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Metal‐organic frameworks recently have been burgeoning and used as precursors to obtain various metal–nitrogen–carbon catalysts for oxygen reduction reaction (ORR). Although rarely studied, Mn–N–C is a promising catalyst for ORR due to its weak Fenton reaction activity and strong graphitization catalysis. Here, we developed a facile strategy for anchoring the atomically dispersed nitrogen‐coordinated single Mn sites on carbon nanosheets (MnNCS) from an Mn‐hexamine coordination framework. The atomically dispersed Mn–N4 sites were dispersed on ultrathin carbon nanosheets with a hierarchically porous structure. The optimized MnNCS displayed an excellent ORR performance in half‐cells (0.89 V vs. reversible hydrogen electrode (RHE) in base and 0.76 V vs. RHE in acid in half‐wave potential) and Zn–air batteries (233 mW cm−2 in peak power density), along with significantly enhanced stability. Density functional theory calculations further corroborated that the Mn–N4–C12 site has favorable adsorption of *OH as the rate‐determining step. These findings demonstrate that the metal‐hexamine coordination framework can be used as a model system for the rational design of highly active atomic metal catalysts for energy applications. [ABSTRACT FROM AUTHOR]

Ethylbenzene (EB) oxidation to oxygenated products catalyzed by carbon nanotubes (CNTs) and CNTs with confined cobalt nanoparticles (Co@C/CNTs) are conducted. Co@C/CNTs with enhanced interfacial charge transfer displays a unique activity. A kinetic model with the simplified network is established, in which seven elementary reactions with prominent features of EB oxidation are selected. The main parameters, reaction rate constant (k) and active energy (Ea) are obtained. Co@C/CNTs could speed up most elementary steps and reduce energy barriers, thus improving the overall activity. The homolytic cleavage of peroxide is confirmed to be the rate‐determining step (RDS). The k ratio (1.55) of acetophenone (AcPO)/1‐phenylethyl alcohol (PEA) is found to be close to the experimental result (rAcPO/rPEA, 1.30). The prediction of EB oxidation is simulated, showing that the synthesis of AcPO dominates the reaction route, while the addition of PEA would prohibit the reaction. [ABSTRACT FROM AUTHOR]

TiO2 has garnered a flourish of interest in the field of energy storage and energy conversion. Herein, a new generation of 3D Ni foam supported in situ grown 1D TiO2 nanoarray (Ni/TiO2) is successfully prepared, through an easy solution‐phase hydrothermal process, and then CdS nanorods branched Ni/TiO2 nanoarrays are fabricated (Ni/TiO2@CdS). Their formation parameters and growth mechanism are carefully studied. Both Ni/TiO2 and Ni/TiO2@CdS monolithic catalysts exhibit advantaged photocatalytic (PC) and photoelectrocatalytic (PEC) water splitting properties compared with that of most previously reported TiO2‐based film photocatalysts. Mechanism investigation reveals that both type II and Z‐scheme charge transport mechanisms coexist in Ni/TiO2@CdS sample, and an additional Z‐scheme charge transfer effect accelerates the photogenerated charge separation and transport efficiency. This study may open a new avenue for the utilization of TiO2‐based film catalysts in a broader field of energy and environmental catalysis areas. [ABSTRACT FROM AUTHOR]

A high-efficiency and low-cost Zr-based metal–organic frameworks loaded with Co catalyst for the catalytic transfer hydrogenation of biomass-derived 5-hydroxymethylfurfural (HMF) into 2,5-dihydroxymethylfuran (DHMF) through Meerwein–Ponndorf–Verley reduction was developed. A series of Co/UiO-66-NH2 catalysts were synthesised by wet impregnation and reduction using the KBH4 method and characterized by XRD, ICP-OES, XPS, SEM, TEM, BET and TPD techniques. As expected, Co1.6/UiO-66-NH2 displayed high catalytic transfer hydrogenation activity with 92.6% HMF conversion and 95.9% DHMF selectivity at a relatively mild reaction temperature (100 °C) in the presence of isopropanol that served as both hydrogen donor and reaction solvent. The highly dispersed Co species may effectively regulate the acid–base sites of the catalyst, which could be the main reason for the high hydrogenation activity. [ABSTRACT FROM AUTHOR]

