Oxidation Of Alcohols Research Articles

Naphthalene Diimide and Bis-Heteroleptic Ru(II) Complex-Based Hybrid Molecule with 3-in-1 Functionalities.

Multipurpose applications of a newly developed homobimetallic Ru(II) complex, Ru-NDI[PF6]4, which incorporates 1,10-phenanthroline and triazole-pyridine ligands and linked via a (-CH2-)3 spacer to the reputed anion-π interacting NDI system, are described. Solution-state studies of the bimetallic complex, including EPR, PL, UV-vis, and NMR experiments, reveal two sequential one-electron transfers to the NDI unit, generating NDI⋅- and NDI2- in the presence of F- selectively. This process inhibits the primary electron transfer from Ru(II) to the NDI unit, thereby allowing the 3MLCT-based emission of the complex to be recovered, resulting in a corresponding ten-fold increase in luminescence intensity. DFT and TD-DFT computational studies further elucidate the experimentally observed absorption spectra of the complex. Secondly, CT-DNA binding studies with the complex are performed using various spectroscopic analyses such as UV-vis, PL, and CD. Comparative DNA binding studies employing EB and molecular docking reveal that the binding with CT-DNA occurs through both intercalative and groove binding modalities. Thirdly, the photocatalytic activities of the complex towards C-C, C-N, and C-O bond formation in organic cross-coupling reactions, including the amidation of α-keto acids to amines and the oxidation of alcohol to aldehydes, are also demonstrated.

Outstanding Activity and Durability of Supported NiCo2O4 Nanoparticles for Direct Ethanol Fuel Cells

ABSTRACTThe 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.

Selective and fast oxidation of alcohol to aldehyde using novel catalytic deep eutectic solvent surfactants.

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 15min, 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.

Celebrating Ten Years of Covalent Organic Frameworks for Solar Energy Conversion: Past, Present and Future

AbstractAccelerated anthropogenic emission of greenhouse gases due to increasing energy demands has created a negative impact on our planet. Therefore, the replacement of fossil by renewable energy resources has become of paramount interest, both societally and scientifically. It is within this setting that organic photocatalysts have emerged as a new generation of earth‐abundant catalysts for the conversion of solar radiation into chemical energy. In 2014, the first example of a covalent organic framework (COF) photocatalyst for the hydrogen evolution reaction was reported by our group, which has not only marked the beginning of COF photocatalysis for solar fuel production but also helped to accelerate research into “soft photocatalysis” based on porous polymers in general. In the last decade, significant progress has been made toward developing COFs as robust, molecularly precise platforms emulating artificial photosynthesis. This mini‐review commemorates the 10th anniversary of COF photocatalysis and gives a brief historical overview of the milestones in the field since its inception in 2014. We review milestones in the development of COFs for solar fuel production and related photocatalytic transformations, including hydrogen evolution, oxygen evolution, overall water splitting, CO2 reduction, N2 fixation, oxygen reduction, and alcohol oxidation. We discuss lessons learned for the design of structure‐property‐function relationships in COF photocatalysts, and future perspectives and challenges for the field of “soft photocatalysis” are given.

Celebrating Ten Years of Covalent Organic Frameworks for Solar Energy Conversion: Past, Present and Future.

Accelerated anthropogenic emission of greenhouse gases due to increasing energy demands has created a negative impact on our planet. Therefore, the replacement of fossil by renewable energy resources has become of paramount interest, both societally and scientifically. It is within this setting that organic photocatalysts have emerged as a new generation of earth-abundant catalysts for the conversion of solar radiation into chemical energy. In 2014, the first example of a covalent organic framework (COF) photocatalyst for the hydrogen evolution reaction was reported by our group, which has not only marked the beginning of COF photocatalysis for solar fuel production but also helped to accelerate research into "soft photocatalysis" based on porous polymers in general. In the last decade, significant progress has been made toward developing COFs as robust, molecularly precise platforms emulating artificial photosynthesis. This mini-review commemorates the 10th anniversary of COF photocatalysis and gives a brief historical overview of the milestones in the field since its inception in 2014. We review milestones in the development of COFs for solar fuel production and related photocatalytic transformations, including hydrogen evolution, oxygen evolution, overall water splitting, CO2 reduction, N2 fixation, oxygen reduction, and alcohol oxidation. We discuss lessons learned for the design of structure-property-function relationships in COF photocatalysts, and future perspectives and challenges for the field of "soft photocatalysis" are given.

