Title:    Catalysis in Particle-Stabilized Liquid Foams and Plastrons

Time:     2025-07-02 10:30

Lecturer:  Prof. Marc Pera-Titus

Cardiff University

Venue:    Room 202, Lu-Jiaxi Building

Abstract：

Gas-Liquid-Solid (G-L-S) catalytic reactions are ubiquitous in the chemical industry and environmental chemistry. The efficacy of these reactions is restricted by the low gas solubility in liquids and poor mass transfer of reactants/products to/from the catalyst surface due to the physical separation of the phases. Surfactants, co-solvents, high temperatures, and pressures are required to promote the gas-liquid-solid contact. However, these adversely affect the carbon footprint of the processes.

In this talk, I will first present a taxonomy of microstructured G-L-(S) interfaces to build microreactors (catalytic membrane contactors, microdroplets, micromarbles, microbubbles and particle-stabilized bubbles/foams), including Contact Electrocatalysis (CEC), that can accelerate G-L-S reactions. Within this taxonomy, I will provide a critical appraisal of surface-active catalytic particles to engineer particle-stabilized aqueous and oil foams. I will address the fundamental thermodynamics and dynamics aspects of particle adsorption at the G-L interface and examine foaming stabilization mechanisms. I will enumerate all possible interactions between particles and G-L interfaces and elucidate how the rational design of surfaceactive particles can assist their interfacial self-assembly and generate foams in a diversity of aqueous and solvents/reactants with different polarities and interfacial tensions. This includes amphiphilic catalysts based on Janus architectures with asymmetric wettability, and assemblies of two different surface-active particles favoring dispersion and adsorption at the G-L interface.

Based on these developments, I will show current developments of light-driven interfacial heaters based on foams relying on interfacial assemblies of catalytic and plasmonic surface-active particles. These smart microreactors promote localized heating near the catalytic centers allowing operation at near-room temperature while decreasing the required energy for operation by 50% compared to thermally heated reactions at isoconversion. I will also show examples of surface-active particles for the photosynthesis of H2O2 in aqueous foam and the electrosynthesis of formic acid from CO2 in the presence of CO2 foam and plastrons.