Aerobic oxidation of hydrocarbons yielding corresponding oxygenated products is one of the most important chemical processes. In current work, carbon nanotubes supported encapsulated cobalt nanoparticles with carbon layers (Co@C/CNTs) were synthesized and utilized as catalysts in the oxidation of ethylbenzene (EB) in the liquid phase, exhibiting high catalytic performance. The synergistic effect between Co@C and CNTs played the vital role on facilitating the decomposition of peroxides to enhance the overall activity. The inadequate covered Co@C on CNTs surface were considered as catalytic sites. Density functional theory revealed that the exist of Co nanoparticles could improve the interaction between the catalyst and intermediate free radicals, which were significant for EB oxidation. Last but not least, the electron transfer on carbon surface was enhanced by the incorporation of Co@C nanoparticles, which greatly improved the catalytic performance on EB oxidation. This study provides a new insight into the Co‐based catalysts in the aerobic oxidation of hydrocarbons. [ABSTRACT FROM AUTHOR]

The present report focuses on the solvent effect on furfural production from xylose in biphasic systems with methods including combined experiments, molecular dynamics (MD) simulations and density functional theory (DFT) calculations. Six most effective and commonly used biphasic solvents for furfural production were comparatively analyzed and discussed based on the kinetic study, partition coefficient, degradation behavior of furfural in organic solvents, distribution of solvent molecules around xylose/furfural molecules, hydrogen bonding, moving trajectories of xylose/furfural, and the solvation free energy. During the hydrothermal reaction of xylose to furfural in biphasic systems, it was found that the conversion efficiency of biphasic systems can be ordered as DCM/H2O > 2-MTHF/H2O > 2-butanol/H2O ≈ MIBK/H2O > CPME/H2O > toluene/H2O according to the xylose conversion and furfural yield, which are dominated by the solvation free energy (ΔGsol) of furfural in organic solvents, and also be affected by three other factors, namely, the maximum solubility of furfural in organic solvents, the ΔGsol value of organic solvents in water, and the side reaction of furfural in organic solvents. The degradation rate of furfural in 2-butanol was detected to be the fastest, and molecular dynamics simulation data showed that the hydrogen bonding between furfural and 2-butanol may accelerate the degradation of furfural. DCM has excellent extraction ability for furfural, and the maximum furfural yield in the DCM/H2O system (81.64%) is much higher than that in other systems during the hydrothermal reaction without additional catalysts. [ABSTRACT FROM AUTHOR]

The selective oxidation of aromatics to synthesize valued‐added products is of great significance for chemical industry. Molecule oxygen as oxidant is the priority for this process, however, low efficiency was usually obtained. In this work, a new strategy for aromatics oxidation using O2 and Tert‐butyl hydroperoxide (TBHP) as dual oxidants without catalyst was proposed. Typical radical process was observed when Toluene was used as the substrate. As high as 47.1 % conversion and 87.6 % selectivity of benzol acid were obtained, while a negligible or low activity were observed under O2 or TBHP oxidative systems. Detailed investigation shows that the distribution of products was almost the same between TBHP+N2 and TBHP+O2 processes, in which the very close active energies were obtained (46.0 and 46.3 kJ/mol). These results indicated that TBHP+N2 or TBHP+O2 involved reactions underwent the same reaction process. The mechanism study demonstrated that the decomposition of TBHP could produce abundance of t‐BuO. and.OH radicals, which significantly enhanced the αH abstraction from toluene and formed alkyl radicals. The alkyl radicals then react with O2 to produce peroxides, which started the radical propagation cycle. The overall rate would be enhanced subsequently. Furthermore, an extension application of other aromatic substrates was investigated and displayed a great promising future to produce aromatic products. [ABSTRACT FROM AUTHOR]

The electrooxidation of methanol – the anodic reaction of direct methanol fuel cells – suffers from slow kinetics. Here, we report an enhanced current density for a Pt catalyst supported on nitrogen‐doped carbon nanotube (N−CNT) decorated FeP. X‐ray photoelectron spectra show that the introduction of FeP increases the binding energy of the Pt nanoparticles. The results show that Pt/FeP15%/N−CNT displays a 3.4 times higher forward peak current density compared to commercial Pt/C. The improved performance is attributed to a change in the electronic state of the Pt nanoparticles through the electronic interaction between Pt and FeP, evidenced by the mitigated CO poisoning. [ABSTRACT FROM AUTHOR]

