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Ga2O3/MCM-41-x (x = 0.4, 0.5, 0.6) heterogeneous catalysts, each with varying levels of Br doping, were synthesized using mesoporous molecular sieves (MCM-41) as a carrier and employed in the synthesis of propylene carbonate (PC) from propylene oxide (PO) and carbon dioxide (CO2). The reaction was conducted under solvent-free and additive-free conditions. Various techniques were utilized to characterize the catalysts' chemical composition, morphology, and structure. The effects of varied reaction conditions on PO conversion and PC selectivity using Ga2O3/MCM-41-0.5 catalysts were investigated. Under the reaction conditions of 120 °C, 3.5 MPa, 10 h and catalyst dosage of 2.6 wt%, the PO conversion and PC selectivity reached 99.7% and 99.1%, respectively. The catalytic impact correlates strongly with the doping amounts of Ga2O3 and Br, primarily due to the interaction of Ga2O3 with the surface of MCM-41, leading to the generation of more basic sites and, consequently, a greater abundance of alkali centers. As a nucleophilic reagent, Br functions synergistically with Ga2O3/MCM-41, augmenting the ring-opening rate of PO and improving the activation ability of CO2. The stability of the catalyst underwent evaluation, revealing a slight decrease in activity after repeated use. The reaction mechanism underlying PC synthesis catalyzed by Ga2O3/MCM-41-0.5 was speculated. [ABSTRACT FROM AUTHOR]

Pt/C and SO42−/ZrO2 were mechanically mixed as the catalysts for p-aminophenol synthesis by catalytic transfer hydrogenation of nitrobenzene in water with formic acid as the hydrogen source. The effect of Pt loading and the solid acid on the reaction was investigated. PAP selectivity reached a maximum at a loading of 1 wt%. The characterization results revealed the presence of three valence states of Pt. Pt0 was beneficial for the nitrobenzene hydrogenation, while higher valence Pt contributed to the formic acid decomposition. The catalytic performance of different solid acid catalysts, including HZSM-5, Hβ, SO42−/ZrO2 and SO42−/TiO2, was compared. It was found that Lewis acid sites with strong acid strength were favorable for p-aminophenol formation, and SO42−/ZrO2 showed higher catalytic activity for the reaction. Using Pt/C + SO42−/ZrO2 as the catalyst, the reaction conditions were optimized. Under the optimal reaction conditions, the nitrobenzene conversion and the p-aminophenol selectivity were 80.0% and 47.6%, respectively. The reaction mechanism was also proposed based on the main by-products of the reaction. [ABSTRACT FROM AUTHOR]

A carbon‐based solid acid with a large surface area (CSALA; SBET = 237.9 m2/g) was prepared from peanut shells. Compared with a CSA with a small specific surface area (SBET = 5.6 m2/g), the CSALA enabled greater cellulose hydrolysis. Under optimized conditions, the yield of reducing sugars over 2.5 h at 110°C was 60.5% using the CSALA. When a CSA was used, the yield of reducing sugar only reached 58.6% after 4 h at the same temperature. The results showed that the CSALA had higher activity because of its larger specific surface area and more numerous surface acid centers. However, it was unstable and was deactivated after one use. The loss of some of the sulfonic groups on the CSALA surface, and the conversion of some of those groups to sulfate groups under the action of 1‐butyl‐3‐methylimidazolium chloride ionic liquid were the main reasons for the deactivation of the CSALA. In addition, most of the residual sulfonic groups were located in the micropores of CSALA and could not participate in the cellulose hydrolysis reaction. [ABSTRACT FROM AUTHOR]

Gas-assisted low-gradient magnetic separation (GAMS) was proposed for removing Congo red (CR) from wastewater. GAMS included the adsorption removal process of nanoparticles for CR and GAMS recovery process for CR-loaded nanoparticles from wastewater. Polyethylene glycol (PEG) modified Fe3O4 (Fe3O4/PEG) nanoparticles showed maximum saturated adsorption capacity of 133.3 mg/g. The results indicated that the adsorption process conditions changed the loading amounts of CR on Fe3O4/PEG nanoparticles, showing indirect effect on the separation efficiency of GAMS. And the separation performance of GAMS could be significantly improved by changing gas flow rate, ionic strength, pH, and dyes loading amounts on nanoparticles. The comparison results of MS and GAMS suggested that the limitation of magnetic force on the capture distance could be overcome and the separation efficiency of MS could be significantly improved by the bubbles. These made it feasible to rapidly recover dyes-loaded nanoparticles from large volume wastewater. GAMS combined the efficient removal of dyes by magnetic nanoparticles with rapid recovery of dyes-loaded nanoparticles from large volume wastewater, showing great potential for wastewater treatment. [ABSTRACT FROM AUTHOR]

We prepared a CuO–CeO2–M catalyst, where M refers to MOFs, by calcinating a mixture of Cu–benzene-1,3,5-tricarboxylate (BTC) and Ce–(BTC), which was obtained through a process similar to co-precipitation under mild conditions. The catalyst exhibited good performance for CO oxidation and almost completely converted CO at 80 °C. However, CO conversion over a CuO–CeO2–C catalyst, where C refers to co-precipitation, prepared by co-precipitation was only 81% at 80 °C. To understand the reason for the difference in activity between the two catalysts and clarify the effect of BTC ligands on CuO–CeO2–M, we prepared CuO–CeO2–H1 and CuO–CeO2–H2 catalysts by adding various quantities of benzene-1,3,5-tricarboxylic acid (H3BTC) during the co-precipitation process. The catalytic activity was in the following order: CuO–CeO2–M > CuO–CeO2–H1/H2 > CuO–CeO2–C. There were three distinct copper species in the aforementioned catalysts: highly dispersed copper, copper doped into CeO2 lattices, and crystalline copper. For CuO–CeO2–M catalyst, the high content of Ce3+, Cu+, and surface-adsorbed oxygen was the cause for high activity. By adding H3BTC, the Cu+ content and dispersion of copper species in CuO–CeO2–H1/H2 was higher than that in CuO–CeO2–C. Accordingly, organic ligands can separate metal ions and prevent aggregation of oxides during calcination, which facilitates dispersion of copper species. In addition, CO can be released by thermal decomposition of organic ligands during calcination; CO is conducive to the formation of more Cu+ in the catalyst. [ABSTRACT FROM AUTHOR]