Narrow Results

Nano copper-based catalysts were prepared by co-precipitation method and the performance of catalytic hydrogenation for methyl 3-hydroxypropionate (MHP) to 1, 3-propanediol (1, 3-PDO) on the nano catalysts were studied under a high-pressure microcontinuum fixed-bed reactor. The effects of structure, texture, and composition of the catalysts on the catalytic performance were investigated by characterizing the catalysts with XRD, TG–DTG, SEM, and N₂ adsorption/desorption analysis technique. The results showed that addition of promoters enhanced the activity and selectivity of copper-based catalysts, which promoted the dispersion of the active components effectively and stabilized the active center of the catalysts. Especially, the copper-based catalyst of loaded P could restrain side-reaction effectively and improve selectivity obviously, the conversion of MHP and the selectivity of 1, 3-PDO could be 91.30% and reach 90.15%, respectively.

In this research, a series of catalysts based on MoSe₂ were synthesized by the hydrothermal method and used for the catalytic hydrogenation of alkali lignin for the first time. For 4wt.% NiSe₂/MoSe₂ catalyst, at 290${}^{\circ }$C, under 2MPa H₂ pressure for 1.5h, the conversion of alkali lignin and the yield of bio-oil reached 96.47% and 93.68%, respectively. In addition, the composition of the product (bio-oil) was analyzed via Fourier transform infrared (FTIR) spectrometry, gas chromatography-mass spectrometry (GC-MS) spectra, and proton nuclear magnetic resonance (¹HNMR) spectra. Finally, our study demonstrated that those MoSe₂-based composite catalysts can effectively degrade the biomass into bio-oil containing valuable chemical products.

Ag nanoparticles decorated N-doped carbon black with different Ag content was synthesized via a straightforward method. The catalysts have been conducted in the catalytic hydrogenation of nitrophenols in the presence of sodium borohydride. The results show that Ag₄/NCB possesses the highest catalytic activity for the catalytic hydrogenation of $p$-nitrophenol ($p$-NP) to $p$-aminophenol ($p$-AP). The significant enhancement in catalytic activity can be attributed to the high dispersity and smaller size of Ag nanoparticles, and remarkable synergistic effect of the combination of Ag nanoparticles and N-doped carbon black.

In this paper, we fabricated carbon-encapsulated cobalt/tricobalt tetroxide complex nanomaterials (Co/Co₃O₄@C) by a simple arc-discharged method and controlled annealing in air. Controlled annealing can solve the problem of poor hydrophilicity of materials prepared by arc-discharged method, and what’s more, a large number of Co/Co₃O₄ heterointerfaces can be constructed. Carbon-encapsulated Co/Co₃O₄ exhibited excellent catalytic performance in the catalytic hydrogenation of 4-nitrophenol (4-NP), even better than that of the reported precious metal catalysts in the literature. Excellent catalytic performance not only contributed to improved hydrophilicity, but also contributed to the synergistic effects of Co and Co₃O₄ on the catalytic 4-NP hydrogenation. The preparation process is appropriate for synthesizing various defective-rich metals or alloy@carbon electrocatalysts.

Fast pyrolysis is considered to be the simplest and most cost-effective approach to produce liquid oil (bio-oil) from biomass. Bio-oil is not suitable to substitute for petroleum as high-quality fuels and significant upgrading such as hydrotreating is required to remove oxygen, add hydrogen, and rearrange the carbon backbone of bio-oil. However, the grand challenge in bio-oil hydrotreating technology is bio-oil instability, which limits the lifetime of catalyst and operation. To enable a sustainable and economically viable process for bio-oil hydrotreating, it is vital to develop effective technologies for stabilizing bio-oils. This chapter will be devoted to bio-oil stabilization. The current understating of the major cause of bio-oil instability, condensation of reactive species such as sugar, aldehydes, ketones, and phenolics, is elucidated. The reported physical and chemical methods for bio-oil stabilization are summarized in detail, with a specific focus on bio-oil catalytic hydrogenation for stabilization. The impact of stabilization on bio-oil hydrotreating is discussed as well.

Today, fossil carbon provides us with fuels (energy), polymers (packaging, insulating and building materials, household utensils, glues, coatings, textiles, 3D-printing inks, furnitures, vehicle parts, toys, electronic and medical devices, etc.) and biologically active substances (drugs (Chapter 9), flavorings, fragrances, food additives, plant protection products, etc.). In this chapter we discover the modern materials of our civilization which are very often polymers derived from oil. They are referred to as “plastics” (annual world production: 380 × 10⁶ tons). Their production consumes 8% of the crude oil extracted (ca. 5 billion tons per year). An increasing part of the plastics originates from renewable resources (less than 10% today, see Section 11.10, bio-sourced plastics). Plastics make life easy for us, but at the underestimated cost of damage to our environment (Figure 8.1) and our health. They contaminate the hydrosphere and the agricultural soil. The atmosphere is also contaminated by microplastics…