Depolymerization of plastics by means of electrified spatiotemporal heating

Photothermal Mediated Chemical Recycling to Monomers via Carbon Quantum Dots

“…The resulting lower reactive intermediate concentrations should reduce byproduct pathways like bimolecular reactions with oxygen (Figure a). Additionally, heat localization to the polymer material may allow for better monomer diffusion away from elevated temperatures compared to bulk heating, limiting byproduct formation …”

“…Spatially confined C–C bond cleavage should result in a lower concentration of reactive radical intermediates, limiting side reactions, such as bimolecular oxidation reactions. This concept is supported by recent work, which has shown electrically generated thermal gradients to promote the pyrolysis of select polymers to monomers with improved yield and selectivity compared to uniform heating . We hypothesized that photothermal heating could merge the advantages of photocatalysisthe temporal and spatial control over radical formationwith the generality of heat to perform challenging transformations like C–C bond cleavages in depolymerization reactions .…”

Controllable Synthesis of Solid Catalysts by High-Temperature Pulse

“…14 Notably, diffusion is a temperature-dependent fundamental process underlying high-entropy catalysts preparation. The diffusion coefficient, which is a manifestation of the microscopic motion of atoms during pulsed heating, obeys the Arrhenius formula (eq 5): ( 5) where D 0 denotes the pre-exponential factor, ΔH is the activation enthalpy, T is the absolute temperature, and k B is the Boltzmann constant. For instance, diffusion due to Brownian motion leads to the complete mixing of atoms or molecules.…”

“…High temperatures significantly alter the structures or modify the properties of all materials and, consequently, have profound implications for the controlled synthesis of solid catalysts through thermally driven solid–solid or solid–gas reactions. − The temperature window ranges from hundreds to thousands of Kelvin degrees (K) achieved through multiple technical routes, determining the fundamental processes in solid catalysts preparation, such as the activation and transformation of chemical bonds, the diffusion and collision of atoms or molecules, the nucleation and growth of nanocrystals. − Conventional near-equilibrium thermal treatment methods have heating and cooling rate that are usually less than 100 K/min. In contrast, transformative pulsed heating methods, such as laser heating, Joule heating, and microwave heating, exhibit significantly higher heating and cooling rates, typically exceeding 1000 K/s, and have been comprehensively reviewed elsewhere. − These pulsed heating methods are capable of providing a kinetics-dominant and thermodynamically nonequilibrium environment for the synthesis and processing of advanced solid catalysts.…”

Green and large‐scale production of ammonia: Laser‐driven pyrolysis of nitrogen‐enriched biomass

“…16 In addition, the catalyst-free pyrolysis of plastics to generate micromolecules through Joule heating with a heating rate of 103 • C/s was achieved. 17 As a booming technology, laser with high-energy density has been widely applied in the preparation of nanomaterials. [18][19][20] A local hightemperature field can be created on the target by laser irradiation.…”