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Zr‐monosubstituted polyoxometalates (Zr‐POMs) of the Keggin (Bu4N)8[{PW11O39Zr(μ‐OH)}2] (Zr‐K), Lindqvist (Bu4N)6[{W5O18Zr(μ‐OH)}2] (Zr‐L), and Wells‐Dawson (Bu4N)11H3[{P2W17O61Zr(μ‐OH)}2] (Zr‐WD) structures are capable of heterolytic activation of the environmentally benign oxidant tert‐butyl hydroperoxide (TBHP) and catalyze epoxidation of alkenes and oxidation of alcohols to carbonyl compounds. Catalytic activity of corresponding Ti‐POMs is much lower. Among Zr‐POMs, Zr‐K revealed higher epoxide yields. All Zr‐POMs do not catalyze unproductive TBHP degradation, and epoxide yields with both aqueous and anhydrous TBHP are generally higher than with aqueous H2O2. Regioselectivity of the Zr‐K‐catalyzed limonene epoxidation with TBHP is different from that with H2O2: the more substituted and nucleophilic double bond is preferably epoxidized, pointing to an electrophilic oxygen transfer mechanism. The oxidation rates are first order in catalyst (Zr‐K) and substrate (cyclooctene or cyclohexanol) and show a saturation behavior with increasing concentration of TBHP. Studies by HR‐ESI‐MS, ATR‐FT‐IR, and 31P NMR spectroscopic techniques implicated the formation of zirconium alkylperoxo species upon interaction of Zr‐POMs with TBHP. HR‐ESI‐MS revealed the existence of monomeric and dimeric alkylperoxo complexes, [{PW11O39Zr}((CH3)3COO)]4− and [{PW11O39Zr((CH3)3COO)}2]8−, with predomination of the former, which is most likely the active species responsible for the selective oxidations. [ABSTRACT FROM AUTHOR]

Photocatalytic CO2 reduction coupled with alcohol oxidation to aldehyde presents a promising strategy for the simultaneous production of fuels and valuable chemicals. The efficiency of the coupled photocatalytic reactions remains low due to poor charge separation, difficulty in CO2 activation, and uncontrolled compatibility between reactions. This work presents S‐bridged covalent triazine framework (SCTF) core‐ZnIn2S4 shell photocatalysts for simultaneous CO2 reduction and selective furfural synthesis at distinct active sites. As evidenced by in situ X‐ray photoelectron spectroscopy and Kelvin probe force microscopy, photogenerated electrons in the composite photocatalysts transfer from the ZnIn2S4 shell to the SCTF core, improving charge separation. Experimental and theoretical results confirm that the presence of pyridine N atoms (Lewis basic sites) in SCTF enhances CO2 adsorption, thereby reducing the energy barrier for *COOH generation and promoting *CO production. Meanwhile, furfuryl alcohol oxidation and deprotonation occur on ZnIn2S4 by consuming photogenerated holes, which in turn benefits the conversion of CO2 to CO. As a result, the optimized SCTF/ZnIn2S4‐0.2 core/shell photocatalyst exhibited a superior CO production yield of 263.5 µmol g−1 and 95% conversion of furfuryl alcohol to aldehyde under simulated sunlight irradiation. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, a new mesoporous silica nanostructure functionalized with hydrobenzoin substituted cobalt (II) phthalocyanine (MCM‐41‐CoPc) was prepared by grafting first 3‐chloropropyltriethoxysilane (CPTES) and then peripherally hydrobenzoin substituted cobalt (II) phthalocyanine (CoPc) onto mesoporous silica nanomaterial (MCM‐41). The structural properties of heterogeneous catalyst MCM‐41‐CoPc were elucidated by FT‐IR, XRD, TEM, EDS, TGA, solid‐state UV–Vis and N2 sorption analyses. The catalytic performance of MCM‐41‐CoPc was investigated in the oxidation of benzyl alcohol to benzaldehyde. To find the best catalytic conditions for aldehyde selectivity, the effect of the different parameters such as temperature, reaction time, oxidant, solvent, amount of the substrate, and oxidant on the catalytic activity of MCM‐41‐CoPc was investigated in detail. The selective oxidation of benzyl alcohol to benzaldehyde in the presence of MCM‐41‐CoPc was achieved with high aldehyde selectivity (98%) and moderate conversion (57%). The reusability of MCM‐41‐CoPc was tested in three consecutive cycle and no catalytic activity loss was observed. Additionally, it has been determined that the product selectivity can be controlled depending on the type of reaction solvent. When ethyl acetate was used as the solvent, 98.5% conversion rate and 96% benzoic acid selectivity were obtained. [ABSTRACT FROM AUTHOR]

Nitroxide radicals are widely utilized as catalysts for the oxidation of primary alcohols. Here, the aerobic catalytic oxidation cycle of nitroxide radicals has been implemented within a mechanically interlocked rotaxane architecture consisting of a paramagnetic crown ether, which is confined by a molecular axle containing a dialkylammonium station and a 1,2,3-triazole unit. The rotaxane is engineered to exploit the oxidation of a primary alcohol: the primary catalyst is the wheel, a nitroxide radical capable of altering its oxidation state during the catalytic cycle, while the co-oxidant is the Cerium(IV)/O2 couple. The synthesis of the proposed rotaxane, along with its characterization using EPR, HRMS, voltammetry and NMR data, is reported in the paper. The aerobic catalytic oxidation cycle was further investigated using EPR, NMR and GC-MS analyses. This study can aid in the design of autonomously driven molecular machines that exploit the aerobic catalytic oxidation of nitroxide radicals. Catalytic cycles have been demonstrated in mechanically interlocked systems. Here, the authors report a [2]rotaxane containing a nitroxidic radical macrocycle and establish the efficiency of its catalytic redox cycle in this constrained environment. [ABSTRACT FROM AUTHOR]

The ternary chalcogenide ZnIn2S4 (ZIS) has been synthesized by a simple hydrothermal method in which the carcinogen thiacetamide, universally used as a precursor, has been, for the first time, replaced successfully with the harmless thiourea. ZIS has been used as photocatalyst for the partial oxidation of different aromatic alcohols to their corresponding aldehyde in water solution, under ambient conditions and simulated solar light irradiation. The photocatalytic performance of ZnIn2S4 was better than TiO2 P25. In the presence of ZIS for 4‐methoxybenzyl alcohol, piperonyl alcohol, and benzyl alcohol, a selectivity towards the corresponding aldehyde of 99 % for a conversion of 46 %, 75 % for a conversion of 81 %, and 87 % for a conversion of 25 %, respectively, was obtained. For the same alcohols a selectivity of 19 % for a conversion of 41 %, 19 % for a conversion of 13 %, and 16 % for a conversion of 26 %, was observed in the presence of TiO2 P25. [ABSTRACT FROM AUTHOR]

