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Encapsulating transition‐metal nanoparticles inside carbon nanotubes (CNTs) or spheres has emerged as a novel strategy for designing highly durable nonprecious‐metal catalysts. The stable carbon layer protects the inner metal core from the destructive reaction environment and thus is described as chain mail for catalysts. Electron transfer from the active metal core to the carbon layer stimulates unique catalytic activity on the carbon surface, which has been utilized extensively in a variety of catalytic reaction systems. Here, we elaborate the underlying working principle of chain mail for catalysts as well as the key factors that determine their catalytic properties, and provide insights into the physicochemical nature of such catalyst architectures for further application of the strategy in rational catalyst design. [ABSTRACT FROM AUTHOR]

Encapsulating transition‐metal nanoparticles inside carbon nanotubes (CNTs) or spheres has emerged as a novel strategy for designing highly durable nonprecious‐metal catalysts. The stable carbon layer protects the inner metal core from the destructive reaction environment and thus is described as chain mail for catalysts. Electron transfer from the active metal core to the carbon layer stimulates unique catalytic activity on the carbon surface, which has been utilized extensively in a variety of catalytic reaction systems. Here, we elaborate the underlying working principle of chain mail for catalysts as well as the key factors that determine their catalytic properties, and provide insights into the physicochemical nature of such catalyst architectures for further application of the strategy in rational catalyst design. [ABSTRACT FROM AUTHOR]

Chainmail for catalysts: A catalyst with iron nanoparticles confined inside pea‐pod‐like carbon nanotubes (see picture) exhibits a high activity and remarkable stability as a cathode catalyst in polymer electrolyte membrane fuel cells (PEMFC), even in presence of SO2. The approach offers a new route to electro‐ and heterogeneous catalysts for harsh conditions. [ABSTRACT FROM AUTHOR]

Kettenhemd für Katalysatoren: Kohlenstoffnanoröhren mit Eisen ‐ Nanopartikeln in ihrem Inneren (siehe Schema) sind hoch aktive Kathodenkatalysatoren in Polymerelektrolytmembran ‐ Brennstoffzellen. Nach diesem Vorbild könnten effiziente und stabile Katalysatoren für elektro ‐ und heterogenkatalysierte Prozesse unter harschen Bedingungen entwickelt werden. [ABSTRACT FROM AUTHOR]

Abstract: Hydrophilic nanographene (NGP) prepared by ball milling of graphite was used as the support to construct a novel tyrosinase biosensor for determination of bisphenol A (BPA). The performances of the nanographene-based tyrosinase biosensor were systematically compared with those of multiwall carbon nanotubes (MWNTs) modified tyrosinase biosensors. The results indicated that the nanographene-based tyrosinase biosensor provided significant advantages over MWNTs-based tyrosinase biosensor in term of response, repeatability, background current and limit of detection (LOD), which could be attributed to its larger specific surface area and unique hierarchical tyrosinase-NGP nanostructures. The nanographene-based tyrosinase biosensor displayed superior analytical performance over a linear range from 100nmolL−1 to 2000nmolL−1, with LOD of 33nmolL−1 and sensitivity of 3108.4mAcm−2 M−1. The biosensor was further used for detecting BPA (leaching from different vessels) in tap water, and the accuracy of the results was validated by high performance liquid chromatography (HPLC). The nanographene-based tyrosinase biosensor proved to be a promising and reliable tool for rapid detection of BPA leached from polycarbonate plastic products and for on-site rapid analysis of emergency pollution affairs of BPA. [Copyright &y& Elsevier]

Abstract: Hierarchical mesoporous ZrO2-carbon fiber was successfully synthesized by using collagen fiber as a structure-directing agent, and characterized by scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The ZrO2-carbon fiber obtained is approximately 1–4μm in outer diameter and 0.5–1mm in length, and the surface of the fiber exhibits ordered corn-cob-like mesoporous morphology. [Copyright &y& Elsevier]

