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Electrochemical acetylene reduction (EAR) employing Cu catalysts represents an environmentally friendly and cost-effective method for ethylene production and purification. However, Cu-based catalysts encounter product selectivity issues stemming from carbon-carbon coupling and other side reactions. We explored the use of secondary metals to modify Cu-based catalysts and identified Cd decoration as particular effective. Cd decoration demonstrated a high ethylene Faradaic efficiency (FE) of 98.38 % with well-inhibited carbon-carbon coupling reactions (0.06 % for butadiene FE at -0.5 V versus reversible hydrogen electrode) in a 5 vol % acetylene gas feed. Notably, ethylene selectivity of 99.99 % was achieved in the crude ethylene feed during prolonged stability tests. Theoretical calculations revealed that Cd metal accelerates the water dissociation on neighboring Cu surfaces allowing more H* to participate in the acetylene semi-hydrogenation, while increasing the energy barrier for carbon-carbon coupling, thereby contributing to a high ethylene semi-hydrogenation efficiency and significant inhibition of carbon-carbon coupling. This study provides a paradigm for a deeper understanding of secondary metals in regulating the product selectivity of EAR electrocatalysts., (© 2024 Wiley‐VCH GmbH.)

The construction of platinum (Pt) atomic layers is an effective strategy to improve the utilization efficiency of Pt atoms in electrocatalysis, thus is important for reducing the capital costs of a wide range of energy storage and conversion devices. However, the substrates used to grow Pt atomic layers are largely limited to noble metals and their alloys, which is not conducive to reducing catalyst costs. Herein, low-cost chromium nitride (CrN) is utilized as a support for the loading of epitaxial ultrathin Pt atomic layers via a simple thermal ammonolysis method. Owing to the strong anchoring and electronic regulation of Pt atomic layers by CrN, the obtained Pt atomic layers catalyst (containing electron-deficient Pt sites) exhibits excellent activity and endurance for the formic acid oxidation reaction, with a mass activity of 5.17 A mg Pt -1 that is 13.6 times higher than that of commercial Pt/C catalyst. This novel strategy demonstrates that CrN can replace noble metals as a low-cost substrate for constructing Pt atomic layers catalysts., (© 2023 Wiley-VCH GmbH.)

Electrochemical acetylene reduction (EAR) is a promising strategy for removing acetylene from ethylene-rich gas streams. However, suppressing the undesirable hydrogen evolution is vital for practical applications in acetylene-insufficient conditions. Herein, Cu single atoms are immobilized on anatase TiO 2 nanoplates (Cu-SA/TiO 2 ) for electrochemical acetylene reduction, achieving an ethylene selectivity of ≈97% with a 5 vol% acetylene gas feed (Ar balance). At the optimal Cu-single-atom loading, Cu-SA/TiO 2 is able to effectively suppress HER and ethylene over-hydrogenation even when using dilute acetylene (0.5 vol%) or ethylene-rich gas feeds, delivering a 99.8% acetylene conversion, providing a turnover frequency of 8.9 × 10 -2  s -1 , which is superior to other EAR catalysts reported to date. Theoretical calculations show that the Cu single atoms and the TiO 2 support acted cooperatively to promote charge transfer to adsorbed acetylene molecules, whilst also inhibiting hydrogen generation in alkali environments, thus allowing selective ethylene production with negligible hydrogen evolution at low acetylene concentrations., (© 2023 Wiley-VCH GmbH.)

The large-scale application of proton exchange membrane fuel cells is currently hampered by high cost of commercial Pt catalysts and their susceptibility to poisoning by CO impurities in H 2 feed. In this context, the development of CO-tolerant electrocatalysts with high Pt atom utilization efficiency for hydrogen oxidation reaction (HOR) is of critical importance. Herein, Pt single atoms are successfully immobilized on chromium nitride nanoparticles by atomic layer deposition method, denoted as Pt SACs/CrN. Electrochemical tests establish Pt SACs/CrN to be a very efficient HOR catalyst, with a mass activity that is 5.7 times higher than commercial PtRu/C. Strikingly, the excellent performance of Pt SACs/CrN is maintained after introducing 1000 ppm of CO in H 2 feed. The excellent CO-tolerance of Pt SACs/CrN is related to weaker CO adsorption on Pt single atoms. This work provides guidelines for the design and construction of active and CO-tolerant catalysts for HOR., (© 2022 Wiley-VCH GmbH.)