The rapid emergence of large language model (LLM) technology presents promising opportunities to facilitate the development of synthetic reactions. In this work, we leveraged the power of GPT-4 to build an LLM-based reaction development framework (LLM-RDF) to handle fundamental tasks involved throughout the chemical synthesis development. LLM-RDF comprises six specialized LLM-based agents, including Literature Scouter, Experiment Designer, Hardware Executor, Spectrum Analyzer, Separation Instructor, and Result Interpreter, which are pre-prompted to accomplish the designated tasks. A web application with LLM-RDF as the backend was built to allow chemist users to interact with automated experimental platforms and analyze results via natural language, thus, eliminating the need for coding skills and ensuring accessibility for all chemists. We demonstrated the capabilities of LLM-RDF in guiding the end-to-end synthesis development process for the copper/TEMPO catalyzed aerobic alcohol oxidation to aldehyde reaction, including literature search and information extraction, substrate scope and condition screening, reaction kinetics study, reaction condition optimization, reaction scale-up and product purification. Furthermore, LLM-RDF's broader applicability and versability was validated on various synthesis tasks of three distinct reactions (SNAr reaction, photoredox C-C cross-coupling reaction, and heterogeneous photoelectrochemical reaction). The rise of large language model (LLM) technology offers new opportunities for advancing chemical synthesis. Here, the authors developed an LLM-based reaction development framework (LLM-RDF) to copilot the design and experimental tasks throughout the end-to-end chemical synthesis development. [ABSTRACT FROM AUTHOR]

Organic electrochemical synthesis, a sustainable alternative to traditional organic synthesis, faces challenges in practical applications, such as limited current density, difficulty in recycling homogeneous electrochemical mediators, and large waste supporting electrolyte generation. In this work, we addressed these challenges by proposing a tandem electrochemical–chemical catalysis strategy, using selective alcohol electrooxidation to valuable aldehydes as a model transformation. Hypochlorite electro-generation and heterogeneous TEMPO-catalyzed alcohol oxidation were decoupled spatially, allowing each step to proceed independently under high rates and selectivity. Consequently, this strategy achieved industrially relevant current densities of 300–600 mA cm−2 with 64.7–81.8% faradaic efficiencies, resulting in a space–time yield (STY) of up to 516.95 kg (m3 h)−1 for benzaldehyde synthesis that significantly surpassed existing strategies. In addition, this strategy utilized the silica-supported TEMPO catalyst filled in a packed-bed reactor to achieve efficient single-pass conversion of alcohols to the corresponding aldehydes without the need for downstream catalyst separation, substantially reducing energy consumption for downstream separation. Furthermore, we developed a closed-loop tandem electrochemical–chemical catalysis system for gram-scale steroidal aldehyde synthesis, which incorporated an inline liquid–liquid separator for electrolyte recycling, thus significantly reducing the supporting electrolyte waste generation, which aligns with the principles of green chemistry and sustainable development. This work demonstrates a viable approach for the electrosynthesis of value-added organic intermediates under practical current densities with minimal waste electrolyte. [ABSTRACT FROM AUTHOR]

Classic in situ electro‐organic synthesis with substrates in an electrolyzer must compromise process conditions to balance electro‐ and thermochemical steps at both electrodes. This often restricts efficiency and product selectivity, since requirements may deviate for electrochemical (catalyst activation) and chemical (organic synthesis) steps, as well as for paired anode‐ and cathode reactions. Breaking this barrier, we report ex situ electro‐organic synthesis as a versatile method that enables unique product selectivity and unusual product pairs. We exemplify the concept for pairing H2 evolution (HER) with anodic alcohol oxidation. The two‐step method accomplishes this by separating cathode reactions from organic substrate oxidation, and anodic electrocatalyst activation from chemical conversion of organic substrates in time and space. First, the electro‐oxidation of Ni(OH)2 anodes to NiOOH is paired with H2 production by alkaline water electrolysis. Then, "charged" NiOOH electrodes are removed from the electrolyzer and used in external vessels to oxidize model substrate benzyl alcohol under regeneration of Ni(OH)2. Free choice of reaction media outside the electrolyzer allows to selectively obtain benzoic acid (in water) or benzaldehyde (in n‐hexane), whereas classic in situ electrosynthesis only produces the acid together with H2. Perspectively, the method enables electrosynthesis of previously inaccessible products paired to H2 generation. [ABSTRACT FROM AUTHOR]

ABSTRACT A thermo‐responsive ruthenium catalyst was produced by immobilizing poly(N‐isopropyl acrylamide) on the silica surface coated iron oxide nanoparticles (Fe3O4@Si). After being exposed to ethylenediamine, the amino‐modified support (Fe3O4@Si‐PNIPAM‐NH2) was produced, and Fe3O4@Si‐PNIPAM‐NH2‐EDTA was made in the ensuing reaction with EDTA (ethylenediaminetetraacetic acid). Ru NPs were introduced to the modified magnetic support to create a well‐organized heterogeneous catalytic system with several advantages, such as enabling catalyst recycling and simple separation. This new catalyst was characterized by means of various techniques, including TGA, ICP, FT‐IR, DLS, TEM, SEM, EDX, VSM, XRD, CHN, and XPS. In the presence of H2O2 or air alone, this catalyst showed a significant effect in the oxidation of various alcohols to the corresponding aldehydes or ketones. Furthermore, the catalyst exhibited outstanding capacity in the aerobic oxidation of olefines to the carbonyl or oxirane counterparts. A main aspect of this catalytic system is the reusability of the catalyst at least eight times in consecutive runs without causing any discernible loss of activity, structural change, or leaching. [ABSTRACT FROM AUTHOR]

Here, Er/Yb Co-doped CaMoO4 materials (ErxYbyCa1−x−yMoO4 NPs where x = 0, 0.01 and y = 0, 0.05, 0.10, 0.15, 0.20) were prepared by microwave-assisted method and its pure-tetragonal structure were confirmed by X-ray diffraction spectra (XRD), Rietveld-refinement and Raman-vibrational spectra. The transmission-electron microscopy (TEM) study indicates the formation of nearly spherical shaped nanomaterial with average size of ~ 15 nm. Additionally, absorption and emission properties were studied by UV–Visible–NIR and photoluminescence (PL) spectrometer. The UV–Visible–NIR spectra attribute absorption of Er3+ ion in visible region (380–700 nm) and absorption of Yb3+ ion in near-infrared region (700–1400 nm). Moreover, PL up-conversion spectra of the sample recorded under excitation wavelength 980 nm. The PL peaks were observed at 530, 544–552, and 656–670 nm. Prominent PL-intensity was observed for Er0.01Yb0.15Ca0.84MoO4 phosphor. Temperature dependent PL study reveals that present phosphor is robust phosphor for temperature sensor. In addition, Er3+/Yb3+ doped CaMoO4 nanomaterials exhibited excellent activity and selectivity in the aerial oxidation of benzoin over benzyl under oxidant-free reaction conditions. The synergistic effect Er3+/Yb3+ co-doing in CaMoO4 matrix was observed, where only CaMoO4 material found to be inactive towards above oxidation reaction. Moreover, the oxidation of primary benzyl-alcohols was furnished in presence of tertiary butyl hydroperoxideas oxidant. [ABSTRACT FROM AUTHOR]

In this study, we present the successful application of new and known stable 16‐electron ruthenium(II) pincer complexes POCOP, based on the naphthoresorcinate backbone, [Ru(X)(POCOP)(CO)] (X = H, Cl, Br, I, OCOCF3), in the catalytic alkylation of ketones and the coupling between amines and primary alcohols under mild conditions. These protocols demonstrated tolerance to a wide range of alcohols, ketones, and anilines, with reactions proceeding in high conversions and selectivity towards the hydrogenated ketones and the imines. The use of an excess of alcohol as the proton source facilitated the formation of the hydrogenated products. These results mark a significant advancement in the development of catalytic reactions with ruthenium POCOP pincer derivatives. [ABSTRACT FROM AUTHOR]