Synthesis of formate from hydrogenation of carbon dioxide (CO2) is an atom‐economic reaction but is confronted with challenges in developing high‐performance non‐precious metal catalysts for application of the process. Herein, we report a highly durable edge‐rich molybdenum disulfide (MoS2) catalyst for CO2 hydrogenation to formate at 200 °C, which delivers a high selectivity of over 99 % with a superior turnover frequency of 780.7 h−1 surpassing those of previously reported non‐precious metal catalysts. Multiple experimental characterization techniques combined with theoretical calculations reveal that sulfur vacancies at MoS2 edges are the active sites and the selective production of formate is enabled via a completely new water‐mediated hydrogenation mechanism, in which surface OH* and H* species in dynamic equilibrium with water serve as moderate hydrogenating agents for CO2 with residual O* reduced by hydrogen. This study provides a new route for developing low‐cost high‐performance catalysts for CO2 hydrogenation to formate. [ABSTRACT FROM AUTHOR]

Synthesis of formate from hydrogenation of carbon dioxide (CO2) is an atom‐economic reaction but is confronted with challenges in developing high‐performance non‐precious metal catalysts for application of the process. Herein, we report a highly durable edge‐rich molybdenum disulfide (MoS2) catalyst for CO2 hydrogenation to formate at 200 °C, which delivers a high selectivity of over 99 % with a superior turnover frequency of 780.7 h−1 surpassing those of previously reported non‐precious metal catalysts. Multiple experimental characterization techniques combined with theoretical calculations reveal that sulfur vacancies at MoS2 edges are the active sites and the selective production of formate is enabled via a completely new water‐mediated hydrogenation mechanism, in which surface OH* and H* species in dynamic equilibrium with water serve as moderate hydrogenating agents for CO2 with residual O* reduced by hydrogen. This study provides a new route for developing low‐cost high‐performance catalysts for CO2 hydrogenation to formate. [ABSTRACT FROM AUTHOR]

Review: 149 refs. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction reaction (CO2RR) in membrane electrode assembly (MEA) systems is a promising technology. Gaseous CO2 can be directly transported to the cathode catalyst layer, leading to enhanced reaction rate. Meanwhile, there is no liquid electrolyte between the cathode and the anode, which can help to improve the energy efficiency of the whole system. The remarkable progress achieved recently points out the way to realize industrially relevant performance. In this review, we focus on the principles in MEA for CO2RR, focusing on gas diffusion electrodes and ion exchange membranes. Furthermore, anode processes beyond the oxidation of water are considered. Besides, the voltage distribution is scrutinized to identify the specific losses related to the individual components. We also summarize the progress on the generation of different reduced products together with the corresponding catalysts. Finally, the challenges and opportunities are highlighted for future research. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction reaction (CO2RR) in membrane electrode assembly (MEA) systems is a promising technology. Gaseous CO2 can be directly transported to the cathode catalyst layer, leading to enhanced reaction rate. Meanwhile, there is no liquid electrolyte between the cathode and the anode, which can help to improve the energy efficiency of the whole system. The remarkable progress achieved recently points out the way to realize industrially relevant performance. In this review, we focus on the principles in MEA for CO2RR, focusing on gas diffusion electrodes and ion exchange membranes. Furthermore, anode processes beyond the oxidation of water are considered. Besides, the voltage distribution is scrutinized to identify the specific losses related to the individual components. We also summarize the progress on the generation of different reduced products together with the corresponding catalysts. Finally, the challenges and opportunities are highlighted for future research. [ABSTRACT FROM AUTHOR]

Metallic conductive 1T phase molybdenum sulfide (MoS2) has been identified as promising anode for sodium ion (Na+) batteries, but its metastable feature makes it difficult to obtain and its restacking during the charge/discharge processing result in part capacity reversibility. Herein, a synergetic effect of atomic‐interface engineering is employed for constructing 2H‐MoS2 layers assembled on single atomically dispersed Fe−N−C (SA Fe−N−C) anode material that boosts its reversible capacity. The work‐function‐driven‐electron transfer occurs from SA Fe−N−C to 2H‐MoS2 via the Fe−S bonds, which enhances the adsorption of Na+ by 2H‐MoS2, and lays the foundation for the sodiation process. A phase transfer from 2H to 1T/2H MoS2 with the ferromagnetic spin‐polarization of SA Fe−N−C occurs during the sodiation/desodiation process, which significantly enhances the Na+ storage kinetics, and thus the 1T/2H MoS2/SA Fe−N−C display a high electronic conductivity and a fast Na+ diffusion rate. [ABSTRACT FROM AUTHOR]