Fe-N-C catalysts offer excellent performance for the oxygen reduction reaction (ORR) in alkaline media. With a view toward boosting the intrinsic ORR activity of Fe single-atom sites in Fe-N-C catalysts, fine-tuning the local coordination of the Fe sites to optimize the binding energies of ORR intermediates is imperative. Herein, a porous FeN 4 -O-NCR electrocatalyst rich in catalytically accessible FeN 4 -O sites (wherein the Fe single atoms are coordinated to four in-plane nitrogen atoms and one subsurface axial oxygen atom) supported on N-doped carbon nanorods (NCR) is reported. Fe K-edge X-ray absorption spectroscopy (XAS) verifies the presence of FeN 4 -O active sites in FeN 4 -O-NCR, while density functional theory calculations reveal that the FeN 4 -O coordination offers a lower energy and more selective 4-electron/4-proton ORR pathway compared to traditional FeN 4 sites. Electrochemical tests validate the outstanding intrinsic activity of FeN 4 -O-NCR for alkaline ORR, outperforming Pt/C and almost all other M-N-C catalysts reported to date. A primary zinc-air battery constructed using FeN 4 -O-NCR delivers a peak power density of 214.2 mW cm -2 at a current density of 334.1 mA cm -2 , highlighting the benefits of optimizing the local coordination of iron single atoms., (© 2022 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

Developing efficient and stable Pt-based oxygen reduction reaction (ORR) catalysts is a way to promote the large-scale application of fuel cells. Pt-based alloy nanowires are promising ORR catalysts, but their application is hampered by activity loss caused by structural destruction during long-term cycling. Herein, the preparation of ordered PtFeIr intermetallic nanowire catalysts with an average diameter of 2.6 nm and face-centered tetragonal structure (fct-PtFeIr/C) is reported. A silica-protected strategy prevents the deformation of PtFeIr nanowires during the phase transition at high temperature. The as-prepared fct-PtFeIr/C exhibited superior mass activity for ORR (2.03 A mg Pt -1 ) than disordered PtFeIr nanowires with face-centered cubic structure (1.11 A mg Pt -1 ) and commercial Pt/C (0.21 A mg Pt -1 ). Importantly, the structure and electrochemical performance of fct-PtFeIr/C were maintained after stability tests, showing the advantages of the ordered structure., (© 2021 Wiley-VCH GmbH.)

Single atom catalysts (SACs) have received a great deal of attention due to their extremely high active site utilization and superior activities. The exploration of metal SACs has been carried out by screening the elemental periodic table from first-row to second-row, and even third-row transition metals. However, Re SACs have not been reported, even if Re metal sites also play essential roles in catalyzing many important reactions. The construction of Re SACs may maximize Re catalytic sites and provide new Re active sites for higher activity. Herein, we used 1,10-phenanthroline to complex Re cations on carbon black, followed by heat treatment to obtain Re SAC. The Re SAC exhibited an oxygen reduction reaction (ORR) half-wave potential of 0.72 V versus reversible hydrogen electrode (RHE) in 0.1 M KOH, superior to Re nanoparticles catalyst (0.67 V vs. RHE). Re SAC exhibited better stability at 0.5 V vs. RHE than Pt/C, showing potential as a new electrocatalyst for ORR., (© 2021 Wiley-VCH GmbH.)