A simple, economical, and safe method for the synthesis of mesoionic 1,3-diaryltetrazolium derivatives bearing a para -substituted phenyl group at the 1- or 3-position via thiosemicarbazides was established. Such compounds were directly obtained from the corresponding para -substituted anilines instead of aryl isothiocyanates and arylhydrazines. The newly synthesized mesoionic compounds were successfully converted into the corresponding nitrosotetrazolium salts, which were utilized as catalysts for oxidation of an aliphatic alcohol and analyzed by cyclic voltammetry to determine the correlation between the catalytic efficiencies and redox potentials. The proposed method can be widely applied and is valuable for investigating the substituent effects in mesoionic and related compounds. [ABSTRACT FROM AUTHOR]

Deep eutectic solvent (DES) has been considered as a useful catalyst and reaction medium for various organic transformations. Herein, we report the catalytic application of novel deep eutectic solvent- based surfactant (DES surfactant) for the selective and fast oxidation of alcohols to aldehydes. The readily accessible DES surfactants (FeCl3/BHDC) was prepared using inexpensive ferric chloride (FeCl3) and benzyl hexadecyl dimethyl ammonium chloride in a simple manner. The synthesized FeCl3/BHDC was characterized using various techniques, including, FTIR spectroscopy, thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), and energy- dispersive X-ray spectroscopy (EDS) to determine its structure. The catalytic activity of FeCl3/BHDC in the selective oxidation of various alcohols to corresponding aldehyde derivative was investigated. The results showed the reaction could be completed within very short reaction times ranging from 2 to 15 min, while achieving good to excellent yields. This protocol offers a facile strategy and excellent efficiency in selectively oxidizing various alcohol derivatives to their respective aldehydes and ketones, utilizing hydrogen peroxide in the presence of catalytic DES surfactant. [ABSTRACT FROM AUTHOR]

The research and development of new reagents play a crucial role for organic synthesis. In recent years, numerous new reagents with universal applicability have been reported. Recent research progress of selected fluorine-containing and sulfur-containing new reagents for difluoromethylation, trifluoromethylation and thiotrifluoromethylation are summarized. Additionally, some sulfur-containing new reagents are provided, as sulfur-containing reagent, Na2S2O4-t-butylhydroperoxide (TBHP) is a new reagent for selective oxidation of aromatic alcohols to aldehydes. [ABSTRACT FROM AUTHOR]

The phosphinito–phosphinous acid ligand (PAP) is a singular bidentate-like self-assembled ligand exhibiting dissymmetric but interchangeable electronic properties. This unusual structure has been used for the generation of active palladium hydride through alcohol oxidation. In this paper, we report the first theoretical highlight of the adaptative modulation ability of this ligand within a direct H-abstraction path for Pd and Pt catalyzed alcohol oxidation. A reaction forces study revealed rearrangements in the ligand self-assembling system triggered by a simple proton shift to promote the metal hydride generation via concerted six-center mechanism. We unveil here the peculiar behavior of the phosphinito–phosphinous acid ligand in this catalysis. [ABSTRACT FROM AUTHOR]

The selective oxidation of hydrocarbons can be used to produce oxygen-containing functional compounds such as alcohols, aldehydes or ketones and its efficient and green conversion lies in the development of efficient catalysts that activate C-H bonds and O2 simultaneously. In this work, the bimetallic organic framework (CoMnBDC) material with morphology of stacked nanosheets was synthesized using terephthalic acid as ligands to coordinate with Co2+ and Mn2+ cations under solvothermal conditions. As revealed by spectroscopic characterizations, the electron transfer from Mn to Co in the CoMnBDC resulted in the reduction of the Co average oxidation state and increase of the Mn average oxidation state. The CoMnBDC nanosheets were used as catalyst in catalytic oxidation of ethylbenzene, in which the redox effect promotes the effective electron transfer, the activation of O2 and benzyl C-H bond. The 96.2% conversion of ethylbenzene and 98.0% selectivity towards acetophenone could be obtained with oxygen as sole oxidant and solvent-free condition. The excellent catalytic performance is related to the structure of CoMnBDC and is also the best when compared with reported results. Various types of aromatic hydrocarbons containing benzyl C-H bonds can be effectively oxidized by CoMnBDC to produce corresponding ketone products. The density functional theory (DFT) calculation revealed that the redox effect leads to the relative enrichment of electrons on Co in CoMnBDC, which is conducive to the activation of O2; Mn with higher oxidation state is beneficial for the adsorption of ethylbenzene and activation of C-H bonds. The CoMnBDC has a lower energy barrier for transition state, making it easier for the ethylbenzene oxidation to produce acetophenone. [ABSTRACT FROM AUTHOR]

In this study, in-situ modification by TEMPO oxidation was performed after nanocomposite synthesis to improve its properties toward dye molecule removal. The unoxidized and oxidized polymeric-based nanocomposite was denoted as PNC6 and PNC6O respectively. The nanocomposites were characterized using FESEM, FTIR, contact angle, XRD and BET analysis. Measurements of swelling ratio and chemical stability were also performed to provide insight into the durability of the nanocomposites. The effects of changing variables included contact duration, pH of aqueous solution, initial pollutant concentration, and temperature were observed. The kinetic study showed that the experimental data is best fitted with pseudo-second-order kinetics (R2 = 0.988 and 0.997 respectively), whereas on observing isotherm data, in both unoxidized and oxidized nanocomposite it fits well with Langmuir isotherm (R2 = 0.951 and 0.993 respectively). In addition, the effects on Gibb's free energy, Enthalpy, and Entropy were measured in terms of thermodynamic characteristics, it was established that dye molecules adsorption mechanism is endothermic and spontaneous in behaviour. To check regeneration tendency of the nanocomposite seven consecutive adsorption desorption cycles were run and about 90% and 80%, regeneration ability could be seen in an unoxidized state (PNC6) and an oxidized state (PNC6O) respectively upto 5th cycle after that the tendency get reduced. This study suggests that this novel polymeric nanocomposite can be employed as an efficient and relatively inexpensive adsorbent for dye removal from aqueous solutions. [ABSTRACT FROM AUTHOR]

Water microdroplets have been demonstrated to exhibit extraordinary chemical behaviors, including the abilities to accelerate chemical reactions by several orders of magnitude and to trigger reactions that cannot occur in bulk water. One of the most striking examples is the spontaneous generation of hydroxyl radical from hydroxide ions. Alcohols and alkoxide ions, being structurally similar to water and hydroxide ions, might exhibit similar behavior on microdroplets. Here, we report the spontaneous generation of alkoxide radicals from alcohols (RCH2OH) in aqueous microdroplets through quantum chemical calculations, quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulations, ab initio MD simulations, and mass spectrometry. Our results show that an electric field (EF) on the order of 10−1 V/Å and partial solvation at the air‐water interface jointly promote the dissociation of RCH2OH into RCH2O− and H3O+ ions. QM/MM MD simulations indicate that RCH2O− can be ionized to produce RCH2O⋅ radicals on the microdroplet surface. Furthermore, partial solvation and the EF collaboratively catalyze the isomerization of the RCH2O⋅ radical into a more stable tautomer, R⋅CHOH. This study highlights the molecular mechanisms underlying the widespread generation of radicals at the microdroplet surface and provides insights into the importance of fundamental alcohol chemistry in the atmosphere. [ABSTRACT FROM AUTHOR]