Selective hydrogenation of biomass 5‐Hydroxymethylfurfural (HMF) to 2, 5‐dimethylfuran (DMF) which is a suitable candidate for liquid fuel has been widely concerned. Developing efficient and economic catalysts for the hydrogenation of HMF to DMF under mild conditions is a crucial issue. Here series monometallic Cu‐based catalysts were synthesized from controlled thermolysis of Cu‐BTC metal‐organic frameworks and characterized by TG, N2 adsorption‐desorption, XRD, XPS, SEM, TEM, and H2‐TPR techniques. The CuOx@C catalyst with Cu2O/Cu composites enwrapped in porous carbon matrix derived from Cu‐BTC by two steps thermolysis treatment shows high hydrogenation activity with 100% conversion of HMF and 92% selectivity of DMF at 180 °C under 3 MPa H2 pressure. The oxidation treatment following up the thermolysis of Cu‐BTC under inert atmosphere increases the content of Cu+ in the catalyst and improves the activity of the catalyst, which is mainly owe to the synergetic effect between Cu+ and Cu0. [ABSTRACT FROM AUTHOR]

A simple and efficient approach towards α-oxyaminated ketones has been developed through CAN-catalyzed C-O bond formation with 2,2,6,6-tetramethylpiperidine-l-oxyl (TEMPO). The environmentally friendly transformation is practical due to the use of commercial available catalyst, easy operating procedures, the broad substrate scope, and short reaction time. [ABSTRACT FROM AUTHOR]

In this study it is demonstrated that carbon nanotubes (CNTs) with doped nitrogen atoms in graphitic domains (NCNTs) can act as a new class of metal-free catalysts exhibiting excellent activity in the aerobic oxidation of cumene. We proved that NCNTs can promote the decomposition of hydroperoxide cumene with exceptionally high activity, resulting in strongly increased cumene conversion and extraordinarily high selectivity to acetophenone and 2-benzyl-2-propanol. The incorporation of nitrogen altered the surface electron structure of the CNTs and tuned the reactivity and selectivity. DFT calculations revealed that the remarkable improvement of catalytic performance of NCNTs is caused by the strong interaction between hydroperoxide cumene and the NCNTs. NCNTs also exhibited desirable recyclability after four cycling tests. This study not only provides a novel method for the cumene oxidation to high-value-added products at moderate reaction temperatures and oxygen atmospheric pressure, but also gives new insights into the effect of surface nitrogen doping on carbon-catalyzed liquid-phase oxidation of aromatic hydrocarbons. [ABSTRACT FROM AUTHOR]

Abstract: Nitrogen doped anatase TiO2 (N-TiO2) were prepared by hydrothermally treating TiN with H2O2. The as-synthesized samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), UV–vis diffuse reflectance spectrum (DRS), Fourier transform infrared spectra (FT-IR) and X-ray photoelectron spectroscopy (XPS) techniques. The results confirmed that the hydrothermal oxidation is an effective method to prepare N-doped TiO2 anatase. The nitrogen concentration in TiO2 could be controlled by the concentration of H2O2 solution. Photocatalytic degradation of methyl orange (MO) was carried out under visible light and UV–visible light irradiation, respectively. The as-prepared optimal N-TiO2 showed higher photocatalytic activity than N-P25 and P25, and exhibited excellent reusability. [Copyright &y& Elsevier]

Abstract: Pt/CNTs, PtRu/CNTs, Pt/RuO2/CNTs and RuO2/Pt/CNTs were prepared to understand the role of RuO2 in anodic catalyst of direct methanol fuel cell (DMFC). The results show that the presence of Ru, no matter in alloy or in oxide, can improve the CO electrooxidation ability. RuO2 in Pt–Ru binary catalyst, which situates between CNTs and Pt particles, can exert its CO electrooxidation ability best. Another role of RuO2 in Pt–Ru binary catalyst is to promote Pt nanoparticles to disperse uniformly on CNTs to obtain larger EAS, resulting in higher activity of methanol electrocatalytic oxidation. [Copyright &y& Elsevier]