NiFe-layered double hydroxides (NiFe-LDH) are among the most active catalysts developed to date for the oxygen evolution reaction (OER) in alkaline media, though their long-term OER stability remains unsatisfactory. Herein, we reveal that the stability degradation of NiFe-LDH catalysts during alkaline OER results from a decreased number of active sites and undesirable phase segregation to form NiOOH and FeOOH, with metal dissolution underpinning both of these deactivation mechanisms. Further, we demonstrate that the introduction of cation-vacancies in the basal plane of NiFe LDH is an effective approach for achieving both high catalyst activity and stability during OER. The strengthened binding energy between the metals and oxygen in the LDH sheets, together with reduced lattice distortions, both realized by the rational introduction of cation vacancies, drastically mitigate metal dissolution from NiFe-LDH under high oxidation potentials, resulting in the improved long-term OER stability. In addition, the cation vacancies (especially M 3+ vacancies) accelerate the evolution of surface γ-(NiFe)OOH phases, thereby boosting the OER activity. The present study highlights that tailoring atomic cation-vacancies is an important strategy for the development of active and stable OER electrocatalysts., (© 2021 Wiley-VCH GmbH.)

Fe single-atom catalysts (Fe SACs) with atomic FeN x active sites are very promising alternatives to platinum-based catalysts for the oxygen reduction reaction (ORR). The pyrolysis of metal-organic frameworks (MOFs) is a common approach for preparing Fe SACs, though most MOF-derived catalysts reported to date are microporous and thus suffer from poor mass transfer and a high proportion of catalytically inaccessible FeN x active sites. Herein, NH 2 -MIL-101(Al), a MOF possessing a mesoporous cage architecture, is used as the precursor to prepare a series of N-doped carbon supports (denoted herein as NC-MIL101-T) with a well-defined mesoporous structure at different pyrolysis temperatures. The NC-MIL101-T supports are then impregnated with a Fe(II)-phenanthroline complex, and heated again to yield Fe SAC-MIL101-T catalysts rich in accessible FeN x single atom sites. The best performing Fe SAC-MIL101-1000 catalyst offers outstanding ORR activity in alkaline media, evidenced by an ORR half-wave potential of 0.94 V (vs RHE) in 0.1 m KOH, as well as excellent performance in both aqueous primary zinc-air batteries (a near maximum theoretical energy density of 984.2 Wh kg Zn -1 ) and solid-state zinc-air batteries (a peak power density of 50.6 mW cm -2 and a specific capacity of 724.0 mAh kg Zn -1 )., (© 2021 Wiley-VCH GmbH.)

