Catalysis Letters最新文献

The effect of organic precursors on catalysts was studied and the preparation of catalyst and reaction conditions were optimized. A 91% selectivity of 2,5-dimethylfuran (DMF) from the hydrogenolysis of 5-hydroxymethylfurfural (HMF) was obtained on a Mo monometallic catalyst, in which nitrogen doping played a key role. Density functional theory (DFT) shows that Mo sites with N, O and C coordination have moderate adsorption strength of HMF and H₂ and lower energy barrier of key steps compared with pure molybdenum nitride, molybdenum carbide and molybdenum oxide, which may be conducive to catalytic hydrogenolysis of HMF.

Graphical Abstract

An efficient C-S cross-dehydrogenative coupling (CDC) has been achieved using rGO/Fe₃O₄-CuO as a robust nanocatalyst in the presence of TBHP and SDS as a surfactant for the thioesterification of cost-effective methylarenes with thiols in water. This heterogeneous Cu catalyst exhibited excellent performance and recyclability in the synthesis of thioesters without the assistance of any directing group.

Graphical Abstract

Magnetic reduced graphene oxide supported CuO catalyzed cross-dehydrogenative coupling of thiols and alkylbenzenes: Direct access to thioesters.

The immobilized horseradish peroxidase (P1-HRP) was prepared based on the affinity interaction between the phenylborate group in mVBA-b-p (AAm co AN) polymer (P1) and the adjacent dihydroxy group in horseradish peroxidase (HRP). The immobilization conditions of P1-HRP were optimized. Under the conditions of P1 concentration of 20 mg/mL, pH 8, temperature of 50 ℃, and immobilization time of 2 h, the HRP was immobilized to obtain the optimal immobilization amount (84.7 mg/g). The successful preparation of P1-HRP was demonstrated through characterizations such as laser scanning confocal microscopy (LCSM), scanning electron microscope (SEM), dynamic light scattering (DLS) and thermogravimetric analyzer (TGA). P1-HRP exhibited excellent pH stability, thermal stability and storage stability compared to the free horseradish peroxidase. P1-HRP had shown good application value in the degradation of phenol pollutants. After 10 repetitions of phenol degradation, the relative enzyme activity of P1-HRP could still be retained by 55.62%, indicating its good reusability. The optimal conditions for the catalytic degradation of phenol by P1-HRP were optimized. After catalytic degradation of phenol for 60 min under the same conditions, the degradation rate of P1-HRP (92.33%) was higher than that of free horseradish peroxidase (85.32%).

Graphical abstract

Ni-W catalysts find extensive application in catalysis; however, the impact of diverse morphologies on their catalytic activity remains a relatively unexplored area. Using hydrothermal/solvothermal synthesis methods, we successfully synthesized Ni-W catalysts with various morphologies, including sheet-like, sphere-like, rod-like, flower-like, and particulate-like structures. Comprehensive investigations into the influence of morphology on the catalytic activity of these Ni-W catalysts were conducted, employing techniques such as SEM, XRD, XPS, TG-DTG, BET, H₂-TPR, and H₂-TPD. Remarkably, the flower-like Ni-W catalyst displayed exceptional catalytic properties in ethylbenzene hydrogenation, exhibiting not only high hydrogenation activity but also superior sulfur resistance. Consequently, the flower-like Ni-W catalyst holds great potential for applications in industrial catalysis.