Metallic conductive 1T phase molybdenum sulfide (MoS2) has been identified as promising anode for sodium ion (Na+) batteries, but its metastable feature makes it difficult to obtain and its restacking during the charge/discharge processing result in part capacity reversibility. Herein, a synergetic effect of atomic‐interface engineering is employed for constructing 2H‐MoS2 layers assembled on single atomically dispersed Fe−N−C (SA Fe−N−C) anode material that boosts its reversible capacity. The work‐function‐driven‐electron transfer occurs from SA Fe−N−C to 2H‐MoS2 via the Fe−S bonds, which enhances the adsorption of Na+ by 2H‐MoS2, and lays the foundation for the sodiation process. A phase transfer from 2H to 1T/2H MoS2 with the ferromagnetic spin‐polarization of SA Fe−N−C occurs during the sodiation/desodiation process, which significantly enhances the Na+ storage kinetics, and thus the 1T/2H MoS2/SA Fe−N−C display a high electronic conductivity and a fast Na+ diffusion rate. [ABSTRACT FROM AUTHOR]

As key components of air, nitrogen (N2) and oxygen (O2) are the vital constituents of lives. Synthesis of NO2, and C–N–O organics direct from N2 and O2, rather than from an intermediate NH3 (known as the Haber–Bosch process), is tantalizing. However, the extremely strong N≡N triple bond (945 kJ mol–1) and the nonpolar stable electron configuration of dinitrogen lead to its conversion being extensively energy demanding. The further selective synthesis of high-value C–N–O organics directly from N2, O2 and C-containing molecules is attractive yet greatly challenging from both scientific and engineering perspectives. Enormous efforts have been dedicated to the direct conversion of N2 and O2 via traditional and novel techniques, including thermochemical, plasma, electrochemical, ultrasonic and photochemical conversion. In this review, we aim to provide a thorough comprehension of the status and challenge of the direct conversion of N2, O2 and C-containing molecules (particularly N2 and O2). Moreover, we will propose some future perspectives to stimulate more inspiration from the scientific community to tackle the scientific and engineering challenges. [ABSTRACT FROM AUTHOR]

Major challenges encountered when trying to replace precious-metal-based electrocatalysts of the hydrogen evolution reaction (HER) in acidic media are related to the low efficiency and stability of non-precious-metal compounds. Therefore, new concepts and strategies have to be devised to develop electrocatalysts that are based on earth-abundant materials. Herein, we report a hierarchical architecture that consists of ultrathin graphene shells (only 1-3 layers) that encapsulate a uniform CoNi nanoalloy to enhance its HER performance in acidic media. The optimized catalyst exhibits high stability and activity with an onset overpotential of almost zero versus the reversible hydrogen electrode (RHE) and an overpotential of only 142 mV at 10 mA cm−2, which is quite close to that of commercial 40 % Pt/C catalysts. Density functional theory (DFT) calculations indicate that the ultrathin graphene shells strongly promote electron penetration from the CoNi nanoalloy to the graphene surface. With nitrogen dopants, they synergistically increase the electron density on the graphene surface, which results in superior HER activity on the graphene shells. [ABSTRACT FROM AUTHOR]

Major challenges encountered when trying to replace precious-metal-based electrocatalysts of the hydrogen evolution reaction (HER) in acidic media are related to the low efficiency and stability of non-precious-metal compounds. Therefore, new concepts and strategies have to be devised to develop electrocatalysts that are based on earth-abundant materials. Herein, we report a hierarchical architecture that consists of ultrathin graphene shells (only 1-3 layers) that encapsulate a uniform CoNi nanoalloy to enhance its HER performance in acidic media. The optimized catalyst exhibits high stability and activity with an onset overpotential of almost zero versus the reversible hydrogen electrode (RHE) and an overpotential of only 142 mV at 10 mA cm−2, which is quite close to that of commercial 40 % Pt/C catalysts. Density functional theory (DFT) calculations indicate that the ultrathin graphene shells strongly promote electron penetration from the CoNi nanoalloy to the graphene surface. With nitrogen dopants, they synergistically increase the electron density on the graphene surface, which results in superior HER activity on the graphene shells. [ABSTRACT FROM AUTHOR]