Carbon-supported Ni II single-atom catalysts with a tetradentate Ni-N 2 O 2 coordination formed by a Schiff base ligand-mediated pyrolysis strategy are presented. A Ni II complex of the Schiff base ligand (R,R)-(-)-N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine was adsorbed onto a carbon black support, followed by pyrolysis of the modified carbon material at 300 °C in Ar. The Ni-N 2 O 2 /C catalyst showed excellent performance for the electrocatalytic reduction of O 2 to H 2 O 2 through a two-electron transfer process in alkaline conditions, with a H 2 O 2 selectivity of 96 %. At a current density of 70 mA cm -2 , a H 2 O 2 production rate of 5.9 mol g cat. -1  h -1 was achieved using a three-phase flow cell, with good catalyst stability maintained over 8 h of testing. The Ni-N 2 O 2 /C catalyst could electrocatalytically reduce O 2 in air to H 2 O 2 at a high current density, still affording a high H 2 O 2 selectivity (>90 %). A precise Ni-N 2 O 2 coordination was key to the performance., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The development of efficient and stable electrocatalysts for the oxygen reduction reaction (ORR) is critical for the large-scale production of fuel cells. Platinum (Pt) nanoparticle catalysts show excellent performance for ORR, though the high cost of Pt is a limiting factor that directly impacts fuel cell production costs. Alloying Pt with other transition metals is an effective strategy to reduce Pt utilization whilst maintaining good ORR performance. In this work, novel hollow PtFe alloy catalysts were successfully synthesized by high-temperature pyrolysis of SiO 2 -coated Pt-Fe 3 O 4 nanoparticle dimers supported on carbon at 900 °C, followed by SiO 2 shell removal and partial dealloying of the PtFe nanoparticles formed using HF. The obtained hollow PtFe nanoparticle catalysts (denoted herein as PtFe-900) showed a 2.3-fold enhancement in ORR mass activity compared to PtFe nanoparticles synthesized without SiO 2 protection, and a remarkable 7.8-fold enhancement relative to a commercial Pt/C catalyst. Further, after 10 000 potential cycles, the ORR mass activity of PtFe-900 remained very high (90.9 % of the initial mass activity). The outstanding ORR performance of PtFe-900 can be attributed to the modification of Pt lattice and electronic structure by alloying with Fe at high temperature under the protection of the SiO 2 coating. This work guides the development of improved, highly dispersed Pt-based alloy nanoparticle catalysts for ORR and fuel cell applications., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A challenging but pressing task to design and synthesize novel, efficient, and robust pH-universal hydrogen evolution reaction (HER) electrocatalysts for scalable and sustainable hydrogen production through electrochemical water splitting. Herein, we report a facile method to prepare an efficient and robust Ru-M (M=Ni, Mn, Cu) bimetal nanoparticle and carbon quantum dot hybrid (RuM/CQDs) for pH-universal HER. The RuNi/CQDs catalysts exhibit outstanding HER performance at all pH levels. The unexpected low overpotentials of 13, 58, and 18 mV shown by RuNi/CQDs allow a current density of 10 mA cm -2 in 1 m KOH, 0.5 m H 2 SO 4 , and 1 m PBS, respectively, for Ru loading at 5.93 μgRu cm -2 . This performance is among the best catalytic activities reported for any platinum-free electrocatalyst. Theoretical studies reveal that Ni doping results in a moderate weakening of the hydrogen bonding energy of nearby surface Ru atoms, which plays a critical role in improving the HER activity., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Nanozymes have attracted extensive interest owing to their high stability, low cost and easy preparation, especially in the field of cancer therapy. However, the relatively low catalytic activity of nanozymes in the tumor microenvironment (TME) has limited their applications. Herein, we report a novel nanozyme (PtFe@Fe 3 O 4 ) with dual enzyme-like activities for highly efficient tumor catalytic therapy. PtFe@Fe 3 O 4 shows the intrinsic photothermal effect as well as photo-enhanced peroxidase-like and catalase-like activities in the acidic TME, thereby effectively killing tumor cells and overcoming the tumor hypoxia. Importantly, a possible photo-enhanced synergistic catalytic mechanism of PtFe@Fe 3 O 4 was first disclosed. We believe that this work will advance the development of nanozymes in tumor catalytic therapy., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Heteroatom-doped carbon catalysts are currently attracting enormous attention due to their excellent performance for the electrocatalytic carbon dioxide reduction reaction (ECRR). However, the origin of the high catalytic activities of doped-carbon materials remains obscure with the role of intrinsic carbon defects in promoting the ECRR receiving little attention despite the abundance of carbon defects in all carbon-based catalytic materials. Herein, a positive correlation is reported between the ECRR performance of carbon-based catalysts and the content of intrinsic carbon defects contained within these catalysts. Further, it is demonstrated that defective porous carbon catalysts containing no active heteroatom dopants also show excellent catalytic performance for ECRR. C K-edge near edge X-ray absorption fine structure measurements and density functional theory calculations reveal that sp 2 defects (octagonal and pentagonal) rather than edge defects are key to the excellent ECRR activity of the defective porous carbon catalysts. This work thus makes an important contribution to the understanding of the origin of the ECRR activity of carbon-based catalysts, with heteroatom doping perhaps being less important than previously envisaged for achieving a high ECRR performance., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The selective hydrogenation of acetylene to ethylene in an ethylene-rich gas stream is an important process in the chemical industry. Pd-based catalysts are widely used in this reaction due to their excellent hydrogenation activity, though their selectivity for acetylene hydrogenation and durability need improvement. Herein, the successful synthesis of atomically dispersed Pd single-atom catalysts on nitrogen-doped graphene (Pd 1 /N-graphene) by a freeze-drying-assisted method is reported. The Pd 1 /N-graphene catalyst exhibits