Hydrothermally derived nanocubes of CeO2 (10 nm) were explored as an efficient heterogeneous catalyst in the partial oxidation of aromatic alcohols to the corresponding aldehydes and aerobic oxidation of p -nitrotoluene to p -nitrobenzoic acid. The CeO2 nanocatalyst was characterized by x-ray diffraction, transmission electron microscopy (TEM), energy dispersive spectroscopy, x-ray photoelectron spectroscopy, Brunauer–Emmett–Teller (BET) surface area analysis, Fourier transform infrared spectroscopy, thermal gravimetric analysis and ultraviolet–visible spectroscopy. TEM/high-resolution TEM micrographs reveal a morphology of mostly cubic nanostructures with exposed highly active {100} and {110} facets. The surface area of nanoceria was determined by BET analysis and found to be 33.8 m2 g−1. To demonstrate the universality of the catalytic system, the selective oxidation of different substrates of benzylic alcohol and complete oxidation of p -nitrotoluene was investigated under mild conditions. Absolute selectivity towards their respective aldehydes was found to be 99.50% (benzaldehyde), 90.18% (p -chlorobenzaldehyde), 99.71% (p -nitrobenzaldehyde), 98.10% (p -fluorobenzaldehyde), 94.66% (p -anisaldehyde) and 86.14% (cinnamaldehyde). Moreover, the catalytic oxidative transformation of nitrotoluene results in 100% conversion with 99.29% selectivity towards nitrobenzoic acid. [ABSTRACT FROM AUTHOR]

To optimize the performance of photocatalytic H 2 production, many effective methods have been developed, such as controlling morphology, designing synergetic reaction, and enhancing the utilization of photogenerated charge carriers (PCCs). In this work, an efficient CoMoO 4 /Zn 0.3 Cd 0.7 S (CMO/ZCS) photocatalyst with p-n heterojunction was constructed by incorporating Zn 0.3 Cd 0.7 S (ZCS) nanoparticles into CoMoO 4 (CMO) microflowers. Although CMO had limited activity in H 2 production under visible light irradiation, it could largely boosting the H 2 production efficiency of ZCS nanoparticles by oxidizing p-chlorobenzyl alcohol (Cl-PhCH 2 OH) in organic solvent. In the CMO/ZCS composites, the best rates of H 2 and Cl-PhCHO reached 34.28 and 35.87 mmol g−1 h−1, respectively. The p-n heterojunction formed between CMO and ZCS may be the main enhanced reason of the excellent performance, as it could effectively improve the separation, transfer and utilization of PCCs. The design of the CMO/ZCS catalyst not only optimizes the migration and utilization of PCCs, but also provides crucial theoretical guidance and experimental insights for the development of highly efficient photocatalysts. [Display omitted] • CoMoO 4 /Zn 0.3 Cd 0.7 S heterojunction was prepared by self-assembly method. • Zn 0.3 Cd 0.7 S nanoparticles are incorporated into CoMoO 4 microflowers. • p-n heterojunction improves the transfer of photogenerated charge carriers. • Photocatalytic H 2 evolution is promoted by 4-chlorobenzyl alcohol oxidation. [ABSTRACT FROM AUTHOR]

A promising CeO2‐Co3O4 (9 : 1 mole ratio based on oxides) non‐noble metal based mixed oxide catalyst was explored for selective oxidation of vanillyl alcohol with molecular oxygen to produce vanillin under atmosphere pressure. In particular, to enhance its efficiency, this catalyst was prepared by adopting different preparation methods namely, template assisted, coprecipitation with and without surfactant, wet‐impregnation, and solution combustion. The prepared catalysts were characterized by XRD, Raman, BET surface area, ICP‐OES, FE‐SEM, HR‐TEM, H2‐TPR, and XPS. Among various catalysts investigated, the template assisted synthesized catalyst exhibited superior activity (100 % conversion and selectivity) and high stability. The better activity of this catalyst was found to be due to reduced crystallite size, high specific surface area (92 m2/g), more surface oxygen, and improved redox behaviour as confirmed from XRD, BET surface area, XPS, and H2‐TPR analysis, respectively. The stability of the catalyst was tested by reusability test and was observed that there is not much decrease in the catalytic activity up to five cycles. Further, the catalytic activity was optimized by varying the reaction parameters such as time, solvent, temperature, and catalyst weight. [ABSTRACT FROM AUTHOR]

ABSTRACT The rational design of noble metal‐free electrocatalysts represents one of the basic stones for fuel cell development. With the exploration of eco‐friendly nanomaterials for the investigated alcohol oxidation process, nickel‐based electrodes have been recognized as the most auspicious anodes with promoted activity and stability. In this work, a series of NiCo2O4 nanoparticles were deposited onto graphite sheets (NiCo2O4/T) introducing varied proportions of cobalt oxide species. Co‐precipitation protocol of the respective metallic hydroxides onto the carbonaceous support was followed with consecutive annealing in an air atmosphere at 400°C. The fabricated mixed metallic oxide nanopowder was physically studied using X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X‐ray analysis (EDX), X‐ray photoelectron spectroscopy (XPS), and selected area electron diffraction (SAED). Uniformly arranged nanoparticles were observed on graphite surface as evidenced by SEM and TEM. The cubic lattice structure of formed NiCo2O4 crystals was also confirmed by XRD through the defined peaks of binary metallic oxides clarifying their successful preparation scheme. The electrocatalytic properties of these NiCo2O4/T nanocatalysts were evaluated for oxidizing ethanol molecules in basic solution. Pronounced oxidation current densities were remarkably measured at NiCo2O4/T electrodes in relation to that at NiO/T. Differing the introduced cobalt oxide content into the synthesized nanocatalyst significantly controlled its catalytic performance. NiCo2O4/T‐20 exhibited the highest activity and stability among the prepared nanomaterials. Much decreased charge transfer resistances were also recorded at this electrode demonstrating its promoted electron transfer characteristics. This work could provide a reasonable route for the simple synthesis of comparable transition metallic oxides with promising attitudes for energy generation purposes. [ABSTRACT FROM AUTHOR]

[Display omitted] Solar-light driven oxidation of benzylic alcohols over photocatalysts endows significant prospects in value-added organics evolution owing to its facile, inexpensive and sustainable process. However, the unsatisfactory performance of actual photocatalysts due to the inefficient charge separation, low photoredox potential and sluggish surface reaction impedes the practical application of this process. Herein, we developed an innovative Z-Scheme Cs 3 BiBr 9 nanoparticles@porous C 3 N 4 tubes (CBB-NP@P-tube-CN) heterojunction photocatalyst for highly selective benzyl alcohol oxidation. Such composite combining increased photo-oxidation potential, Z-Scheme charge migration route as well as the structural advantages of porous tubular C 3 N 4 ensures the accelerated mass and ions diffusion kinetics, the fast photoinduced carriers dissociation and sufficient photoredox potentials. The CBB-NP@P-tube-CN photocatalyst demonstrates an exceptional performance for selective photo-oxidation of benzylic alcohol into benzaldehyde with 19, 14 and 3 times higher benzylic alcohols conversion rate than those of C 3 N 4 nanotubes, Cs 3 Bi 2 Br 9 and Cs 3 Bi 2 Br 9 @bulk C 3 N 4 photocatalysts, respectively. This work offers a sustainable photocatalytic system based on lead-free halide perovskite toward large scale solar-light driven value-added chemicals production. [ABSTRACT FROM AUTHOR]