In this paper, a series of metallic chloride catalysts supported on activated carbon are prepared. The results show that NiCl2/C has a high conversion of methanol, and CuCl2/C has a high selectivity to methyl acetate for methanol vapor-phase carbonylation without addition of any promoter in the feed. The results show that NiCl2–CuCl2/C has a higher activity and selectivity of methanol carbonylation than NiCl2/C, and the yield of methyl acetate increased by 25%. The optimum component of composite catalyst is 5% NiCl2 and 15% CuCl2. This novel NiCl2–CuCl2/C catalyst has high activity and good stability for methanol vapor-phase carbonylation. The reaction conditions are optimized as follows: reaction temperature of 573 K, methanol concentration of 14.5 mol% and carbon monoxide space velocity of 3000 L/(kgcat h). Under the optimum conditions, methanol conversion of 34.5% and carbonylation selectivity of 94.7 mol% are obtained. Structures of catalysts are characterized with SEM-EDS and XRD. [Copyright &y& Elsevier]

The Cover Feature shows that compared to pure carbon, nitrogen doping retards the superoxide disproportionation in the oxygen reduction reaction in an alkaline medium, thereby promoting the energy conversion efficiency. More information can be found in the Communication by Li et al. on page 1133 in Issue 6, 2019 (DOI: 10.1002/cssc.201802601). [ABSTRACT FROM AUTHOR]

A high-efficiency and low-cost Zr-based metal–organic frameworks loaded with Co catalyst for the catalytic transfer hydrogenation of biomass-derived 5-hydroxymethylfurfural (HMF) into 2,5-dihydroxymethylfuran (DHMF) through Meerwein–Ponndorf–Verley reduction was developed. A series of Co/UiO-66-NH2 catalysts were synthesised by wet impregnation and reduction using the KBH4 method and characterized by XRD, ICP-OES, XPS, SEM, TEM, BET and TPD techniques. As expected, Co1.6/UiO-66-NH2 displayed high catalytic transfer hydrogenation activity with 92.6% HMF conversion and 95.9% DHMF selectivity at a relatively mild reaction temperature (100 °C) in the presence of isopropanol that served as both hydrogen donor and reaction solvent. The highly dispersed Co species may effectively regulate the acid–base sites of the catalyst, which could be the main reason for the high hydrogenation activity. [ABSTRACT FROM AUTHOR]

Abstract: Carbon nanotube immobilized IrO2 (IrO2/CNT) was prepared by a simple oxidation method with hydrogen peroxide as an oxidant and used as an improved catalyst support to load active Pt to prepare Pt/IrO2/CNT anode catalyst for direct methanol fuel cell. Electrochemical measurement revealed that Pt/IrO2/CNT exhibits much higher activity for methanol oxidation and better CO tolerance than Pt/CNT. The anodic peak current of methanol oxidation on Pt/IrO2/CNT (873.1A gPt −1) is 2.6 times that of Pt/CNT catalyst (335.7A gPt −1). The enhanced performance of Pt/IrO2/CNT is attributed to the fact that IrO2 improves the dispersion of Pt nanoparticles, and lowers the charge transfer resistance in methanol electrooxidation. [Copyright &y& Elsevier]

A Cu 2 O/(001)TiO 2 @Ti 3 C 2 T x photocatalyst was synthesized via a wet-chemistry reduction method by N, N-dimethylformamide (DMF). By scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD), it was revealed that the surface coverage of photocatalyst increased with the loading amount of Cu 2 O, while the particle size of Cu 2 O did not change significantly. The photocatalytic activity and mechanism of ternary Cu 2 O/(001)TiO 2 @Ti 3 C 2 T x photocatalyst heavily depend on the surface coverage of copper species. When the surface coverage of photocatalyst by Cu 2 O was low, the Ti 3 C 2 T x acted as hole reservoir. Cu 2 O was firstly reduced in situ to metallic copper by excited electrons. Then the reverse movement of carriers enabled the spatial separation of photogenerated electron-hole pairs, and afforded relatively high hydrogen evolution (more than 1100 μmol h−1 (g CuO x TiO 2)−1). When the coverage of Cu 2 O on (001)TiO 2 @Ti 3 C 2 T x was too high at high loading amounts, Ti 3 C 2 T x failed to play the role of hole trapping. Under that circumstance, the photocatalytic reaction follows p-n junction mechanism, leading to low hydrogen productivity. The results here shed light on the relationship between structure and activity of Cu 2 O/(001)TiO 2 @Ti 3 C 2 T x , which was conducive to the development of the MXene-based photocatalysts. Image 1 • A Cu 2 O–TiO 2 –Ti 3 C 2 T x ternary catalyst fabricated by a solvent reduction method. • The loading amount and surface coverage of Cu 2 O can be easily adjusted. • The hydrogen evolution activity can be manipulated by the amount of copper species. • The photocatalytic reaction mechanism depends on the surface coverage of Cu 2 O. [ABSTRACT FROM AUTHOR]