outstanding activity and selectivity for the hydrogenation of C 2 H 2 with H 2 in the presence of excess C 2 H 4 under photothermal heating (UV and visible-light irradiation from a Xe lamp), achieving 99% conversion of acetylene and 93.5% selectivity to ethylene at 125 °C. This remarkable catalytic performance is attributed to the high concentration of Pd active sites on the catalyst surface and the weak adsorption energy of ethylene on isolated Pd atoms, which prevents C 2 H 4 hydrogenation. Importantly, the Pd 1 /N-graphene catalyst exhibits excellent durability at the optimal reaction temperature of 125 °C, which is explained by the strong local coordination of Pd atoms by nitrogen atoms, which suppresses the Pd aggregation. The results presented here encourage the wider pursuit of solar-driven photothermal catalyst systems based on single-atom active sites for selective hydrogenation reactions., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A series of novel CoFe-based catalysts are successfully fabricated by hydrogen reduction of CoFeAl layered-double-hydroxide (LDH) nanosheets at 300-700 °C. The chemical composition and morphology of the reaction products (denoted herein as CoFe-x) are highly dependent on the reduction temperature (x). CO 2 hydrogenation experiments are conducted on the CoFe-x catalysts under UV-vis excitation. With increasing LDH-nanosheet reduction temperature, the CoFe-x catalysts show a progressive selectivity shift from CO to CH 4 , and eventually to high-value hydrocarbons (C 2+ ). CoFe-650 shows remarkable selectivity toward hydrocarbons (60% CH 4 , 35% C 2+ ). X-ray absorption fine structure, high-resolution transmission electron microscopy, Mössbauer spectroscopy, and density functional theory calculations demonstrate that alumina-supported CoFe-alloy nanoparticles are responsible for the high selectivity of CoFe-650 for C 2+ hydrocarbons, also allowing exploitation of photothermal effects. This study demonstrates a vibrant new catalyst platform for harnessing clean, abundant solar-energy to produce valuable chemicals and fuels from CO 2 ., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Carbon quantum dots (CQDs) have attracted widespread interest for photocatalytic applications, owing to their low cost and excellent electron donor/acceptor properties. However, their advancement as visible-light photosensitizers in CQDs/semiconductor nanocomposites is currently impaired by their poor quantum yields (QYs). Herein, we describe the successful fabrication of a series of nitrogen-doped CQDs (NCDs) with N/C atomic ratios ranging from 0.14-0.30. NCDs with the highest N-doping level afforded a remarkable external QY of 66.8 % at 360 nm, and outstanding electron transfer properties and photosensitization efficiencies when physically adsorbed on P25 TiO 2 . A NCDs/P25-TiO 2 hybrid demonstrated excellent performance for hydrogen evolution in aqueous methanol under both UV and visible-light illumination relative to pristine P25 TiO 2 . Controlled nitrogen doping of CQDs therefore represents a very effective strategy for optimizing the performance of CQDs/semiconductor hybrid photocatalysts., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A facile and green process was developed for the synthesis of pyrochlore H 4 Nb 2 O 7 hollow microspheres by using hydrothermal treatment of Sn 2 Nb 2 O 7 hollow microspheres in aqueous 2 m HCl at 100-180 °C. The facile transformation of Sn 2 Nb 2 O 7 into H 4 Nb 2 O 7 is facilitated by the intrinsic ion-exchange capability of Sn 2 Nb 2 O 7 . The resulting H 4 Nb 2 O 7 hollow microspheres (diameter 1-2 μm, shell thickness 100-200 nm) displayed excellent photocatalytic performance for overall water splitting under UV irradiation, affording H 2 and O 2 evolution rates of 240 and 116 μmol h -1  g -1 , respectively. Following decoration with 0.5 wt % Pt, the H 4 Nb 2 O 7 hollow microspheres demonstrated remarkably high H 2 and O 2 evolution rates of 1240 and 600 μmol h -1  g -1 , respectively. To our knowledge, this work is the first reported study examining the photocatalytic performance of H 4 Nb 2 O 7 for water splitting. The hydrothermal synthesis method described here is also applicable to the synthesis of pyrochlore H 4 Ta 2 O 7 from Sn 2 Ta 2 O 7 , highlighting the versatility of the approach., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Photoinduced syntheses offer significant advantages over conventional thermal strategies, including improved control over reaction kinetics and low synthesis temperatures, affording nanoparticles with nontrivial and thermodynamically unstable structures. However, the photoinduced syntheses of non-metallic nanocrystalline products (such as metal sulfides) have not yet been reported. Herein, we demonstrate the first photoinduced synthesis of ultrafine (sub-2 nm) Ag 2 S quantum dots (QDs) from Ag nanoparticles at 10 °C. By thorough investigation of the mechanism for the transformation, a fundamental link was established between the intrinsic structures of the molecular intermediates and the final Ag 2 S products. Our results confirm the viability of low-temperature photochemical approaches in metal sulfide synthesis, and demonstrate a new rule which could be followed in it., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Mesoporous carbon nanospheres containing porphyrin-like metal centers (denoted as "PMCS") are successfully synthesized by the pyrolysis of an imidazolate framework using a mesoporous-silica protection strategy. The PMCS allow infrared and photoacoustic imaging and synergetic photothermal therapy/photodynamic therapy derived from the porphyrin-like moieties, offering the possibility of real-time monitoring of therapeutic processes and image-guided precise conformal phototherapy. PMCS thus represent a novel multifunctional theranostic platform for improved treatment efficiencies., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A simple seaweed biomass conversion strategy is proposed to synthesize highly porous multishelled Ni-rich Li(Ni x Co y Mn z )O 2 hollow fibers with very low cation mixing. The low cation mixing results from the cation confinement by the novel "egg-box" structure in the alginate template. These hollow fibers exhibit remarkable energy density, high-rate capacity, and long-term cycling stability when used as cathode material for Li-ion batteries.