[Display omitted] Fully inactivating SARS-CoV-2, the virus causing coronavirus disease 2019, is of key importance for interrupting virus transmission but is currently performed by using biologically or environmentally hazardous disinfectants. Herein, we report an eco-friendly and efficient electrochemical strategy for inactivating the SARS-CoV-2 using in-situ formed nickel oxide hydroxide as anode catalyst and sodium carbonate as electrolyte. At a voltage of 5 V, the SARS-CoV-2 viruses can be rapidly inactivated with disinfection efficiency reaching 95% in only 30 s and 99.99% in 5 min. Mass spectrometry analysis and theoretical calculations indicate that the reactive oxygen species generated on the anode can oxidize the peptide chains and induce cleavage of the peptide backbone of the receptor binding domain of the SARS-CoV-2 spike glycoprotein, and thereby disables the virus. This strategy provides a sustainable and highly efficient approach for the disinfection of the SARS-CoV-2 viruliferous aerosols and wastewater. [ABSTRACT FROM AUTHOR]

Keywords: Carbon Dioxide Conversion; Heterogeneous Catalysis; Materials Science; Reaction Mechanisms; Reduction EN Carbon Dioxide Conversion Heterogeneous Catalysis Materials Science Reaction Mechanisms Reduction 1 1 1 10/31/23 20231106 NES 231106 B CO SB 2 sb hydrogenation to formate b is an attractive route for the utilization of this greenhouse gas. Comprehensive mechanism studies reveal that selective production of formate is enabled at MoS SB 2 sb edge sulfur vacancies via a new water-mediated hydrogenation mechanism. Carbon Dioxide Conversion, Heterogeneous Catalysis, Materials Science, Reaction Mechanisms, Reduction. [Extracted from the article]

Keywords: Carbon Dioxide Conversion; Heterogeneous Catalysis; Materials Science; Reaction Mechanisms; Reduction EN Carbon Dioxide Conversion Heterogeneous Catalysis Materials Science Reaction Mechanisms Reduction 1 1 1 10/31/23 20231106 NES 231106 B Sn-based perovskite oxides b have shown intriguing potential in CO SB 2 sb electroreduction. Carbon Dioxide Conversion, Heterogeneous Catalysis, Materials Science, Reaction Mechanisms, Reduction In their Research Article (e202307086), Jiawei Zhu and co-workers report an effective strategy to promote CO SB 2 sb -to-HCOOH conversion of Sn-based perovskite oxides by A-site-radius-controlled Sn-O bond lengths. [Extracted from the article]

Early identification of infection severity and organ dysfunction is crucial in improving outcomes of patients with sepsis. We aimed to develop a new combination of blood-based biomarkers that can early predict 28-day mortality in patients with sepsis or septic shock. We enrolled 66 patients with sepsis or septic shock and compared 14 blood-based biomarkers in the first 24 h after ICU admission. The serum levels of interleukin-6 (IL-6) (median 217.6 vs. 4809.0 pg/ml, P = 0.001), lactate (median 2.4 vs. 6.3 mmol/L, P = 0.014), N-terminal prohormone of brain natriuretic peptide (NT-proBNP) (median 1596.5 vs. 32,905.3 ng/ml, P < 0.001), prothrombin time (PT) (median 15.6 vs. 20.1 s, P = 0.030), activated partial thrombin time (APTT) (median 45.1 vs. 59.0 s, P = 0.026), and international normalized ratio (INR) (median 1.3 vs. 1.8, P < 0.001) were significantly lower in the survivor group. IL-6, NT-proBNP, and INR provided the best individual performance in predicting 28-day mortality of patients with sepsis or septic shock. Furthermore, the combination of these three biomarkers achieved better predictive performance (AUC 0.890, P < 0.001) than conventional scoring systems. In summary, the combination of IL-6, NT-proBNP, and INR may serve as a potential predictor of 28-day mortality in critically ill patients with sepsis or septic shock. [ABSTRACT FROM AUTHOR]

