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Development of an energy‐efficient and economical route is necessary for society to synthesize green biofuels. Herein, cobalt‐doped tungstophosphoric acid (Co‐HPW) is in‐situ impregnated in the Zr‐based metal–organic framework (MOF‐801) forming composite of Co‐HPW/MOF‐801. The chemical composition, morphology, and acidic sites of the Co‐HPW/MOF‐801 composite were analyzed through x‐ray diffractometer (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM), energy‐dispersive x‐ray spectroscopy (EDS), thermogravimetric analysis (TG), N2 physisorption, ammonia temperature‐programmed desorption (NH3‐TPD), pyridine‐adsorbed infrared spectra (Py‐FTIR), and x‐ray photoelectron spectroscopy (XPS). The catalytic performance of the as‐synthesized catalyst was explored to catalyze esterification of lauric acid (LA) with methanol. The outcomes revealed that the Co‐HPW/MOF‐801 nanocatalyst achieved a high conversion of 86.3% under the optimized reaction condition (catalyst amount of 0.15 g, temperature of 100°C, time of 4 h, and methanol/LA molar ratio of 20:1). The excellent catalytical performance is mainly due to the large BET surface area, exposure of more active centers from available pore structure, and simultaneous possession of high Lewis and Brønsted acidity. Furthermore, the kinetic study revealed that the reaction process was kinetically controlled and the activation energy was found to be 42.1 kJ/mol. The results suggest that the synthesized Co‐HPW/MOF‐801 nanocatalyst is an environmental greenness, low cost, and suitable for easy scale‐up for the production of biofuels. [ABSTRACT FROM AUTHOR]

In this study, the bimetallic Ni-Zr MOF-derived nickel-zirconium oxide (Ni-Zr-O)-impregnated silicotungstic acid (HSiW) nanocomposite catalyst (HSiW@Ni-Zr-O) was prepared via a hydrothermal procedure followed by a pyrolysis treatment, and its structural, morphological, and surface components and oxidation states were characterized by using XRD, FTIR, TPD-NH3, SEM, TEM, N2 physisorption, and XPS analyses. Then, the nanocomposite catalysts were successfully applied to the esterification of oleic acid (OA) with methanol. According to its characteristics, the obtained HSiW@Ni-Zr-O-1 catalyst would generate larger pores, a higher acidity, and active interfaces at the calcining temperature of 300 °C. Therefore, HSiW@Ni-Zr-O-1 exhibits an excellent catalytic activity of 95.2% under optimal reaction conditions. Additionally, the catalyst can be reused with a good catalytic activity after nine cycles. This study highlights the opportunity of using bimetallic MOFs as precursors to the synthesis of highly nanoporous metal oxide, which supports the larger-industrial scale production of biofuels. [ABSTRACT FROM AUTHOR]

The impregnation of phosphotungstic acid (HPW) with porous cobalt-cerium oxide (HPW@CoCeO) has been prepared by pyrolysis of CoCe-MOF and used for the production of methyl oleate from oleic acid and methanol. FTIR, XRD, SEM, TEM, N2 adsorption/desorption, and NH3-TPD were characterized for the prepared composites. Simultaneously, the effects of reaction time, substrate molar ratio, temperature, and catalyst loading on catalytic activity were highlighted, and the conversion of 67.2% was reached after 4 h at 60°C. Importantly, HPW@CoCeO was reusabe and reused more than eight times, and the oleic acid conversion could be maintained at 61.8% without significant activity loss. Thus, the HPW@CoCeO composite could be used as acid catalysts for sustainable energy production. [ABSTRACT FROM AUTHOR]

MIL-101(Fe) was explored for the first time for the catalytic conversion of glucose into lactic acid (LA). The as-synthesized MIL-101(Fe) was successfully characterized, and its higher specific surface area, porosity, and feasible acid properties were confirmed to determine the remarkable catalytic activity in glucose-to-LA conversion (up to 25.4% yield) compared with other catalysts like MIL-101(Cr, Al) and UiO-66(Zr). The reaction parameters including temperature, reaction time, and substrate species as well as catalyst reusability were discussed. [ABSTRACT FROM AUTHOR]