Nitrogen-doped porous carbon nanosheets (N-CNS) are synthesized by hydrothermal carbon coating of g-C3 N4 nanosheets followed by high-temperature treatment in N2 . g-C3 N4 serves as a template, nitrogen source, and porogen in the synthesis. This approach yields N-CNS with a high nitrogen content and comparable oxygen reduction reaction catalytic activities to commercial Pt/C catalysts in alkaline media., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

T. Zhang and co-workers report the synthesis of nitrogen-doped porous carbon nanosheets with extremely high nitrogen content and high surface areas using graphitic carbon nitride (g-C3 N4 ) as template, nitrogen source, and porogen. As described on page 5080, the nanosheets exhibit outstanding oxygen reduction catalytic activities which are comparable to commercial Pt/C catalysts in alkaline media., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A well-dispersed Co,N co-doped carbon nanoframework (Co,N-CNF) with hierarchically porous structure is successfully synthesized from zeolitic imidazolate framework (ZIF) precursors via a mesoporous-silica-protected calcination strategy. By preventing the irreversible fusion and aggregation during the high-temperature pyrolysis step with this protection strategy, the Co,N-CNF exhibits comparable oxygen reduction reaction (ORR) catalytic activity to that of commercial Pt catalysts with the same loading., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We report an effective and universal approach for the preparation of ultrathin single- or multiple-component transition-metal hydroxide (TMH) nanosheets with thickness below 5 nm. The unique synthesis benefits from the gradual decomposition of the preformed metal-boron (M-B, M=Fe, Co, Ni, NiCo) composite nanospheres which facilitates the formation of ultrathin nanosheets by the oxidation of the metal and the simultaneous release of boron species. The high specific surface area of the sheets associated with their ultrathin nature promises a wide range of applications. For example, we demonstrate the remarkable adsorption ability of Pb(II) and As(V) in waste water by the ultrathin FeOOH nanosheets. More interestingly, the process can be extended simply to the synthesis of composite structures of metal alloy hollow shells encapsulated by TMH nanosheets, which show excellent catalytic activity in the Heck reaction., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Monovalent Zn + (3d 10 4s 1 ) systems possess a special electronic structure that can be exploited in heterogeneous catalysis and photocatalysis, though it remains challenge to synthesize Zn + -containing materials. By careful design, Zn + -related species can be synthesized in zeolite and layered double hydroxide systems, which in turn exhibit excellent catalytic potential in methane, CO and CO 2 activation. Furthermore, by utilizing advanced characterization tools, including electron spin resonance, X-ray absorption fine structure and density functional theory calculations, the formation mechanism of the Zn + species and their structure-performance relationships can be understood. Such advanced characterization tools guide the rational design of high-performance Zn + -containing catalysts for efficient energy conversion.

