Research
Plastic Upcycling
About 50 % of plastics are used as single-use packaging, which are primarily made up of low recycling rate polyolefins, e.g., LDPE (Low Density Polyethylene, #4 plastic), PP (Polypropylene, #5 plastic), PS (Polystyrene, #6 plastic), etc. Currently, the majority of these single-use plastics end up in landfills or the environment, harming the ecosystem and the natural environment. This not only wastes energy and value, but also degrades the natural environment. In this research, microwave catalytic technology is developed for upcycling plastic waste into high value chemicals (e.g., olefines and aromatics) to achieve chemical substitution. The catalyst particles play two roles simultaneously during plastic upcycling process. One is the efficient transfer of microwave electromagnetic energy into thermal heat. The other is the catalytic function that enables reactions to occur when the catalyst particles reach the necessary temperature. Heat is therefore generated selectively at the catalyst and subsequently transferred to the plastic (reactant). Hence the catalytic process takes place only at the interface between the hot (and almost certainly constantly heating) catalyst particles and the initially cold plastic, enabling the cleavage of C–C bonds of plastics.
Nature gas and CO 2 Utilization
Natural gas is a promising feedstock for fundamental chemicals (e.g., light olefines and aromatics) production. In this research, the microwave catalytic ethane CO 2 oxidative dehydrogenation (ODH) process was developed for ethylene and BTX aromatics (Benzene, Toluene, and Xylene) production. Compared with the direct dehydrogenation of ethane, CO 2 oxidative dehydrogenation is a promising route to produce ethylene while converting CO 2, a main greenhouse gas, to CO. Microwave catalytic processing demonstrated benefits in reducing the reaction temperature and improving the product selectivity.
Clean Energy
Ammonia is considered as the alternative carbon neutral fuel and hydrogen carrier due to its high energy storage capacity. The current ammonia production using the Haber-Bosch process is at high temperatures (400–520 ℃ ) and high pressures (150–300 bar). This process is capital and energy intensive, consuming more than 2% of world energy production. In this research, microwave catalytic ammonia synthesis system is developed to alternate the energy-intensive Haber-Bosch process.
Lignin has been recognized as a potential feedstock to provide aromatic hydrocarbons due to intrinsic nature poly-aromatic structure. The use of lignin as a price-competitive source of alternative jet fuel will help meet growing worldwide demand for renewable fuels and chemicals, while allowing& the aviation industry to achieve carbon-neutral growth. In this research, an energy efficient lignin pyrolysis method is developed. Through microwave catalytic pyrolysis, the lignin is depolymerized at lower reaction temperature (<300 ◦C). Moreover, pyrolysis oil is stabilized through in situ deoxygenation upgrading, reduced energy consumption in bio-oil condensation and re-evaporation.
Catlyst Development
Zeolites are crystalline aluminosilicates widely used as heterogeneous catalyst in different crude oil upgrading and chemical refinery processes. However, when bulky reactants/products are involved, this is often accompanied with serious diffusion problem inside zeolite crystalline and consequent pore blocking issues as micropore structure (< 2nm). In this research, the solid-state crystallization method is developed for hierarchical zeolite synthesis without meso-template. The additional mesopores in zeolite not only reduce the effect of channel blockage but also improve the utilization of active sites. Compared with conventional synthesis routes, this new solid crystallization approach simplifies zeolite production, lowers the cost, and avoids toxic liquid waste, which may greatly benefit many energy applications. Moreover, the hierarchically structured galloaluminosilicate ZSM-5, which the Al framework is replaced by Ga through in situ synthesis by solid-state crystallization method. The hierarchical zeolite catalysts exhibit superior stability and excellent catalytic performance in reactions such as lignin ethanolysis, naphthalene hydrogenation, bio-oil hydrodeoxygenation, natural gas dehydroaromatization.
CeO 2 is one of the most effective supports for active metal (e.g., Ru, Pt, and Ag) due to the reversible transformation of Ce 3+/Ce 4+ and abundant oxygen vacancies, which causes an increase of active metal surface electron density. The oxygen vacancies can also enhance the adsorption and activation of reaction molecules (e.g., N 2, C 2H6 and CO 2), and thus promote reaction rate. Moreover, the surface of CeO 2 easily forms the metal-O-Ce bonds, resulting in strongly bonded, finely dispersed metal nanoparticles to supply more active B5-type sites. In this study, the CeO 2 supported catalyst is developed and modified by promoters, e.g., CsRu/CeO 2. The developed CeO 2 catalysts demonstrated high activity and durability in Ammonia synthesis, natural gas, and CO 2 conversion.