Graphical Abstract

Green heterogeneous bifunctional catalyst is sustainable for the production of biodiesel owning to its reusability, eco-friendly, and bifunctionality. In this work, a green heterogeneous bifunctional Zeolite-A/Biochar (Z-A/BC) catalyst was synthesized for the production of biodiesel from waste cooking oil (WCO) through one-pot esterification-transesterification reaction. The functional group, elemental composition, crystallographic structure, and morphology of the synthesized catalyst were characterized using FT-IR, EDX, XRD, and SEM, respectively. Furthermore, the catalytic proficiency of the synthesized catalyst was tested by optimizing methanol to oil ratio, catalyst amount, temperature, and reaction time. The maximum biodiesel yield (86.22%) was achieved at 2.5% wt. of catalyst amount, 10:1 of methanol to oil molar ratio, 70 °C of reaction temperature, and 240 min of reaction time. The synthesized Z-A/BC catalyst showed apparent catalytic efficiency than its parent materials Z-A (69.42%) and BC (74.27%). The recyclability of Z-A/BC catalyst was also found to be 86.22, 82.98, 79.08, 62.87, and 76.84% for 1^st, 2^nd, 3^rd, 4^th, and 5^th cycles, sequentially which is cost effective. Furthermore, the physicochemical properties such as density, ash content, FFA, acid value, saponification value, and kinematic viscosity of the produced biodiesel were analyzed by comparing with standards. These results showed good agreement with ASTM and EN14214 biodiesel standards. Therefore, the produced biodiesel using heterogeneous bifunctional Z-A/BC catalyst from WCO could be used as an alternative engine fuel with/without blending with commercial diesel.

Graphical Abstract

Fabrication of highly efficient and earth-abundant bifunctional electrocatalyst to accelerate the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are critical for overall water splitting. In this work, bimetallic Co/Mo oxides modified reduced graphene oxide (rGO) was synthesized using a simple one-pot hydrothermal method, which significantly improved the electrocatalytic activity in both HER and OER. Under the optimal conditions, the double layer capacitance of rGO modified by Co/Mo bimetal is 78.08 mF cm⁻². The overpotential required for HER to reach -10 mA cm⁻² current density is 488 mV, the dynamic Tafel slope is 126 mV dec⁻¹. The overpotential required for OER to reach 10 mA cm⁻² current density is 420 mV, the slope of kinetic Tafel is 169 mV dec⁻¹. This work provides a new prospect for the rational design and fabrication of efficient HER/OER bifunctional electrocatalysts in electrochemical energy device application.

Graphical Abstract

A sequence of MgO-ZrO₂ mixed oxides with varying their ratios were synthesized by adopting co-precipitation method. These catalysts characteristics were deduced from different spectroscopic methods and used for vapor phase cross-ketonization of pivalic acid with acetic acid to produce pinacolone at atmospheric pressure. The characterization results indicated that at a high ZrO₂ molar ratio, Mg_xZr_1-xO₂-x mixed oxide phase is formed, and it accounted for the presence of strong basic sites. MgO-ZrO₂ mixed oxides ketonization activity is superior to individual oxides and the overall activity mainly depended on their molar ratio, calcination temperature, and presence of mixed oxide phase. The basicity of the MgO-ZrO₂ mixed oxide catalyst is responsible for the high conversion of pivalic acid. The ketonization reaction is carried under different reaction parameters and optimized conditions were established. The catalysts are showed stability during the time on stream analysis.

Graphical Abstract

Developing highly efficient catalysts for oxygen evolution reactions (OER) in complex water environments is crucial for promoting the photovoltaic electrolysis of water splitting for hydrogen production in arid areas. However, traditional catalysts often exhibit limitations in terms of reaction kinetics and electrode corrosion resistance. In this work, we successfully prepared a self-supporting perovskite complex oxide La_0.7Sr_0.3CoO_3-δ/NF (LSC/NF) catalyst by means of simple hydrothermal synthesis combined with programmed annealing, and successfully applied to OER reaction in oilfield wastewater. In alkaline oilfield wastewater, at a current density of 10 mA cm⁻², LSC/NF requires only 411 mV of overpotential, which is lower than that of LSC (493 mV) and traditional catalyst RuO₂ (451 mV), suggesting a high OER catalytic activity. The good electrocatalytic activity can be attributed to its superhydrophilicity, increased electrochemical active surface area, faster reaction kinetics and higher oxygen vacancy concentration. This research offers valuable new insights for the development of OER electrocatalysts with high catalytic activity in complex water systems in arid areas.

Graphical Abstract

A self-supporting perovskite oxide catalyst La_0.7Sr_0.3CoO_3-δ/NF was synthesized by a simple process combining hydrothermal and annealing. The growth of perovskite oxide nanosheets directly on the conductive nickel foam matrix gives the catalyst a strong hydrophilicity and significantly expands its electrochemical active surface area, thus enhancing the OER activity of LSC/NF in oilfield wastewater.