Highly-dispersed CdS nanoparticles coating hierarchical Ni@NC derived from ultrathin nanosheets NMOF-Ni: Photocatalytic hydrogen evolution coupled with alcohol oxidation

Photocatalytic water-splitting into H2 in conventional procedures often requires sacrificial agents to consume unutilized holes to boost the reaction. Herein, we cast off the dependence on the addition of sacrificial agents and develop a dual-functional photocatalyst CdS/Ni@NC for coupling H2 evolution with value-added benzyl alcohol (BA) oxidation in anaerobic aqueous solution, wherein CdS/Ni@NC was synthesized by in-situ anchoring of CdS nanoparticles (NPs) onto NMOF-Ni ultrathin nanosheets-derived nitrogen-doped wrinkled graphitic carbon layers encapsulated metallic Ni NPs (Ni@NC). The optimized photocatalyst CdS/Ni@NC(5) achieves a high visible-light-driven H2 evolution rate of 1881 μmol·g−1·h−1 and a benzaldehyde (BAD) yield of 3254.2 μmol·g−1·h−1, with nearly 100 % selectivity over a 6 h period, which are 32.6 and 10.5 folds of that for CdS alone, respectively. Further in-depth experimental characterizations reveal that the hierarchical Ni@NC serves as an ideal support to enable high dispersion of CdS NPs, thus improving light absorption and facilitating full contact with reactants. Besides, the widely distributed Ni NPs, effectively shielded by nitrogen-doped wrinkled graphitic carbon layers, can not only promote photogenerated charge transfer for enhanced H2 production but also facilitate the cleavage of the Cα–H bond in BA, contributing to achieving high aldehyde selectivity. This study, integrating carbonized ultrathin nanosheets NMOF-Ni with CdS to synergistically enhance surface redox reactions, holds significant promise for advancing the development of high-performance photocatalysts for integrated production of solar hydrogen and value-added solar chemicals.

Efficient in-situ synthesis of heterocyclic derivatives from benzyl alcohols using pyrazinium chlorochromate-functionalized carbonitride as a novel catalyst

The synthesis of efficient organic compounds from simple substrates is both noticeable and important. However, it can be challenging to achieve this target using suitable strategies. To address this issue, pyrazinium chlorochromate (PCC) was used to modify carbonitride nanosheets (CNs) and applied as a heterogeneous catalyst in the oxidation of benzyl alcohols. That can be regarded as innovation in ingenious synthesis of the PCC on the CNs. Then, it was identified by varied techniques such as EDS, FT-IR, XRD, STA and FE-SEM. This process resulted in in-situ synthesis of 1,4-dihydropyridine and 3,4-dihydropyrimidin-2-(1H) one derivatives with excellent yield.

Selective oxidation of benzyl alcohols photocatalyzed by asymmetric cobalt thioporphyrazine supported on alumina

The sunlight-powered transformation of alcohols to corresponding carboxylic acids offers a feasible route for fine chemical synthesis. In this work, the asymmetric cobalt tri(2,3-bis(butylthio)maleonitrile)-(1,4-dithiin) porphyrazine (CoPz(SBu)6(dtn)) was synthesized, more importantly, its single crystal was further obtained by the solvent evaporation method. Then the asymmetric CoPz(SBu)6(dtn) supported on neutral Al2O3 particles to form composite photocatalyst CoPz(SBu)6(dtn)@Al2O3, which possessed strong visible light absorption. Under simulated sunlight irradiation using a xenon lamp, the composite photocatalyst CoPz(SBu)6(dtn)@Al2O3 exhibited excellent photocatalytic activity for selective oxidation of benzyl alcohol to benzoic acid in water under conditions of green H2O2 as oxidant and K2CO3 as additive. The conversion of benzyl alcohol was up to 53.8 % together with 99 % selectivity of benzoic acid over composite photocatalyst CoPz(SBu)6(dtn)@Al2O3. Meanwhile, this photocatalytic system had feasible substrate generalizability and excellent photocatalytic activity for substituted benzyl alcohols containing both electron-donating and electron-withdrawing substituents. The composite photocatalyst CoPz(SBu)6(dtn)@Al2O3 exhibited excellent photocatalytic durability, which was confirmed by the recycling experiments. This work manifests the asymmetric thioporphyrazine as photocatalyst is feasible in implementing sunlight-powered selective transformation.