N -containing organic compounds are of vital importance to lives. Practical synthesis of valuable N -containing organic compounds directly from dinitrogen (N2), not through ammonia (NH3), is a holy-grail in chemistry and chemical industry. An essential step for this transformation is the functionalization of the activated N2 units/ligands to generate N−C bonds. Pioneering works of transition metal-mediated direct conversion of N2 into organic compounds via N−C bond formation at metal-dinitrogen [N2-M] complexes have generated diversified coordination modes and laid the foundation of understanding for the N−C bond formation mechanism. This review summarizes those major achievements and is organized by the coordination modes of the [N2-M] complexes (end-on, side-on, end-on-side-on, etc.) that are involved in the N−C bond formation steps, and each part is arranged in terms of reaction types (N -alkylation, N -acylation, cycloaddition, insertion, etc.) between [N2-M] complexes and carbon-based substrates. Additionally, earlier works on one-pot synthesis of organic compounds from N2 via ill-defined intermediates are also briefed. Although almost all of the syntheses of N -containing organic compounds via direct transformation of N2 so far in the literature are realized in homogeneous stoichiometric thermochemical reaction systems and are discussed here in detail, the sporadically reported syntheses involving photochemical, electrochemical, heterogeneous thermo-catalytic reactions, if any, are also mentioned. This review aims to provide readers with an in-depth understanding of the state-of-the-art and perspectives of future research particularly in direct catalytic and efficient conversion of N2 into N -containing organic compounds under mild conditions, and to stimulate more research efforts to tackle this long-standing and grand scientific challenge. [ABSTRACT FROM AUTHOR]

Perturbing the electronic structure of the MoS2 basal plane by confining heteroatoms offers the opportunity to trigger in‐plane activity for the hydrogen evolution reaction (HER). The key challenge consists of inducing the optimum HER activity by controlling the type and distribution of confined atoms. A distance synergy of MoS2‐confined single‐atom rhodium is presented, leading to an ultra‐high HER activity at the in‐plane S sites adjacent to the rhodium. By optimizing the distance between the confined Rh atoms, an ultra‐low overpotential of 67 mV is achieved at a current density of 10 mA cm−2 in acidic solution. Experiments and first‐principles calculations demonstrate a unique distance synergy between the confined rhodium atoms in tuning the reactivity of neighboring in‐plane S atoms, which presents a volcanic trend with the inter‐rhodium distance. This study provides a new strategy to tailor the activity of MoS2 surface via modulating the distance between confined single atoms. [ABSTRACT FROM AUTHOR]

Perturbing the electronic structure of the MoS2 basal plane by confining heteroatoms offers the opportunity to trigger in‐plane activity for the hydrogen evolution reaction (HER). The key challenge consists of inducing the optimum HER activity by controlling the type and distribution of confined atoms. A distance synergy of MoS2‐confined single‐atom rhodium is presented, leading to an ultra‐high HER activity at the in‐plane S sites adjacent to the rhodium. By optimizing the distance between the confined Rh atoms, an ultra‐low overpotential of 67 mV is achieved at a current density of 10 mA cm−2 in acidic solution. Experiments and first‐principles calculations demonstrate a unique distance synergy between the confined rhodium atoms in tuning the reactivity of neighboring in‐plane S atoms, which presents a volcanic trend with the inter‐rhodium distance. This study provides a new strategy to tailor the activity of MoS2 surface via modulating the distance between confined single atoms. [ABSTRACT FROM AUTHOR]

