Catalysis Communications最新文献

MIL-101(Cr) metal-organic frameworks and novel zinc oxide-MIL101(Cr) metal organic frameworks (ZnO-MIL101(Cr)) were prepared by hydrothermal technique at 160 °C and 220 °C for photodegradation of phenanthrene (PHE) in visible light. X-ray diffraction (XRD) analysis indicated a reduction in crystallite sizes of ZnO-MIL101(Cr) when compared to MIL101(Cr). However, incorporation of zinc oxide (ZnO) did not disrupt the MIL101(Cr) structure. ZnO-MIL101(Cr) exhibited high BET surface area (>1000 m²/g) when compared to MIL-101(Cr). These composites have lower bandgaps of ∼3.20 eV, than MIL-101(Cr) (3.5 eV). Optical studies reveal that incorporation of ZnO into MIL101(Cr) delays recombination of electron-hole pairs. These factors lead to ZnO-MIL101(Cr) having similar PHE degradation (98%), however within a shorter time when compared to MIL101(Cr). Catalysts followed the pseudo first-order kinetic model with ZnO-MIL101@220 °C having a rate constant of 2.83 × 10⁻² min⁻¹. This is 2.3× and 1.1× higher than ZnO and the respective MIL101(Cr), correspondingly. Scavenging tests reveal that the hydroxyl radical (•OH) is the primary reactive species for PHE degradation. A degradation mechanism is proposed based on this finding.

Photocatalytic hydrogen production is recognized as a promising approach to produce greener hydrogen. The development of next-generation photocatalytic materials aims to enhance photocatalysis efficiency. Perovskite, a third-generation photocatalytic material, has gained interest in photocatalytic water splitting due to its optical stability, structural flexibility, bandgap tunability, and charge transfer efficiency. However, the perovskites are not able to achieve the targeted efficiency. Perovskite-based Z-scheme heterojunction photocatalysts can enhance efficiency. This review gives special attention to types and the formation of Z-schemes. In particular, photocatalysts involved in all-solid-state and direct Z-scheme for photocatalytic hydrogen production have been discussed.

We demonstrated that [Bmim]Br can act as an efficient catalyst exhibiting excellent selectivity in the aerobic oxidation of cumene by decreasing the amount of ILs. The optimal CHP selectivity of 95.4% with 23.6% conversion was obtained from cumene catalyzed by [Bmim]Br at optimal conditions. The kinetic study showed that the reaction follows 1.2-order kinetics. The mechanism study indicated that [Bmim]Br could accelerate the initiation step, transforming the cumene to cumyl radical(R•). The positive effect of hydrogen of imidazolium on the reaction has been observed in the aerobic oxidation of the cumene.

A study has synthesized a composite of carbonaceous nanomaterials, including functionalized multi-walled carbon nanotubes (f-MWCNT) and reduced graphene oxide (rGO), with 1D-architectured zinc oxide nanorods (ZnO NRs), for applications in adsorption and sunlight-assisted photocatalytic degradation. We modified the composite with 1% w/w rGO and f-MWCNT. We studied the adsorption and photodegradation of azo dyes using ZnO and its nanocomposites. The photocatalysts of RZnO and CZnO nanocomposite degraded RhB, MB, CV, MO, and CR dyes with a degradation percentage of 92 to 97%. The nanocomposite demonstrated superior antimicrobial and antioxidant properties compared to ZnO NRs, highlighting their potential in drug delivery.

This study assessed the efficacy of ZrO₂-based catalysts with different Mn(II) and Co(II) metal loadings for catalytic degradation of ibuprofen using peroxymonosulfate anion as oxidant. The support was prepared via co-precipitation, and metal ion deposition was achieved through incipient wetness impregnation. Catalysts were characterized by atomic absorption spectrometry, X-ray diffraction, Fourier-Transform infrared spectroscopy, and scanning electronic microscopy. Optimal experimental conditions resulted in complete ibuprofen degradation in 30 min, with 63.3% mineralization. The best-performing catalyst was reusable up to three times. Both sulfate and hydroxyl radicals were generated in the oxidant activation process.

Selective conversion of furfural can prepare various important chemicals, marking it as a prominent area of interest in biomass utilization. This paper reviews the latest progress in the direct conversion of furfural or its derivatives to 1, 5-pentanediol, 1, 2-pentanediol and 1, 4-pentanediol which are widely used high-value fine chemicals with great development potential in application. The recent catalytic methodologies employed in the synthesis of pentanediols from furfural and its derivatives, encompassing both noble metal and non-noble metal catalysts, have been comprehensively summarized. Furthermore, the challenges and opportunities in biomass-based pentanediols synthesis are analyzed, emphasizing catalyst importance and sustainable, eco-friendly production for pentanediols from renewable resources.

Metal-organic frameworks (MOFs)-based carrier, MIL-100(Fe), was synthesized by hydrothermal method and Ni was supported on the MIL-100(Fe) by wet impregnation method to prepare the catalysts for selective catalytic reduction of NO with C₃H₆ (C₃H₆-SCR). The addition of Ni significantly improved the reactivity of C₃H₆-SCR. At 275 °C, the NO conversion of MIL-100(Fe) was 74.5%, whereas the NO conversion of 5.8%Ni/MIL-100(Fe) with 100% N₂ selectivity was 100%. The in-situ DRIFTS prove that the interaction between NO₂⁻/NO₃⁻ and C_xH_yO_z substances generated intermediate isocyanates (R-NCO), and the reaction pathway was proposed based on the DRIFTS results to understand the mechanism.

Hemicellulose hydrolysate upgrading was performed over BEA zeolites containing Si/Al equal to 12 and 19. A model hydrolysate was prepared considering typical concentrations of xylose, arabinose, furfural and acetic acid representative of hemicellulose hydrolysate from Brazilian sugarcane bagasse. BEA zeolite showed to be an effective catalyst to promote the hydrolysate upgrade into platform molecules. Acetic acid participated in the reaction as a homogeneous Brønsted co-catalyst but BEA zeolite plays a decisive role as it strongly affects products distribution. Pentoses with different molecular configurations produced different products due to hydroxyls steric positions. The presence of acetic acid did not damage the catalyst.

The increasing focus on sustainability has prompted researchers to investigate innovative catalytic methods for converting acids produced from biomass into value added ester compounds. The present study focuses on the efficient conversion of diverse biomass-derived acids into esters through the utilization of zeolite-based catalysts, capitalizing on their unique structural and acidic properties. The utilization of esters encompasses a wide range of applications, making them highly versatile as both platform chemicals and biofuels. Recent development and enhancement of catalytic systems based on zeolites are specifically reviewed for the efficient synthesis of ester compounds with significant commercial value from biomass derived acids.

The 2D transition metal WSe₂, a strong photocatalyst, was combined with BiVO₄ to create a p-n heterojunction photocatalyst using a hydrothermal process. The resulting 10% WSe₂/BiVO₄ (in the synthesized material, the mass ratio of WSe₂ to BiVO₄ is 1:10) composite showed impressive 94.5% efficiency in Methylene Blue (MB) degradation under visible light. Even after eight cycles, it maintained a 72% degradation rate, demonstrating robust photocatalytic stability. Experiments, including ·O²⁻ and h⁺ capture and ESR analysis, revealed their vital roles in photocatalytic degradation. The exceptional performance of WSe₂/BiVO₄ is attributed to the internal electric field formed between WSe₂ and BiVO₄, enhancing carrier mobility.