Direct conversion of fructose into 5-hydroxymethylfurfural (HMF) is achieved by using modified aluminum-molybdenum mixed oxide (S-AlMo) as solid acid catalysts. The synthesized catalyst was characterized by powder XRD, nitrogen adsorption-desorption isotherm, NH3-TPD, and SEM. As a result, the presence of strong acidity, mesostructures, and high surface area in the S-AlMo catalyst was confirmed by nitrogen adsorption-desorption isotherm and NH3-TPD studies. A study by optimizing the reaction conditions such as catalyst dosage, reaction temperature, and time has been performed. Under the optimal reaction conditions, HMF was obtained in a high yield of 49.8% by the dehydration of fructose. Moreover, the generality of the catalyst is also demonstrated by glucose and sucrose with moderate yields to HMF (24.9% from glucose; 27.6% from sucrose) again under mild conditions. After the reaction, the S-AlMo catalyst can be easily recovered and reused four times without significant loss of its catalytic activity. [ABSTRACT FROM AUTHOR]

Highlights: [•] Ce/MCM-41 was prepared and used as a heterogeneous catalyst in ozonation process. [•] Ce/MCM-41 exhibited highly catalytic activity on ozonation of p-CBA in water. [•] Higher conversion rate of organic chlorine was observed in Ce/MCM-41/O3 process. [•] There was a synergetic effect between O3 and Ce/MCM-41/O3 adsorption. [•] Mechanism of p-CBA degradation and generation of hydroxyl radicals was proposed. [Copyright &y& Elsevier]

Abstract: MCM-41and iron-substituted MCM-41 (Fe-MCM-41) were synthesized successfully and characterized using X-ray diffraction (XRD), nitrogen adsorption–desorption and transmission electron microscopy (TEM). The mesopores of the sample remained well ordering and of hexagonal structure. Fe-MCM-41 samples possessed high BET surface areas, high pore volumes and narrowed pore size distribution. Their catalytic activities were compared in terms of p-chlorobenzoic acid (p-CBA) and TOC removal. Ozonation catalyzed by Fe-MCM-41 exhibited extraordinarily high catalytic performance over other studied processes. 100% conversion of p-CBA and 91.3% TOC were achieved in 10min and 60min, respectively. Fe-MCM-41 as a novel heterogeneous catalyst in ozonation process was addressed. The presence of tert-butanol (TBA) inhibiting the degradation of p-CBA in the Fe-MCM-41/O3 process verified that the hydroxyl radicals derived from ozone decomposition were responsible for the improvement of catalytic ozonation. The mechanism explaining the formation of hydroxyl radicals on Fe-MCM-41 surface was proposed. Negative centers or Brönsted acid sites developed by the substitution of trivalent iron into the walls of MCM-41 and the hydroxyl groups formed as a result of coordinative unsaturation were found to be the active sites enhancing catalytic performance. The superior stability of iron ions in Fe-MCM-41 catalyst during the ozonation process was also examined. [Copyright &y& Elsevier]

A hollow core-shell nanosphere with sandwiched Pd nanoparticles between two-layered mesoporous silica exhibited outstanding catalytic activity and hydrothermal stability in Suzuki coupling reactions of aryl bromides and arylboronic acids. • Synthesis of Pd based sandwich-like hollow nanoporous catalyst. • Comparison of the catalytic efficiency of immobilized and free nanocatalysts. • General applicability of sandwich-like hollow nanoporous catalyst. • High hydrothermal stability of immobilized nanocatalyst. A hollow core-shell nanosphere with sandwiched Pd nanoparticles between two-layered mesoporous silica was designed through layer-by-layer assembly. The nanocomposite exhibited outstanding catalytic activity and thermal stability in Suzuki coupling reactions of aryl bromides and arylboronic acids. The conversion of bromobenzene was up to 82.8% in 1 h and 68.2% in 5 min, and the sandwich structure was well-kept after running five cycles, with few Pd NPs mass loss. [ABSTRACT FROM AUTHOR]