A novel versatile light-triggered strategy is developed to organize inorganic nanoparticles (NPs) into nanovesicles with single or multiple layers in mixed solvents. This strategy constitutes a new assembly mechanism based on the photo-oxidation of thiol ligands. Compared with currently-used individual semiconductor NPs, the prepared CdSe QD vesicles exhibit an improved catalytic activity and unprecedented catalytic stability towards solar-driven hydrogen production. This light-triggered approach to functional nanoarchitectures would lead to new opportunities in various applications., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Dengue is a systemic viral infection that is transmitted to humans by Aedes mosquitoes. No vaccines or specific therapeutics are currently available for dengue. Lycorine, which is a natural plant alkaloid, has been shown to possess antiviral activities against flaviviruses. In this study, a series of novel lycorine derivatives were synthesized and assayed for their inhibition of dengue virus (DENV) in cell cultures. Among the lycorine analogues, 1-acetyllycorine exhibited the most potent anti-DENV activity (EC50 =0.4 μM) with a reduced cytotoxicity (CC50 >300 μM), which resulted in a selectivity index (CC50 /EC50 ) of more than 750. The ketones 1-acetyl-2-oxolycorine (EC50 =1.8 μM) and 2-oxolycorine (EC50 =0.5 μM) also exhibited excellent antiviral activities with low cytotoxicity. Structure-activity relationships for the lycorine derivatives against DENV are discussed. A three-dimensional quantitative structure-activity relationship model was established by using a comparative molecular-field analysis protocol in order to rationalize the experimental results. Further modifications of the hydroxy group at the C1 position with retention of a ketone at the C2 position could potentially lead to inhibitors with improved overall properties., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Graphene nanosheet-supported ultrafine metal nanoparticles encapsulated by thin mesoporous SiO2 layers were prepared and used as robust catalysts with high catalytic activity and excellent high-temperature stability. The catalysts can be recycled and reused in many gas- and solution-phase reactions, and their high catalytic activity can be fully recovered by high-temperature regeneration, should they be deactivated by feedstock poisoning. In addition to the large surface area provided by the graphene support, the enhanced catalytic performance is also attributed to the mesoporous SiO2 layers, which not only stabilize the ultrafine metal nanoparticles, but also prevent the aggregation of the graphene nanosheets. The synthetic strategy can be extended to other metals, such as Pd and Ru, for preparing robust catalysts for various reactions., (Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A new type of nanoscale bioswitch based on the electrical detection of chemically induced cleavage of chemical bonds, which bind individual nanowires across a pair of electrodes is demonstrated. Carbon nanofibers are manipulated using dielectrophoresis to form single-nanowire bridges across microelectrode junctions, and are anchored through a biomolecular interaction. Once in place, chemically induced cleavage of a recognition site along the bonds linking the nanowire to the electrodes allows the nanowire to be easily removed by a flow of fluid; this removal can be detected in real time via changes in the AC electrical response. This form of sensing is inherently digital in nature as the removal of a single nanowire produces a sudden decrease in the current between electrodes and is essentially a chemoselective fuse. These results suggest that this sensing principle could be a general method for digital chemical and/or biological sensing using individual nanowires.

Dielectrophoretic manipulation of nanoscale materials is typically performed in nonionic, highly insulating solvents. However, biomolecular recognition processes, such as DNA hybridization and protein binding, typically operate in highly conducting, aqueous saline solutions. Here, we report investigations of the manipulation and real-time detection of individual nanowires bridging microelectrode gaps in saline solutions. Measurements of the electrode impedance versus frequency show a crossover in behavior at a critical frequency that is dependent on the ionic strength. We demonstrate that by operating above this critical frequency, it is possible to use dielectrophoresis to manipulate nanowires across electrode gaps in saline solutions. By using electrical ground planes and nulling schemes to reduce the background currents, we further demonstrate the ability to electrically detect bridging and unbridging events of individual nanowires in saline solutions. The ability to both manipulate and detect bridging events with electrical signals provides a pathway toward automated assembly of nanoscale devices that incorporate biomolecular recognition elements.