As one of the most important synthetic fine chemicals and pharmaceuticals, benzaldehyde is widely used in pharmaceuticals, dyestuffs, fragrances and pesticides. It is still a difficult challenge to promote the conversion of benzyl alcohol to benzaldehyde by photocatalysis with high selectivity and high conversion. In this paper, the content of the reactive substance ·O2− is regulated by constructing suitable oxygen vacancies in TiO2 nanotubes, thus improving the photocatalytic conversion and selectivity. Herein, we have prepared TiO2-X 1D nanotubes enriched with different concentrations of oxygen vacancies by template method, hydrolysis of tetrabutyl titanate and vacuum annealing. By constructing suitable concentrations of oxygen vacancies in the TiO2 material, we can increase its ability to adsorb oxygen to produce more ·O2− on the one hand, and help to construct defective energy levels to prevent the compounding of photogenerated charge carriers to enhance photocatalytic activity on the other. As a result, the best photocatalytic activity of TiO2-X nanotubes obtained by vacuum annealing at 300 °C was 78% for benzyl alcohol conversion and 88% for benzaldehyde production selectivity, which is 2.6 and 1.8 folds higher than that of pristine TiO2 nanoparticles. Our work may provide insights for designing efficient photocatalysts for selective oxidation of benzyl alcohols. [ABSTRACT FROM AUTHOR]

Heterogeneous palladium‐based catalysts show excellent catalytic properties for electrocatalytic oxidation of alcohols, but the construction of such heterogeneous catalysts is a challenge. Here, a multiphase tetrahedral PdInMo nanocatalyst is prepared by a one‐pot reaction method. And the multiphase tetrahedral PdInMo nanocatalyst consists of a face‐centered cubic structure and an intermetallic structure. Due to the oxygen affinity of indium and molybdenum atoms, the interface defects of internal multiphase structure, and intermetallic structure, the multiphase concave tetrahedral PdInMo nanocatalyst shows enhanced catalytic efficiency in the electrocatalytic oxidation reaction of methanol and ethanol. Compared with commercial Pd/C catalysts, PdIn0.117Mo0.037 nanocatalyst has the best mass activity and specific activity. In electrocatalysis of methanol oxidation, the mass activity (2205.57 mA mgPd−1) and specific activity (6.67 mA cm−2) are 4.81 and 3.40 times than that of a commercial Pd/C nanocatalyst (458.5 mA mgPd−1, 1.96 mA cm−2), respectively. In the electrocatalysis of ethanol oxidation, the mass activity (2668.49 mA mgPd−1) and specific activity (8.11 mA cm−2) are 4.06 and 3.14 times than that of the commercial Pd/C nanocatalyst (655.83 mA mgPd−1, 2.58 mA cm−2), respectively. This study provides a reference for the design of highly efficient palladium catalysts for alcohol oxidation. [ABSTRACT FROM AUTHOR]

Replacing the slow protonation process of oxygen evolution reaction (OER) with the fast protonation of alcohol electro‐oxidation can decrease the driving potentials, thus improving overall efficiency of electrochemical devices. However, the formation of effective catalytic sites for alcohol oxidation remains challenging in accelerating protonation to inhibit metal leaching and improve catalyst stability. Herein, asymmetric Ni‐O‐Cr sites are constructed by alloying Cr into the NiO matrix to optimize coordination environments, showing significantly enhanced stability during alcohol electro‐oxidation. The asymmetric Ni‐O‐Cr can maintain constant valence states of Cr and Ni during alcohol oxidation, efficiently suppressing metal dissolution even at high oxidation potentials. In situ electrochemical characterizations combined with theoretical calculations indicate that asymmetric Ni‐O‐Cr can improve adsorption and activation of OH* and alcohol molecules compared to pure NiO, thus increasing anodic kinetics. The theoretical results also indicate that the smaller gap of Ni 3d‐O 2p in asymmetric Ni‐O‐Cr strengthens charge transfer, leading to fast protonation of catalytic sites with enhanced stability. This work gives insights into boosting anodic protonation using asymmetric sites‐enriched solid‐solution electrocatalysts. [ABSTRACT FROM AUTHOR]

Au single atoms and clusters were stabilized on Mg−Al layered double hydroxide nanoparticles (LDH NPs), and the obtained Au@LDH NPs were supported on SiO2 and CeO2. After hydrogen reduction, Au single atoms were found together with Au clusters on LDH/SiO2. In contrast to Au single‐atom catalysts which are deposited in metal vacancies of oxide supports, the LDH NPs stabilize very small Au species despite the absence of metal vacancies. The obtained Au(0)@LDH/SiO2 catalyzed aerobic oxidation of alcohols, and Au single atoms maintained after the reaction. Given that only Au NPs were observed on bulk LDH, the abundant surface OH group of LDH NPs would contribute to stabilize Au, resulting in higher activity than Au/LDH‐bulk. After calcination to transform LDH to mixed metal oxide (MMO), the obtained Au(0)@MMO/SiO2 also exhibited high catalytic activity. Moreover, Au(0)@LDH/CeO2 exhibited higher activity and excellent selectivity for hydrogenation of 4‐nitrostyrene to 4‐aminostyrene than conventional Au catalysts such as Au/CeO2 and Au/TiO2. We demonstrated that Au size can be minimized using LDH NPs, exhibiting high catalytic performance. The basic surface OH groups of LDH would be also beneficial for deprotonation of alcohols and heterolytic dissociation of H2 in the catalytic reactions. [ABSTRACT FROM AUTHOR]

In this work, melem‐based supramolecular assemblies were obtained in one step by thermal treatment of melamine in an autoclave in the presence of sodium chloride. The detailed analysis showed that the obtained powder consists of two phases: poorly crystalline Na‐PHI flakes and rod‐shaped melem hydrate single crystals (several micrometers long and ~300–500 nm wide). Melem hydrate crystals absorb light in the visible range (Eg=2.7 eV) and demonstrate photocatalytic activity in the reaction of partial oxidation of benzyl alcohol to benzaldehyde by air under visible light with high selectivity for the target product. At 60 % conversion of benzyl alcohol, the selectivity of benzaldehyde formation is above 95 %. [ABSTRACT FROM AUTHOR]

2D materials, such as graphene, MXenes (metal carbides and nitrides), graphdiyne (GDY), layered double hydroxides, and black phosphorus, are widely used as electrocatalyst supports for alcohol oxidation reactions (AORs) owing to their large surface area and unique 2D charge transport channels. Furthermore, the development of highly efficient electrocatalysts for AORs via tuning the structure of 2D support materials has recently become a hot area. This article provides a critical review on modification strategies to develop 2D material‐based electrocatalysts for AOR. First, the principles and influencing factors of electrocatalytic oxidation of alcohols (such as methanol and ethanol) are introduced. Second, surface molecular functionalization, heteroatom doping, and composite hybridization are deeply discussed as the modification strategies to improve 2D material catalyst supports for AORs. Finally, the challenges and perspectives of 2D material‐based electrocatalysts for AORs are outlined. This review will promote further efforts in the development of electrocatalysts for AORs. [ABSTRACT FROM AUTHOR]

