Preparation of Ru/N-doped carbon catalysts by induction of different nitrogen source precursors for the hydroprocessing of lignin oil

The lignin oil produced by rapid pyrolysis of lignin is considered a promising liquid fuel source. Hydrodeoxygenation (HDO) is a kind of efficient method to upgrade the lignin oil, and a high-performance catalyst is key to the hydrodeoxygenation of lignin oil. In this study, a high dispersion and small size Ru nanoparticle loaded N-doped carbon catalyst was derived by the direct pyrolysis of a mixture of ruthenium trichloride and melamine, and it could efficiently convert lignin oil. The lignin oil was completely transformed at 240 °C and 1 MPa H₂, and 36.58% cyclohexane was obtained. The formation, surface area, and nitrogen species of the catalyst could be controlled by changing the precursor of the nitrogen-doped carbon support. The percentage of pyridine nitrogen possessed with melamine as a nitrogen-carbon precursor (31.35%) was much higher than that with urea (16.47%) and dicyandiamide (8.20%) as nitrogen-carbon precursors. The presence of pyridine nitrogen could not only serve as the coordination site for even dispersity and stability of Ru nanoparticles but also regulated the electron density of Ru nanoparticles (NPs) and increased the active site Ru⁰ through electron transfer.

Rapid green-synthesis of TiO2 nanoparticles for therapeutic applications

Nanoparticles (NPs) with sizes ranging from 2 nm to 1 μm find various applications in the field of theranostics. Moreover, if eco-friendly methods are opted for the synthesis of biocompatible and less toxic NPs, then that's a huge success. Titanium dioxide nanoparticles (TiO2 NPs) have been vigorously studied for their use in medical implants, photodynamic therapy, drug delivery, biosensing and as antimicrobial agents. The present study reports the green-synthesis of TiO2 NPs for the first-time using extracts of black pepper (Piper nigrum), coriander (Coriandrum sativum) and clove (Syzygium aromaticum). All three samples of TiO2 NPs were synthesized via a modified sol-gel method under similar environmental conditions. Similar treatments were given to the samples. The procedure adopted for the synthesis ensures the use of non-toxic materials, no production of toxic by-products and rapid synthesis of the TiO2 NPs. The NPs were characterized by X-ray diffraction, high resolution-transmission electron microscopy, energy dispersive spectroscopy, field emission scanning electron microscopy and selected area electron diffraction which confirmed the formation, morphology, crystallinity and size of the TiO2 NPs. These characterizations displayed the similarity index of all three samples. However, photoluminescence and vibrating sample magnetometer studies highlighted the differences among the three samples. All three samples of NPs obtained had a size range of 5-20 nm. Further, the findings showed that different plant extracts result in TiO2 NPs with moderately different characteristics. Furthermore, the samples were analysed for their drug-encapsulation efficiency using UV-visible spectrophotometry. Among all three samples, the NPs synthesised using black pepper exhibited the maximum encapsulation efficiency. The study concludes that the plant's bio-profile is responsible for bringing about changes in the traits of the resulting nanoparticles. Thus, the extracts from different plants have the ability to manipulate the properties of the synthesized NPs. These findings can help to understand the role and importance of the plants in synthesizing NPs for biomedical applications. A further detailed study in this field can help researchers to understand the influence of the plant's biochemistry in shaping the NPs.

Advances in Versatile Nanoscale Catalyst for the Reductive Catalytic Fractionation of Lignin

In the past five years, biomass-derived biofuels and biochemicals were widely studied both in academia and industry as promising alternatives to petroleum. In this Review, the latest progress of the synthesis and fabrication of porous nanocatalysts that are used in catalytic transformations involving hydrogenolysis of lignin is reviewed in terms of their textural properties, catalytic activities, and stabilities. A particular emphasis is made with regard to the catalyst design for the hydrogenolysis of lignin and/or lignin model compounds. Furthermore, the effects of different supports on the lignin hydrogenolysis/hydrogenation are discussed in detail. Finally, the challenges and future opportunities of lignin hydrogenolysis over nanomaterial-supported catalysts are also presented.