• Co N C single-atom catalysts effectively catalyze the aerobic oxidation of benzyl alcohol. • The oxidation reaction follows a dual-site Langmuir–Hinshelwood mechanism. • The competitive adsorption of benzyl alcohol and oxygen on cobalt leads to self-poisoning. • Polar solvents seriously deactivate Co N C single-atom catalysts. Me N C catalysts have received intensive scientific interest as non-noble-metal single-atom catalysts (SAC) for electrochemical- and thermocatalytic reactions. However, the lack of understanding of its properties hinders further improvement of the catalytic performance. An interesting issue is the molecular details of the reaction involving more than one reactant, since the activation of the second reactant is inevitably affected by the first one on SAC. Here, we synthesized Co N C SACs for the aerobic oxidation of benzyl alcohol (BA) to benzaldehyde. The catalyst exhibited excellent activity for this reaction, among the most active non-noble-metal catalysts. Differently from particulate metal or metal oxide catalysts, the Co N C SAC displayed "self-poisoning" due to the strong competitive adsorption of BA to O 2 , as revealed by kinetics experiments and density functional theory calculations. Moreover, we rationalized the poisoning effect of polar moieties, including organic solvents and aqueous solutions, on the SAC. These results shed light on the catalytic behavior of aerobic oxidation of BA on the molecular level and enable the rational design of catalytic organic synthesis over Co N C SACs. [ABSTRACT FROM AUTHOR]

Nitrogen-doped carbons can effectively stabilize noble metal particles to achieve high catalytic performances. However, the metallic impurities in carbon nanomaterials, e.g. the residual growth catalysts of carbon nanotubes (CNTs), have some unforeseen effects on the catalysis involving nanocarbons. Herein, we demonstrate that the residual growth catalysts of N-doped CNTs (NCNTs) may significantly deactivate Pd catalysts for the hydrogenation of nitrobenzene. Through high-resolution transmission electron microscopy and CO-stripping, it was determined that the N dopants improved the dispersion of Pd nanoparticles. However, the iron, at ppm level, in residual catalysts encapsulated inside NCNTs can transfer onto the surface of Pd to block active sites so that the activity of Pd/NCNTs was much lower than that of Pd/CNTs. The similar effect was observed for most of the common metallic impurities in carbon materials, including Co, Ni, Mn, Cr, Cu, Zn, Mo, Al and Mg. To exploit the N-doped carbons, we deposited N-doped carbon layers on purified CNTs through pyridine pyrolysis and then supported Pd nanoparticles. By this means, the activity of Pd for nitrobenzene hydrogenation was improved by 3.85 folds compared to conventional CNTs, emphasizing the importance of controlling impurities in N-doped carbon materials for high performance catalysts. [ABSTRACT FROM AUTHOR]

Photocatalytic intermediate water splitting (PIWS) provides a promising route for hydrogen production as its high product value, favorable kinetics and easy separation. However, the traditional oxide and sulfide-based catalysts either respond to ultraviolet light or suffer from severe photocorrosion and sluggish kinetics, leading to poor conversion efficiency. Herein, we employ a two-step photosynthesis strategy to prepare an inexpensive phosphorus (PO) protection layer and nickel phosphate (Ni 3 Pi 2) cocatalyst on the Zn 0.14 Cd 0.86 S (ZCS) photocatalyst, which shows a H 2 and H 2 O 2 evolution rate of 1.464 and 1.375 mmol h−1 g−1 in water splitting under 20 h visible light irradiation. The excellent PIWS performance originates from a combination of anti-photocorrosion ability of PO protection layer and bi-functional role of Ni 3 Pi 2 , which decompose into Ni 2 P and NiPi to enhance the H 2 and H 2 O 2 evolution. Moreover, the two-step photosynthesis process triggers photocatalytic partial water splitting (PPWS) by oxidizing NaH 2 PO 2 , with H 2 evolution rate of 9.26 and 9.53 mmol h−1 g−1, respectively. This work develops a photosynthesis assembling of ZCS/PO/Ni 3 Pi 2 catalyst, which not only presents superior performance for H 2 O 2 evolution but also achieves a high average H 2 production rate of 0.28 mmol h−1 under 25 h visible light irradiation by integrating the three-stage PPWS→PPWS→PIWS process. [Display omitted] • PO protection layer and Ni 3 Pi 2 cocatalyst are prepared by photosynthesis method. • The PPWS reaction is induced by the oxidation of NaH 2 PO 2 in above process. • The prepared ZCS/PO/Ni 3 Pi 2 sample exhibites efficient PIWS activity and stability. • Ni 2 P and NiPi cocatalysts are formed by Ni 3 Pi 2 species in-situ. • A three-stage "PPWS→PPWS→PIWS" photocatalytic H 2 evolution route is realized. [ABSTRACT FROM AUTHOR]