ABSTRACT A copper‐based one‐dimensional framework compound [Cu2(L1)4(L2)]n (1) [L1 = 3‐(2‐thienyl)acrylic acid, L2 = 4,4′‐bipyridine] has been synthesized by slow diffusion of layers technique and characterized by spectroscopic methods and single‐crystal X‐ray crystallography. X‐ray diffraction analysis reveals that the compound is crystallized in the triclinic crystal system with space group Pī. Two neighboring Cu centers are bridged by four carboxylato groups from four different L1 ligands, leading to the formation of a paddle‐wheel [Cu2(COO−)4] secondary building unit (SBU). The paddle‐wheel units are interconnected by bidentate 4,4′‐bipyridine ligands to form a one‐dimensional infinite chain network. In [Cu2(L1)4(L2)]n (1), Cu(II) ion features a penta‐coordinated environment around it. Notably, [Cu2(L1)4(L2)]n (1) is capable of activating molecular oxygen to efficiently catalyze the oxidation of alcohols under base‐free conditions. [ABSTRACT FROM AUTHOR]

Replacing the sluggish oxygen evolution reaction with the oxidation of benzyl alcohol to construct the hybrid water electrolysis system has been attractive for its merits of environmentally friendly and economically efficient. However, the activity of the catalyst to oxidize alcohols needs to be further improved. Tailoring the d-band center (E d) has been proven as an effective method to promote the hydrogen evolution reaction (HER). How feasible is this strategy in the oxidation of benzyl alcohol? Here, using Co 2 C as a research platform, the doping nonmetal heteroatom (P, S, N) engineering is adopted to promote its electrocatalytic BA oxidation and HER performance. The results of electrochemical tests show that the P-doped Co 2 C (P–Co 2 C) only requires a low potential of 1.33 and 1.38 V vs. RHE to achieve current densities of 20 and 100 mA cm−2 for BA oxidation, which is superior to that of S–Co 2 C, N–Co 2 C, and pristine Co 2 C. The conversation and faradaic efficiency for BA is up to 98.1% and 93.8% during ten consecutive cycle tests. The P–Co 2 C also exhibited outstanding activity and stability toward HER. The density functional theory (DFT) calculation revealed that specified P doping could modify the d-band center of Co 2 C approaching the peak of the volcano map (electrochemical overpotentials ∼ E d). The Gibbs free energy of the BA oxidation was also reduced, thus optimizing the adsorption and desorption process of intermediates. On the other hand, the catalyst surface physical properties of Co 2 C such as hydrophilicity was promoted by the doped heteroatoms which was favorable for the gas-liquid-solid triphase electrocatalytic reaction. This work offers a facial perception of regulating the d-band to design advanced bifunctional electrocatalysts for organic matter oxidation and HER. The d-band center engineering was employed to boost the bifunctional electrocatalytic performance of X–Co 2 C (X = P, S, N). [Display omitted] • The X-doped Co 2 C (X = P, S, N) electrocatalysts were designed for BA oxidation and HER. • Among the prepared samples, the P–Co 2 C exhibited superior hydrophilicity and catalytic performance. • The P doping could change the d-band center of Co 2 C and optimize the adsorption/desorption process of intermediates. • The Gibbs free energy derived from the DFT was consistent with the order of electrochemical activity. [ABSTRACT FROM AUTHOR]

In this study, a Mn-Cr catalysts supported on self-synthesized SBA-15 for the oxidation of substituted benzyl alcohols using oxygen as the oxidant had been investigated. The mesoporous nature of SBA-15, characterized by its high specific surface area and regular pore structure, makes it an ideal carrier for catalysts with catalytic properties. Through careful optimization, an efficient Mn-Cr/SBA-15 catalyst had been developed, achieving a benzyl alcohol conversion rate of nearly 90% with a selectivity exceeding 98% towards benzaldehyde and its derivatives. Furthermore, the supported Mn-Cr catalysts exhibited remarkable stability, allowing for their reuse for at least five cycles without significant loss of activity or selectivity. These findings highlight the potential of Mn-Cr/SBA-15 catalysts as sustainable and effective options for the oxidation of substituted benzyl alcohols. The study contributes to the development of greener and more efficient oxidation processes in organic synthesis. A Mn-Cr/SBA-15 catalyst achieved an impressive conversion rate of nearly 90% for benzyl alcohol, with a selectivity exceeding 98% towards benzaldehyde. [ABSTRACT FROM AUTHOR]

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In this study, a sulfur–phosphorus co‐doped nanocarbon (SPC) catalyst was synthesized using a straightforward one‐step colloidal carbonization method and demonstrated high performance in the metal‐free direct oxidation of alcohols to aldehydes. This metal‐free SPC catalyst showed exceptional efficiency, achieving a conversion rate of 90% for benzyl alcohol and a selectivity of 94% toward benzaldehyde within only 1 h at 130°C. Moreover, it displays exceptional cycle stability and a high turnover frequency (17.1 × 10−3 mol g−1 h−1). Theoretical analysis suggested that the catalyst's superior performance is attributed to the presence of unsaturated edge defects and S−P− moieties, which increase the density of states at the Fermi level, lower the band gap energy, and promote electron localization. Additionally, the doping introduces cooperative co‐active S−P−C sites, facilitating a synergistic multisite catalytic effect that lowers the energy barriers. These findings represent a significant advancement in the field of metal‐free direct alcohol oxidation. [ABSTRACT FROM AUTHOR]

Theoretical modeling of the solid‐state photocatalysis is one of the important issues as various useful photocatalysts have been developed to date. In this work, we investigated the mechanism of the alcohol photooxidation on niobium oxide (Nb2O5) which was experimentally developed, using the density functional theory (DFT)/time‐dependent (TD)DFT calculations based on the cluster model. The alcohol adsorption and the first hydrogen transfer from hydroxy group to surface occur in the ground state, while the second hydrogen transfer from CH proceeds in the excited states during the photoirradiation of UV or visible light. The spin crossing was identified and the low‐lying triplet states were solved for the reaction pathway. The photoabsorption in the visible light region was characterized as the charge transfer transition from O 2p of alcohol to Nb 4d of the Nb2O5 surface. The spin density and the natural population analysis indicated the generation of spin density in the moiety of carbonyl compound and its dissipation to the interface of the surface, which partly explains the electron paramagnetic resonance measurement. It was confirmed that the rate determining step is the desorption of carbonyl compound and water molecule in agreement with the experimental rate equation analysis. The present findings with the theoretical modeling will provide useful information for the further studies of the solid‐state photocatalysis. [ABSTRACT FROM AUTHOR]

This review is focused on various reports in recent years on catalytic Wittig reactions and Knoevenagel condensation reactions in the presence of heterogeneous catalyst. The one-pot, cost-effective stereoselective catalytic Wittig reaction, is the reaction countering components generated by oxidation of primary alcohols without addition of base. Some reactions were reportedly performed under mild conditions, green and efficient approach providing the corresponding products in good to excellent yields within short times. The catalytic behavior over various catalysts for the Tandem oxidation reactions (TORs) was also summarized in this review. [ABSTRACT FROM AUTHOR]