NO removal from exhausted gas is necessary owing to its damage to environment. Meanwhile, the electrochemical ammonia synthesis (EAS) from N2 suffers from low reaction rate and Faradaic efficiency (FE). Now, an alternative route for ammonia synthesis is proposed from exhaust NO via electrocatalysis. DFT calculations indicate electrochemical NO reduction (NORR) is more active than N2 reduction (NRR). Via a descriptor‐based approach, Cu was screened out to be the most active transition metal catalyst for NORR to NH3 owing to its moderate reactivity. Kinetic barrier calculations reveal NH3 is the most preferred product relative to H2, N2O, and N2 on Cu. Experimentally, a record‐high EAS rate of 517.1 μmol cm−2 h−1 and FE of 93.5 % were achieved at −0.9 V vs. RHE using a Cu foam electrode, exhibiting stable electrocatalytic performances with a 100 h run. This work provides an alternative strategy to EAS from exhaust NO, coupled with NO removal. [ABSTRACT FROM AUTHOR]

NO removal from exhausted gas is necessary owing to its damage to environment. Meanwhile, the electrochemical ammonia synthesis (EAS) from N2 suffers from low reaction rate and Faradaic efficiency (FE). Now, an alternative route for ammonia synthesis is proposed from exhaust NO via electrocatalysis. DFT calculations indicate electrochemical NO reduction (NORR) is more active than N2 reduction (NRR). Via a descriptor‐based approach, Cu was screened out to be the most active transition metal catalyst for NORR to NH3 owing to its moderate reactivity. Kinetic barrier calculations reveal NH3 is the most preferred product relative to H2, N2O, and N2 on Cu. Experimentally, a record‐high EAS rate of 517.1 μmol cm−2 h−1 and FE of 93.5 % were achieved at −0.9 V vs. RHE using a Cu foam electrode, exhibiting stable electrocatalytic performances with a 100 h run. This work provides an alternative strategy to EAS from exhaust NO, coupled with NO removal. [ABSTRACT FROM AUTHOR]

Conversion of carbon monoxide to high value‐added ethylene with high selectivity by traditional syngas conversion process is challenging because of the limitation of Anderson‐Schulz–Flory distribution. Herein we report a direct electrocatalytic process for highly selective ethylene production from CO reduction with water over Cu catalysts at room temperature and ambient pressure. An unprecedented 52.7 % Faradaic efficiency of ethylene formation is achieved through optimization of cathode structure to facilitate CO diffusion at the surface of the electrode and Cu catalysts to enhance the C−C bond coupling. The highly selective ethylene production is almost without other carbon‐based byproducts (e.g. C1–C4 hydrocarbons and CO2) and avoids the drawbacks of the traditional Fischer–Tropsch process that always delivers undesired products. This study provides a new and promising strategy for highly selective production of ethylene from the abundant industrial CO. [ABSTRACT FROM AUTHOR]