Regulating the electronic structure of nickel phosphides via interface engineering and molybdenum doping boosts benzyl alcohol oxidation coupled with hydrogen production

Coupling the electrocatalytic benzyl alcohol oxidation reaction (BAOR) with hydrogen evolution reaction (HER) presents a favorable energy conversion method. However, the development of highly efficient bifunctional electrocatalysts poses significant challenges. In this study, a Mo doped biphasic Ni2P-Ni12P5 heterostructure (Mo-Ni2P/Ni12P5@NF) has been developed to serve as the efficient bifunctional electrocatalyst. The Mo-Ni2P/Ni12P5@NF resulted in exceptional activities for both the BAOR and HER. The electrolyzer cell using Mo-Ni2P/Ni12P5@NF as anode and cathode operates at an impressively low cell voltage of merely 1.38 V to achieve the current density of 10 mA cm−2 in a benzyl alcohol-containing aqueous solution. Experimental results and density functional theory (DFT) calculations indicate that the introduction of Mo can significantly modulate the electronic structure of Ni-based phosphide catalysts and adjust for the d-band center of the active Ni sites. This modulation significantly optimizes the adsorption capabilities for both benzyl alkoxide (Ph-CH2O-) and the H* intermediates on Mo-Ni2P/Ni12P5@NF, thereby increasing electrocatalytic activity toward BAOR and HER respectively. Our work offers a valuable insight into designing bifunctional electrocatalysts and highlights the potential of Mo doping systems to produce hydrogen and value-added products efficiently.

Construction of Multiphase Concave Tetrahedral PdInMo Nanocatalyst for Enhanced Alcohol Oxidation

AbstractHeterogeneous 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.

Exploring the possible mechanisms of X-rays treatment for retention aroma volatiles in shiitake mushrooms during low temperature storage

X-rays irradiation has been demonstrated to effectively preserve the freshness of edible fungi and delay the loss of aroma during storage. In this study, shiitake mushrooms were irradiated with X-rays dose of 0.5 kGy and stored at 2 °C for 35 days. Non-irradiated mushrooms were recorded as control group. Results indicated that 0.5 kGy X-rays treatment preserved the flavor quality by exhibiting higher volatile substance content in shiitake mushrooms. X-rays treatment promoted the activities of lipoxygenase (LOX) and alcohol dehydrogenase (ADH) and oxidation of linoleic acid. In addition, the degradation of methionine and cysteine was facilitated by X-rays. Higher enzymes activities for γ-glutamyl transpeptidase (GGT) and cystine sulfoxide lyase (CS lyase) were found in 0.5 kGy X-rays irradiated mushrooms. These findings suggest that the retention of mushroom flavor by X-rays treatment is closely related to fatty acid metabolism, sulfur-containing amino acid metabolism, and lentinic acid metabolism.

Aerobic Oxidation of Alcohol Over Copper(II)‐Based Metal–Organic Framework: Synthesis, X‐Ray Structure, and Catalytic Study

Aerobic Oxidation of Alcohol Over Copper(II)‐Based Metal–Organic Framework: Synthesis, X‐Ray Structure, and Catalytic Study

Terpyridine Ni(II) Complex Grafted CdS Nanorods for Cooperative Selective Benzyl Alcohol Oxidation and Hydrogen Production.