The electron-rich interface of Cu-Co heterostructure nanoparticle an realize the effective separation of photogenerated charge and hole, accelerate the transfer of photogenerated charges, which is a stable and efficient cocatalyst for photocatalytic hydrogen evolution reaction. [Display omitted] • Carbon-coated Cu-Co alloy nanoparticles (CuCo@C) nanoparticles are fabricated. • The bimetallic CuCo has a heterogeneous structure with abundant Cu-Co interfaces. • A large number of photogenerated electrons can be collected at the Cu-Co interface. • The CuCo@C is a high-performance cocatalyst for photocatalytic H 2 evolution. Heterogeneous nano-metal structures are widely used in the field of photocatalysis as an efficient cocatalyst, but the structure–activity relationship has not been elucidated clearly. In this work, a classical CuCo@C nanoparticle with a core of bimetallic CuCo and a carbon shell was used as a cocatalyst to explore and reveal the mechanism of interfacial effect for enhanced photocatalytic hydrogen evolution. It was found that the bimetallic CuCo had a heterogeneous structure with abundant Cu-Co interfaces. The desirable visible-light-driven photocatalytic hydrogen evolution rate of CuCo@C/g-C 3 N 4 was much higher than that of Cu@C/g-C 3 N 4 , Co@C/g-C 3 N 4 , and superior to that of the control group loaded with 1 wt% Pt (Pt/g-C 3 N 4). According to the experimental characterizations and density functional theory calculations, electrons were enriched at the Cu-Co interface, which can promote the electron-hole pairs separation and accelerate charge transfer of the g-C 3 N 4 host photocatalysts. On the other hand, the surface carbon layer and Cu-Co interface modulated the H adsorption free energy on the CuCo@C, which was favorable for hydrogen evolution. It is conceivable that further investigating and tuning different metal interfaces will facilitate the large-scale application of bimetallic cocatalysts. [ABSTRACT FROM AUTHOR]

Abstract: Cellulose, as an energy substance with tremendous resources, is reproducible and is a breakthrough point for the research of renewable energy. It is urgent and necessary to realize the conversion of cellulose with high efficiency under the mild condition. Ru immobilized on CNTs (Ru/CNTs) catalyst was prepared and used to the reaction of cellulose to polyols. The influence factors, such as the Ru loading amount, reaction time, reaction temperature and hydrogen pressure were investigated. The role that Ru/CNTs played in the reaction and the procedure of cellulose to polyols were discussed. The experimental results show that cellulose can be converted into C2-C6 polyols with the yield up to 38% catalyzed by Ru/CNTs with 4 wt% Ru loading and at the temperature of 225 °C and the hydrogen pressure of 6 MPa within the reaction time of 30 min. The conversion of cellulose to polyols catalyzed by Ru/CNTs is in fact a two-step reaction with cellulose first to reducing sugar and then to polyols. In the process of cellulose to polyols, CNTs promotes the cellulose to convert into reducing sugar by hydrolysis and Ru catalyzes the conversion of the reducing sugar to polyols by hydrogenation. [Copyright &y& Elsevier]