Two oxidovanadium(IV) complexes [VO(xbp‐sc)] (1) and [VO(xbp‐tc)] (2) were prepared using hydrazine‐ether mixed functionality ligands Hxbp‐sc (I) and Hxbp‐tc (II), respectively. Complexes 1 and 2 were carefully grafted separately into imidazole‐modified chloromethylated polystyrene (Ps−Im) and unmodified chloromethylated polystyrene (PS−Cl) beads. Successfully anchored vanadium complexes Ps−Im‐[VO(xbp‐sc)] (3), Ps−Im‐[VO(xbp‐tc)] (4), Ps‐[VO(xbp‐sc)] (5), and Ps‐[VO(xbp‐tc)] (6) were tested for their catalytic potential towards the oxidation of aliphatic alcohols in the presence of hydrogen peroxide. Polymer‐grafted catalysts display excellent substrate conversion compared to most recent reports and good recyclability up to three cycles without losing much reactivity. High TOF values in the range of 183–591 h−1 are observed for the supported catalysts 3–6. The highest substrate conversion is observed for ethanol (63–97 %) under the optimized reaction conditions. Mainly, better substrate conversion is obtained with imidazole‐modified polymer beads grafted catalysts 3 and 4 than those grafted on unmodified polymer beads (5 and 6). Moreover, catalysts with the semicarbazide group in their ligand framework (3 and 5) show better reactivity towards alcohol with fewer carbon atoms. On the contrary, alcohols with longer carbon chains oxidize more easily in the presence of the catalyst with thiosemicarbazide frameworks (4 and 6). [ABSTRACT FROM AUTHOR]

High entropy materials (HEMs) compositing of at least five elements have gained widespread attention in the field of electrocatalysis due to their tunable activities and high stability. These intrinsic properties can be further highlighted when the size of HEMs comes to the nanoscale. In nanostructured HEMs, the fascinating properties including large composition space, multi‐element synergy, and high configuration entropy are expected to endow nano‐HEMs with excellent catalytic activity and stability, thus providing greater potential for the design of advanced electrocatalysts. In this review, nano‐HEMs are differentiated in detail in dimensions and the common synthesis methods are summarized. Additionally, from the perspective of the complex nanostructure‐performance relationship, the applications of nano‐HEMs in electrocatalysis systems, including water‐splitting (hydrogen evolution reaction (HER), oxygen evolution reaction (OER)), hydrogen oxidation reaction (HOR), oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR), nitrogen reduction reaction (NRR) and alcohol oxidation reaction (AOR) are discussed. Finally, the main challenges faced by nano‐HEMs electrocatalysis are underscored. This review is expected to provide more insights into understanding and developing efficient electrocatalytic materials for practical applications. [ABSTRACT FROM AUTHOR]

By the reaction of the binuclear cobalt-containing polyoxovanadate [Co2(H2O)2V10O30]6− with methanol, a tridecanuclear cobalt containing polyoxovanadate, [Co13(OH)6(OCH3)6V24O72]10− (Co13), was synthesized. Single crystals suitable for X-ray crystallographic analysis were obtained as trimethylphenylammonium salts. The tridecanuclear cobalt core exhibited a planar disk structure and 24 vertex-sharing VO4 units surrounded the edge of the disk. This is the largest VO4-based polyoxovanadate as far as we know. Compound Co13 was stable in the solution state. Electrochemical analysis showed the possibility of Co13 to act as an oxidation catalyst for alcohols. Compound Co13 acted as a catalyst for oxidation of several alcohols. After the reaction, the Co13 catalyst was retrieved by the addition of an excess amount of ethyl acetate and filtration. The structure of the catalyst was maintained and reused. The oxidation of not only aromatic but also aliphatic alcohols proceeded with Co13. Compound Co13 showed catalytic performance for the oxidation of secondary alcohols even in the presence of alkenic and primary alcoholic functions. [ABSTRACT FROM AUTHOR]

The hydrogenation of nitrogen‐containing heterocyclic precursors in aqueous medium is challenging, especially at ambient temperature and pressure. Electrochemical hydrogenation (ECH) of quinoline to 1,2,3,4‐tetrahydroquinoline (THQ) at mild conditions using water as the hydrogen source is demonstrated with splendid activity on a Cu‐based nonprecicous catalyst. The yield of THQ is up to ≈100% with ≈100% selectivity at −1.275 V vs Hg/HgO. The real active sites and key intermediates are deciphered, where the Lewis acid‐base sites on the heterointerface of Cu/Cu2O are beneficial to the quinoline adsorption in a dual‐site coordination configuration and water dissociation to afford H*. The presence of Cu0 plays a vital role in inhibiting the binding of H*, which ensures good Faradaic efficiency. In addition, a novel co‐production system by coupling benzyl alcohol oxidation at the anode is established, achieving dual benefits in both energy utilization efficiency and economic benefits. [ABSTRACT FROM AUTHOR]

We report an efficient protocol for oxidation of primary/secondary benzyl alcohols and benzylamines to produce corresponding aldehydes or ketones. Our unified method involves the use of commercially available (diethylamino)sulfur trifluoride (DAST) as a reagent combined with DMSO as solvent and oxidant. The reaction provided corresponding carbonyl compounds in good to excellent yields with high purity and in short reaction times. [ABSTRACT FROM AUTHOR]

Two mononuclear complexes, [Cu(L1)2] (complex 1) and [Cu(HL2)2](NO3)2 (complex 2) where HL1 is 1-((cyclohexylmethylimino)methyl)-naphthalen-2-ol and HL2 is 4-bromo-2-((2-morpholinoethylimino)methyl)phenol, have been synthesized under mild conditions and characterized by different standard analytical methods. Single crystal X-ray diffraction analysis shows that the copper atoms in both copper(II) complexes are in a square planar geometry. These complexes have been used as catalysts in the oxidation of benzyl alcohol and benzyl alcohol with various substituents in the presence of NaOCl as the terminal oxidant. The results show that complex 1 acts as a better catalyst than the other with the highest yield of 91% in the case of 4-methoxy benzyl alcohol oxidation. The copper complex transfers the oxygen of sodium hypochlorite to the alcohol to produce the aldehyde. The use of NaOCl as an oxidant in alcohol oxidation is rare although it is cheap and nonexplosive. [ABSTRACT FROM AUTHOR]

In recent years, high entropy alloys (HEAs) have increasingly received attentions from researchers due to their unique microstructure, good stability and excellent catalytic properties. Much research has recently been carried out to develop synthesis methods and expand the applications of HEAs in various areas. HEAs exhibited excellences in electrocatalysis. This review begins with a brief introduction about the principles and properties of HEAs. The research progress of HEAs as electrocatalysts in the applications of alcohol oxidation reaction, oxygen evolution reaction, hydrogen evolution reaction, oxygen reduction reaction and nitrogen reduction reaction are highlighted. Finally, future research prospects for the application of HEAs are also proposed. • Recent advances on HEAs for electrocatalysis have been reviewed. • Core effects and different applications for HEAs have been introduced. • Future research prospects for the application of HEAs are also proposed. [ABSTRACT FROM AUTHOR]