Efficient utilization of photogenerated charge carriers to realize photocatalytic solar fuel production and oxidative chemical synthesis is a challenging task. Herein, a conventional amidation reaction route is adopted to successfully construct a novel composite photocatalyst composed of a Ni(II)-terpyridine complex with carboxyl groups grafted on CdS nanorods (labeled as CdS@Ni(terpyC)2). Experimental results have unequivocally revealed that the as-fabricated composite catalyst exhibited a remarkable enhancement in photocatalytic activity for the dehydrogenation of benzyl alcohol under visible light, demonstrating superior hydrogen evolution efficiency and benzaldehyde selectivity, surpassing both pristine CdS and the blend of CdS and Ni(terpyC)2. The carrier dynamics study demonstrated that the Ni(terpyC)2 on the surface of CdS could quickly extract the photogenerated electrons of CdS, which reduced the carrier recombination efficiency, further improving the photocatalytic activity of the catalyst. This work illustrates the effect of surface active site engineering on photocatalysis and is expected to shed substantial inspiration on future surface modulation and design of semiconductor photocatalysts.

Preparation of rGO/CAU-10 anchored PdPbBi composites and their electrocatalytic ethylene glycol properties

An effective method to improve the catalytic performance of electrocatalytic alcohol oxidation by establishing strong interfacial interactions through novel carrier materials and polymetallic alloys. In this paper, novel polyhedral metal–organic framework Al-based [Al(OH)(mBDC)] (CAU-10) composites with PdPbBi trimetallic particles embedded in folded graphene oxide (rGO) modified by a simple hydrothermal reaction were prepared and applied to the electrocatalytic oxidation reaction of ethylene glycol. The results of electrochemical tests showed that the trimetallic catalysts exhibited excellent electrocatalytic activity compared to commercial Pd/C. In particular, PdPbBi@rGO/CAU-10 has the highest peak current density of 241.82 mA cm−2, which is 8.97 times higher than that of Pd/C (26.92 mA cm−2), and the largest electrochemical active area (ECSA) value of 88.12 mA cm−2, which is 2.40 times higher than that of Pd/C (36.75 mA cm−2). This outstanding electrocatalytic activity is mainly attributed to the polyhedral structure of CAU-10 composite carriers and the abundance of oxygen-containing atoms, which is conducive to the homogeneous loading of metals, at the same time, the strong electronic effect between Pd, Pb and Bi and the abundance of oxygen-containing species provide significant enhancement of electrocatalytic activity and stability, which provides an important reference for the development of electrocatalysts for ethylene glycol fuel cells.

One‐Step Synthesis of Melem‐Based Supramolecular Assemblies and Their Photocatalytic Properties

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%.

Synergetic effect of Fe decorated MnO2 nanocatalyst application in propane and benzyl alcohol oxidation

In heterogeneous catalysis, one of the key challenges is to develop inexpensive and abundant materials. Herein, spherically shaped α–Fe2O3 nanoparticles decorated over MnO2 nanorods surface (Fe/MnO2NRs) was synthesized via hydrothermal followed by co–precipitation methods. Experimental results indicated that the inclusion of Fe in MnO2NRs promotes a strong interaction that increases the reducibility of Mn4+ to Mn3+ and surface adsorbed oxygen (Oads.), which in turn increases the activation of surface oxygen on MnO2NRs. The 10 wt% Fe–loaded catalyst (10Fe/MnO2NRs) exhibited the highest catalytic activity. It was observed that oxidizing 10 % (T10), 50 % (T50), and 90 % (T90) of propane required temperatures of 140 °C, 180 °C, and 220 °C, respectively. This catalyst showed stability in H2O atmospheres and apparent activation energy as low as 52.54 kJ mol−1. In addition, the vapour phase oxidation of benzyl alcohol (BnOH) over different Fe–loaded MnO2NRs catalysts is investigated. The rate of BnOH oxidation over 10Fe/MnO2NRs catalyst is 1.71 times greater than bare MnO2NRs at 240 °C. The increased oxygen vacancies can improve the oxidation activity of propane and BnOH by facilitating the adsorption and activation of O2 to produce reactive oxygen species. This work offers a novel approach to increase manganese oxides surface oxygen activity, which can be used to create efficient catalysts for the low–temperature decomposition of volatile organic compounds (VOCs) and other organic functional group transformations via oxidation reaction.