Using the cyclic voltammetry to test the performance of methanol electrooxidation is the most popular method to seek anodic catalysts for direct methanol fuel cells. A cyclic voltammetry of methanol electrooxidation typically has two peaks on Pt-based catalysts: one peak of P f with the current of j f in the forward scan, the other peak of P b with the current of j b in the backward scan. The ratio of j f / j b is an intensively used criterion to evaluate the ability of CO tolerance of Pt-based catalysts. In this study, however, it is demonstrated that both peak currents are ascribed to the consumption of methanol at the surface of the electrode using the differential electrochemical mass spectrometry (DEMS). In addition, our results reveal that the peak area ratio should be a criterion linking to the overlapping region between the potentials of methanol oxidation and the potentials of the reduction of the oxidized surface generated in the forward scan. Based on our analysis, the ratio of the integrated current of P f and P b can be a new descriptor to describe the reducibility of the oxidized Pt surface formed at high potential instead of CO anti-poisoning of the catalyst. [Display omitted] • Differential electrochemical mass spectrometry is used to monitor methanol oxidation. • The characteristic of cyclic voltammetry (CV) of methanol oxidation is revealed. • A new descriptor in evaluating the anti-oxidizing of catalyst is proposed. • The electrode surface changes during CV process are elucidated precisely. [ABSTRACT FROM AUTHOR]

• Phosphorus-doped Co 9 S 8 and carbon sphere composite (Co 9 S 8 /P@CS) is prepared. • Co 9 S 8 /P@CS performs a high electrocatalytic activity for oxygen evolution reaction. • A super-stable Zn-air battery is assembled with Co 9 S 8 /P@CS as air-electrode catalyst. • Co 9 S 8 /P@CS shows a power density of 142 mW cm−2 superior to Pt/C-IrO 2. • The relationships between structure and the catalytic performance is revealed. A novel phosphorus-doped Co 9 S 8 and carbon nanosphere composite (Co 9 S 8 /P@CS) was successfully prepared by adding a certain amount of sodium hypophosphite during the thermal treatment process of preparing Co 9 S 8. The results of XRD and XPS confirmed the incorporation of phosphorus into the lattice of Co 9 S 8. Electrochemical tests demonstrated that Co 9 S 8 /P@CS performs a high electrocatalytic activity for oxygen evolution reaction (OER). Under the current density of 10 mA cm−2, Co 9 S 8 /P@CS-1:2 as the best catalyst has the lowest overpotential of 233 mV and Tafel slope of 48 mV dec–1, which is far superior to the current noble-metal catalyst IrO 2 (414 mV, 96 mV dec–1). A rechargeable Zn-air battery was assembled with Co 9 S 8 /P@CS-1:2 as the air-electrode catalyst. Its maximum power density reached 142.50 mW cm−2 at 0.56 V and the current density was 255.47 mA cm−2, significantly higher than those of the battery made by Pt/C-IrO 2 catalysts. Especially, after 350 h (1050 cycles) of charge and discharge, the performance of this assembled battery did not show a significant decrease, predicting a broad application prospect. In-situ Fourier transform infrared spectroscopy (FTIR) and density functional theory (DFT) calculations were used to analyze the active sites of catalyst and catalytic mechanism, revealing the relationships between structure and the catalytic performance for OER. [ABSTRACT FROM AUTHOR]

• A feasible approach to catalyze xylose-rich hydrolysate into furfural was proposed. • A recyclable FePO 4 catalyst was applied as well as the modified biphasic system. • The water solubility and the catalysis mechanism of FePO 4 were studied. • 88.7% furfural yield and 96.6% selectivity were obtained from pre-hydrolysate. • The FePO 4 catalyst displayed good recyclability and stability in this system. Efficient conversion of dilute-oxalic acid pretreated bagasse hydrolysate to furfural was developed using recyclable ironic phosphates (FePO 4) catalysts in the modified heterogeneous system. The effects of reaction conditions on the furfural yields were investigated, and the stability and water solubility of catalysts were evaluated. Results showed that the maximum furfural yield of 88.7% was obtained in the modified biphasic system by FePO 4 catalysts at 190 °C for 120 min. The catalyst could be recycled and reused in conversion of the xylose-rich hydrolysate into furfural due to the unique feature that the catalyst showed solid state at room temperature and could be gradually dissolved into the aqueous phase upon increasing the reaction temperature and time. The experiments of five-time recycles showed that the FePO 4 catalyst exhibited excellent stability and catalytic performances. [ABSTRACT FROM AUTHOR]

Phosphorus-doped graphitic-C3N4 nanosheets coupled with BiPO4 nanorods are hydrothermally synthesized from aqueous solutions containing CH2N2, NaH2PO4, Bi(NO3)3, and HNO3 (autoclave, 483 K, 4 h), followed by calcination at 823 K for 4 h. [ABSTRACT FROM AUTHOR]