The regiospecific Cα−Cβ cleavage of allylic alcohols under modified aerobic Mukaiyama hydration conditions is presented. The new methodology can be regarded as an equivalent of a two‐step process, a typical hydration of the parent allylic alcohol followed by a 1,2‐diol cleavage. A broad scope of substrates, both cyclic and acyclic, are applicable, thus introducing substantial structural modification to the core, especially of the former type of substrates. Mechanistic investigation of the reaction reveals the importance of the nearby hydroxyl group for the deviation from the typical Mukaiyama hydration pathway. [ABSTRACT FROM AUTHOR]

Efficient electrocatalysts are critical in the advancement of fuel cell technologies and should have superior activity for alcohol oxidation reactions (AORs). Herein, we report a facile one-pot method to synthesize platinum-bismuth nanoalloy (Pt–Bi) on reduced graphene oxide (RGO), enacting the methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR) in an acidic solution. The reduction of the Pt and Bi precursors is co-mediated via l -ascorbic acid and ethylene glycol (EG) to afford Pt–Bi nanoparticles with an average size of 5.6 nm highly dispersed on the surface of RGO. Pt–Bi nanoparticle decoration is confirmed by transmission electron microscopy (TEM) and energy-dispersive X-ray (EDX). X-ray photoelectron spectroscopy (XPS) results show the existence of the Pt–Bi metallic phase with minimal oxide. Electrochemical experiments using cyclic voltammetry (CV) reveal that the Pt–Bi/RGO catalyst is considerably more active than commercial Pt/C for AORs. Notably, the mass activity (J mass) of MOR is enhanced by 1.3-fold and EOR is enhanced by 2.3-fold, highlighting the influence of the Pt–Bi interfacial concept. Overall, the results suggest that Pt–Bi/RGO is a highly promising candidate for use in direct alcohol fuel cells. Schematic representation of the Pt–Bi/RGO electrocatalyst for methanol and ethanol direct oxidation reactions. [Display omitted] • Pt–Bi alloy on RGO synthesized successfully by a one-pot method. • Pt–Bi/RGO provides more active sites for methanol and ethanol electro-oxidation. • Bi enhances Pt–Bi nanoparticle CO tolerance for alcohol oxidation. • Pt–Bi/RGO shows mass activity of 0.458 and 0.384 mA μg⁻1-Pt for MOR and EOR. • Improved catalyst stability and activity due to Pt–Bi synergy on RGO support. [ABSTRACT FROM AUTHOR]

Hierarchical Co3O4/triple-shelled carbon nitride (Co3O4/TSCN) composite nanocapsules were designed via a multi-step procedure in a controlled manner as a solar-light-driven photocatalyst based Z-scheme system for selective aerobic photooxidation of alcohols (primary and secondary aliphatic and benzylic) to corresponding aldehydes/ or ketones in green media. The structure of the as-prepared photocatalyst was characterized by a series of measurement techniques including FT-IR, XRD, BET, TEM, FE-SEM, EDX, EDX-mapping, TGA, UV–vis DRS, and ICP-OES. The hierarchical Co3O4/TSCN composite nanocapsules demonstrated superior photocatalytic activity in selective aerobic oxidation of alcohols under solar light irradiation in comparison to pure TSCN and Co3O4 NPs. The shell number of the composite nanocapsules and the formation of the hierarchical Co3O4/TSCN Z-scheme photocatalyst can significantly affect the photocatalytic activity. The results indicate the efficient electron transfer, relatively high specific surface area, high donor density, and low band gap as well as the coexistence of micro-, meso- and macropores and also nano-sized crystalline structure (from 1.2 to 95 nm) in heterojunction composite. This novel photocatalytic system kept relatively high catalytic activity after five recycle runs under the same reaction conditions. [ABSTRACT FROM AUTHOR]

Gold-coated magnetic iron oxide nanoparticles (ION) (Fe3O4@Au) were synthesized and utilized as catalyst for alcohol oxidation with tert-butyl hydroperoxide (TBHP). First, iron oxide magnetic nanoparticles (Fe3O4) were prepared and finally coated with a thin layer of gold. Structure and composition of Fe3O4@Au nanocatalyst were characterized by XRD, TGA, and FT-IR analysis. Size and morphology and size of particles were determined through TEM. Surface properties and topographies of coated nanoparticles were investigated by the AFM technique. The magnetic properties of Fe3O4 and Fe3O4@Au nanoparticles were measured by VSM technique. After confirming the structure of gold-coated magnetic ION, its performance for the oxidation of various aliphatic and aromatic alcohols with TBHP was studied in water. Finally, the reusability of Fe3O4@Au nanocatalyst was evaluated after five consecutive cycles in the 4-methoxybenzyl alcohol oxidation. The measured results revealed that the gold-coated iron oxide magnetic nanoparticles can be reused well in the oxidation processes of alcohols with high efficiency. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) regulation for single‐atom nanozymes (SAzymes), e.g. Fe−N−C, is a key scientific issue that determines the activity, selectivity, and stability of aerobic reaction. However, the poor understanding of ROS formation mechanism on SAzymes greatly hampers their wider deployment. Herein, inspired by cytochromes P450 affording bound ROS intermediates in O2 activation, we report Fe−N−C containing the same FeN4 but with tunable second‐shell coordination can effectively regulate ROS production pathways. Remarkably, compared to the control Fe−N−C sample, the second‐shell sulfur functionalized Fe−N−C delivered a 2.4‐fold increase of oxidase‐like activity via the bound Fe=O intermediate. Conversely, free ROS (⋅O2−) release was significantly reduced after functionalization, down to only 17 % of that observed for Fe−N−C. The detailed characterizations and theoretical calculations revealed that the second‐shell sulfur functionalization significantly altered the electronic structure of FeN4 sites, leading to an increase of electron density at Fermi level. It enhanced the electron transfer from active sites to the key intermediate *OOH, thereby ultimately determining the type of ROS in aerobic oxidation process. The proposed Fe−N−Cs with different second‐shell anion were further applied to three aerobic oxidation reactions with enhanced activity, selectivity, and stability. [ABSTRACT FROM AUTHOR]

An open new perspective has been established toward synthesizing eco‐friendly CSA@g‐C3N4 employing surface engineering. The carbon nitride modified through camphorsulfonic acid was designed and developed in a category of the new generation of photocatalysts for the oxidation of benzyl alcohol and thioanisole in the existence of a natural deep eutectic solvent (NADES). In comparison with pure g‐C3N4, not only does CSA@g‐C3N4 exhibit an extraordinarily higher ability for harvesting visible light stemming from declining the recombination rate of electrons/holes dependent on PL results but it also reveals notable photocatalytic oxidation capability in the transformation of alcohols as well as thiols into relevant compounds. In addition, non‐metal compound (CSA) incorporation would result in considerably diminishing the energy band gap value from 2.8 to 2.28 eV to escalate the visible‐light absorption of g‐C3N4. While the conventional consensus implies that inherent properties of photocatalysts bring on high photoactivity, this study indicates that deploying choline chloride–urea deep eutectic solvent as an external factor plays the role of photoactivity accelerator. Furthermore, readily recycling and reusability can be achieved for the photocatalytic setup of CSA@g‐C3N4 ascribed to its heterogeneous nature with no drop in the photoactivity. [ABSTRACT FROM AUTHOR]