Synergistic interaction between scrap tyre and plastics for the production of sulphur-free, light oil from fast co-pyrolysis.

Fast co-pyrolysis offers a sustainable solution for upcycling polymer waste, including scrap tyre and plastics. Previous studies primarily focused on slow heating rates, neglecting synergistic mechanisms and sulphur transformation in co-pyrolysis with tyre. This research explored fast co-pyrolysis of scrap tyre with polypropylene (PP), low-density polyethylene (LDPE), and polystyrene (PS) to understand synergistic effects and sulphur transformation mechanisms. A pronounced synergy was observed between scrap tyre and plastics, with the nature of the synergy being plastic-type dependent. Remarkably, blending 75 wt% PS or LDPE with tyre effectively eliminated sulphur-bearing compounds in the liquid product. This reduction in sulphur content can substantially mitigate the release of hazardous materials into the environment, emphasizing the environmental significance of co-pyrolysis. The synergy between PP or LDPE and tyre amplified the production of lighter hydrocarbons, while PS's interaction led to the creation of monocyclic aromatics. These findings offer insights into the intricate chemistry of scrap tyre and plastic interactions and highlight the potential of co-pyrolysis in waste management. By converting potential pollutants into valuable products, this method can significantly reduce the release of hazardous materials into the environment.

Unravelling the atomistic mechanisms underpinning the morphological evolution of Al-alloyed hematite.

Hydrothermal synthesis based upon the use of Al3+ as the dopant and/or ethanol as the solvent is effective in promoting the growth of hematite into nanoplates rich in the (001) surface, which is highly active for a broad range of catalytic applications. However, the underpinning mechanism for the flattening of hematite crystals is still poorly comprehended. To close this knowledge gap, in this work, we have attempted intensive computational modelling to construct a binary phase diagram for Fe2O3-Al2O3 under typical hydrothermal conditions, as well as to quantify the surface energy of hematite crystal upon coverage with Al3+ and ethanol molecules. An innovative coupling of density functional theory calculation, cluster expansion and Monte Carlo simulations in analogy to machine learning and prediction was attempted. Upon successful validation by experimental observation, our simulation results suggest an optimum atomic dispersion of Al3+ within hematite in cases when its concentration is below 4 at% otherwise phase separation occurs, and discrete Al2O3 nano-clusters can be preferentially formed. Computations also revealed that the adsorption of ethanol molecules alone can reduce the specific surface energy of the hematite (001) surface from 1.33 to 0.31 J m-2. The segregation of Al3+ on the (001) surface can further reduce the specific surface energy to 0.18 J m-2. Consequently, the (001) surface growth is inhibited, and it becomes dominant after the disappearance of other surfaces upon their continual growth. This work provides atomistic insights into the synergistic effect between the aluminium textural promoter and the ethanol capping agent in determining the morphology of hematite nanoparticles. The established computation approach also applies to other oxide-based catalysts in controlling their surface growth and morphology, which are critical for their catalytic applications.

High production of furfural by flash pyrolysis of C6 sugars and lignocellulose by Pd-PdO/ZnSO4 catalyst.

Furfural (C5H4O2) is an important platform chemical for the synthesis of next-generation bio-fuels. Herein, we report a novel and reusable heterogeneous catalyst, Pd-PdO/ZnSO4 with 1.1 mol% palladium (Pd), for the production of furfural by flash pyrolysis of lignocelluloses at 400 °C. For both dry and wet C6 cellulose and its monomers, the furfural yields reach 74-82 mol%, relative to 96 mol% from C5 xylan and 23-33 wt% from sugarcane bagasse and corncob. The catalyst has a well-defined structure and bifunctional property, comprising a ZnSO4 support for the dehydration and isomerization of glucose, and a local core-shell configuration for metallic Pd0 encapsulated by an oxide (PdO) layer. The PdO layer is active for the Grob fragmentation of formaldehyde (HCHO) from glucose, which is subsequently in-situ steam reformed into syn-gas (i.e. H2 and CO), whereas the Pd0 core is active in promoting the last dehydration step for the formation of furfural.

Carbonyl-bridged energetic materials: biomimetic synthesis, organic catalytic synthesis, and energetic performances.

In order to obtain high-performance energetic materials, in this work, carbonyl groups (C[double bond, length as m-dash]O) have been newly introduced as sole bridging groups in the field of energetic materials. To this end, two tailored green methods for the synthesis of carbonyl-bridged energetic compounds have been developed for the first time. One is a biomimetic synthesis, in which the conversion route of heme to biliverdin has been used to obtain metal-containing energetic compounds. The other one is an organocatalysis, in which guanidinium serves as an energetic catalyst to afford other energetic compounds. Experimental studies and theoretical calculations have shown that carbonyl-bridged energetic compounds exhibit excellent energetic properties, which is promising for the carbonyl group as a new important and effective linker in energetic materials.