Proton-Coupled Electron Transfer in Photoelectrochemical Alcohol Oxidation Enhanced by Nickel-Based Cocatalysts.

Using biomass oxidation reactions instead of water oxidation reactions is optimal for accomplishing biomass conversion and effective hydrogen generation. Here, we report that α-Fe2O3 photoanodes with a NiOOH cocatalyst exhibit excellent performance for photoelectrochemical oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). The conversion efficiency for HMF reaches 98.5 %, while the selectivity for FDCA is 94.2 %. We revealed that HMF is oxidized through a spontaneous proton-coupled electron transfer (PCET) process with the high-valent phase of the Ni-based catalyst. The dangling oxygen and bridging oxygen of the high-valent phase species serve as proton-accepting sites. Furthermore, we pointed out that the deprotonated bond dissociation free energy difference between the catalysts and alcohols is the thermodynamic trigger for the PCET process. This study provides a reasonable explanation for the alcohol oxidation reaction, which is beneficial for designing biomass conversion systems.

Proton‐Coupled Electron Transfer in Photoelectrochemical Alcohol Oxidation Enhanced by Nickel‐based Cocatalysts

Proton‐Coupled Electron Transfer in Photoelectrochemical Alcohol Oxidation Enhanced by Nickel‐based Cocatalysts

Three-component NiO/Fe3O4/rGO nanostructure as an electrode material towards supercapacitor and alcohol electrooxidation

A nanocomposite made of nickel oxide and iron oxide (NiO/Fe3O4) and its hybrid with reduced graphene oxide (rGO) as a conductive substrate with a highly functional surface (NiO/Fe3O4/rGO) was synthesized using a simple hydrothermal approach. This study addresses the challenge of developing efficient materials for energy storage and alcohol fuel cells. After confirming the synthesis through structural analysis, the potential of these nanocomposites as supercapacitor electrodes and catalysts for methanol and ethanol oxidation in alcohol fuel cells were evaluated. The synergy of combining the two metal oxides and adding rGO to the composite structure led to excellent electrocatalytic activity in alcohol oxidation. For the modified NiO/Fe3O4/rGO electrode in the methanol oxidation reaction (MOR), a current density of 450 mA/cm2 at 0.67 V and excellent catalyst stability of 98.7% over 20 hours in chronoamperometric analysis were observed. In the ethanol oxidation reaction (EOR), an oxidative current of 235 mA/cm2 at a peak potential of 0.76 V was seen, with catalyst stability of 96.4% after 20 hours. As a supercapacitor electrode, the NiO/Fe3O4 composite demonstrated a specific capacitance of 946 F/g, while NiO/Fe3O4/rGO showed 1155 F/g. The stability of these electrodes after 10000 GCD cycles was 83.6% and 90.6%, respectively. These findings suggest that the proposed structures are cost-effective and reliable alternatives for energy storage and production, suitable for alcohol fuel cells and supercapacitors.

Heteronuclear coordination polymers with imidazole ligand: Synthesis, characterization and alcohol oxidation activities

Two new heteronuclear Cd(II)/Pd(II) coordination polymers, [Cd2(µ-im)2(Him)4Pd(µ-CN)4]n (1) and [Cd(Him)2Pd(µ-CN)4]n (2) (Him: imidazole), have been synthesized under different conditions and characterized using elemental analysis, thermal analysis, FT-IR and Raman spectroscopy, single-crystal and powder X-ray diffraction techniques.. In 1, the Cd(II) ions are bridged by imidazolate ligands to generate 1D chain structure. Neighbouring 1D chains were linked by [Pd(CN)4]2- ions to form 3D framework. In 2, the metal ions are bridged by cyanide ligands to generate 2D [Cd2Pd2(µ-CN)4]n network. Furthermore, catalytic peroxidative oxidation activity of catalysts 1 and 2 was examined on the oxidation of benzyl alcohol using tertiary-butyl hydroperoxide (t-BuOOH) as the oxygen source. The compound 1 exhibited over 90 % product conversion at 80 °C in 24-hour reaction time. In addition, the catalyst exhibited high selectivity towards benzaldehyde and no over-oxidation product (benzoic acid) was detected.