Conversion of carbon monoxide to high value‐added ethylene with high selectivity by traditional syngas conversion process is challenging because of the limitation of Anderson‐Schulz–Flory distribution. Herein we report a direct electrocatalytic process for highly selective ethylene production from CO reduction with water over Cu catalysts at room temperature and ambient pressure. An unprecedented 52.7 % Faradaic efficiency of ethylene formation is achieved through optimization of cathode structure to facilitate CO diffusion at the surface of the electrode and Cu catalysts to enhance the C−C bond coupling. The highly selective ethylene production is almost without other carbon‐based byproducts (e.g. C1–C4 hydrocarbons and CO2) and avoids the drawbacks of the traditional Fischer–Tropsch process that always delivers undesired products. This study provides a new and promising strategy for highly selective production of ethylene from the abundant industrial CO. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction to CO emerges as a potential route of utilizing emitted CO2. Metal‐N‐C hybrid structures have shown unique activities, however, the active centers and reaction mechanisms remain unclear because of the ambiguity in true atomic structures for the prepared catalysts. Herein, combining density‐functional theory calculations and experimental studies, the reaction mechanisms for well‐defined metal–N4 sites were explored using metal phthalocyanines as model catalysts. The theoretical calculations reveal that cobalt phthalocyanine exhibits the optimum activity for CO2 reduction to CO because of the moderate *CO binding energy at the Co site, which accommodates the *COOH formation and the *CO desorption. It is further confirmed by experimental studies, where cobalt phthalocyanine delivers the best performance, with a maximal CO Faradaic efficiency reaching 99 %, and maintains stable performance for over 60 hours. To the "CO2RR": Metal phthalocyanines (MePcs) with well‐defined metal–N4 structures were used as model catalysts to study the active centers and reaction mechanisms for the electrocatalytic CO2 reduction reaction (CO2RR). Theoretical and experimental studies identify CoPc as the optimum catalyst for the selective electrocatalytic CO2RR to deliver CO. The Co site serves as the active center for achieving a Faradaic efficiency (FE) of up to 99 % with long‐term stability. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction to CO emerges as a potential route of utilizing emitted CO2. Metal‐N‐C hybrid structures have shown unique activities, however, the active centers and reaction mechanisms remain unclear because of the ambiguity in true atomic structures for the prepared catalysts. Herein, combining density‐functional theory calculations and experimental studies, the reaction mechanisms for well‐defined metal–N4 sites were explored using metal phthalocyanines as model catalysts. The theoretical calculations reveal that cobalt phthalocyanine exhibits the optimum activity for CO2 reduction to CO because of the moderate *CO binding energy at the Co site, which accommodates the *COOH formation and the *CO desorption. It is further confirmed by experimental studies, where cobalt phthalocyanine delivers the best performance, with a maximal CO Faradaic efficiency reaching 99 %, and maintains stable performance for over 60 hours. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A series of MN x /C- T catalysts were prepared by a two-step calcination approach. • FeN x /C-900 exhibits high performance in selective oxidation of unsaturated alcohols. • The selective oxidation mainly occurs on the Fe N 4 species in FeN x /C-900. • Catalyst deactivation occurs essentially due to the loss of nitrogen species. • The spent catalyst can be regenerated by treatment under NH 3 /N 2. Abstract Transition-metal nitrides can exhibit catalytic performance comparable to that of noble metal catalysts in many reactions. However, investigations on the correlation of catalyst structure, performance, and stability are still highly demanded. Here, a series of metal nitrides were prepared and evaluated for the selective oxidation of alcohols by molecular oxygen. Among them, FeN x /C- T catalysts (T represents the pyrolysis temperature) display above 95% selectivity to the corresponding aldehydes in the selective oxidation of unsaturated alcohols. The optimized FeN x /C-900 catalyst gives the highest TOF of 7.0 h−1 for the conversion of 5-hydroxymethylfurfural to 2,5-diformylfuran. A combination of characterizations and experiments suggests that Fe N 4 species are the main active sites. In addition, we investigate the reasons for the catalyst deactivation and provide an effective approach to regenerating the catalysts. The results indicate that the deactivated catalysts can be regenerated by heat treatment under NH 3 /N 2 after each run. Based on these studies, a plausible reaction mechanism over the FeN x /C catalysts is proposed. [ABSTRACT FROM AUTHOR]

Atomic scale characterization of the surface structure of powder catalysts is essential to the identification of active sites, but remains a major challenge in catalysis research. We described here a procedure that combines atomic force microscopy (AFM), operated in air, and scanning tunneling microscopy (STM), operated in UHV, to obtain the atomic structure and local electronic properties of powder catalysts. The atomically dispersed Fe-N-C catalyst was used as an example, which was synthesized by low temperature ball milling methods. We discussed the effect of solvents in the dispersion of powder catalysts on a planar support, which is key to the subsequent atomic characterization. From the morphology, atomic structure and local electronic properties of the Fe-N-C catalyst, our combined measurements also provide an insight for the effect of ball milling in the preparation of atomically dispersed metal catalysts. [ABSTRACT FROM AUTHOR]

The design of catalysts that are both highly active and stable is always challenging. Herein, we report that the incorporation of single metal active sites attached to the nitrogen atoms in the basal plane of graphene leads to composite materials with superior activity and stability when used as counter electrodes in dye-sensitized solar cells (DSSCs). A series of composite materials based on different metals (Mn, Fe, Co, Ni, and Cu) were synthesized and characterized. Electrochemical measurements revealed that CoN4/GN is a highly active and stable counter electrode for the interconversion of the redox couple I−/I3−. DFT calculations revealed that the superior properties of CoN4/GN are due to the appropriate adsorption energy of iodine on the confined Co sites, leading to a good balance between adsorption and desorption processes. Its superior electrochemical performance was further confirmed by fabricating DSSCs with CoN4 /GN electrodes, which displayed a better power conversion efficiency than the Pt counterpart. [ABSTRACT FROM AUTHOR]

