-reduction-reaction hides different pathways over carbon-supported cobalt oxide catalysts depending on the potential. At low overpotentials, the ORR intermediate HO(2) (-) preferably disproportionates to oxygen, whereas at high overpotentials the disproportionation and reduction reaction occur in parallel., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Palladium dynamics: Under hydrogenation conditions, saturating over-active palladium by carbon diffusion leads to a stable and selective particle surface. By choosing supports with suitable geometric structures and establishing a strong interaction between supports and metal particles, accumulated species can be regularly rearranged and reaction-selective phases can be exposed (see figure)., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A family of photocatalysts for water splitting into hydrogen was prepared by distributing TiO(6) units in an MTi-layered double hydroxide matrix (M = Ni, Zn, Mg) that displays largely enhanced photocatalytic activity with an H(2)-production rate of 31.4 μmol  h(-1) as well as excellent recyclable performance. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) mapping and XPS measurement reveal that a high dispersion of TiO(6) octahedra in the layered doubled hydroxide (LDH) matrix was obtained by the formation of an M(2+)-O-Ti network, rather different from the aggregation state of TiO(6) in the inorganic layered material K(2)Ti(4)O(9). Both transient absorption and photoluminescence spectra demonstrate that the electron-hole recombination process was significantly depressed in the Ti-containing LDH materials relative to bulk Ti oxide, which is attributed to the abundant surface defects that serve as trapping sites for photogenerated electrons verified by positron annihilation and extended X-ray absorption fine structure (EXAFS) techniques. In addition, a theoretical study on the basis of DFT calculations demonstrates that the electronic structure of the TiO(6) units was modified by the adjacent MO(6) octahedron by means of covalent interactions, with a much decreased bandgap of 2.1 eV, which accounts for its superior water-splitting behavior. Therefore, the dispersion strategy for TiO(6) units within a 2D inorganic matrix can be extended to fabricate other oxide or hydroxide catalysts with greatly enhanced performance in photocatalysis and energy conversion., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)