The design of catalysts that are both highly active and stable is always challenging. Herein, we report that the incorporation of single metal active sites attached to the nitrogen atoms in the basal plane of graphene leads to composite materials with superior activity and stability when used as counter electrodes in dye-sensitized solar cells (DSSCs). A series of composite materials based on different metals (Mn, Fe, Co, Ni, and Cu) were synthesized and characterized. Electrochemical measurements revealed that CoN4/GN is a highly active and stable counter electrode for the interconversion of the redox couple I−/I3−. DFT calculations revealed that the superior properties of CoN4/GN are due to the appropriate adsorption energy of iodine on the confined Co sites, leading to a good balance between adsorption and desorption processes. Its superior electrochemical performance was further confirmed by fabricating DSSCs with CoN4 /GN electrodes, which displayed a better power conversion efficiency than the Pt counterpart. [ABSTRACT FROM AUTHOR]

Podlike nitrogen-doped carbon nanotubes encapsulating FeNi alloy nanoparticles (Pod(N)-FeNi) were prepared by the direct pyrolysis of organometallic precursors. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel polarization measurements revealed their excellent electrocatalytic activities in the I−/I3− redox reaction of dye-sensitized solar cells (DSSCs). This is suggested to arise from the modification of the surface electronic properties of the carbon by the encapsulated metal alloy nanoparticles (NPs). Sequential scanning with EIS and CV further showed the high electrochemical stability of the Pod(N)-FeNi composite. DSSCs with Pod(N)-FeNi as the counter electrode (CE) presented a power conversion efficiency of 8.82 %, which is superior to that of the control device with sputtered Pt as the CE. The Pod(N)-FeNi composite thus shows promise as an environmentally friendly, low-cost, and highly efficient CE material for DSSCs. [ABSTRACT FROM AUTHOR]

Podlike nitrogen-doped carbon nanotubes encapsulating FeNi alloy nanoparticles (Pod(N)-FeNi) were prepared by the direct pyrolysis of organometallic precursors. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel polarization measurements revealed their excellent electrocatalytic activities in the I−/I3− redox reaction of dye-sensitized solar cells (DSSCs). This is suggested to arise from the modification of the surface electronic properties of the carbon by the encapsulated metal alloy nanoparticles (NPs). Sequential scanning with EIS and CV further showed the high electrochemical stability of the Pod(N)-FeNi composite. DSSCs with Pod(N)-FeNi as the counter electrode (CE) presented a power conversion efficiency of 8.82 %, which is superior to that of the control device with sputtered Pt as the CE. The Pod(N)-FeNi composite thus shows promise as an environmentally friendly, low-cost, and highly efficient CE material for DSSCs. [ABSTRACT FROM AUTHOR]

The incorporation of single cobalt active sites within a graphene matrix leads to a composite material with superior activity and stability when used as a counter electrode for the interconversion of the redox couple I−/I3−. In their Communication on page 6708 ff., D. Deng, W.‐H. Zhang, and co‐workers further show that the use of this material as a counter electrode in a dye‐sensitized solar cell (DSSC) leads to a better power conversion efficiency than the use of a platinum counter electrode. [ABSTRACT FROM AUTHOR]

Der Einbau einzelner aktiver Cobaltzentren in eine Graphenmatrix ergibt eine aktive und stabile Gegenelektrode für die Redoxreaktion I−/I3−. In der Zuschrift auf S. 6820 ff. zeigen D. Deng, W. ‐ H. Zhang et al. zudem, dass die Verwendung dieser Gegenelektrode anstelle einer Platingegenelektrode in Farbstoffsolarzellen (DSSCs) eine effizientere Stromumwandlung zur Folge hat. [ABSTRACT FROM AUTHOR]