Interfacial transport for hydrogen peroxide decomposition at pt/au surfaces
Interfacial transport for hydrogen peroxide decomposition at Pt/Au surfaces
Aura Visan1*, Rob Lammertink1, Pieter Bruijnincx2
1Soft matter, fluidics and interfaces group, University of Twente
2Inorganic chemistry and catalysis group, Utrecht University
Mass transfer is always an issue in heterogeneous catalysis as reactions at liquid-solid interface involve the migration of species to the active catalytic sites. While macroscopic mixing can help in the bulk, the limiting factor lies in the boundary layer transport where concentration depletion or enrichment occurs due to the viscosity related velocity decrease towards the solid wall. The resolution could come from a surface driven flow which would impact globally the conversion capacity of the system.
Fig. 1 H2O2 decomposition on a Pt/Au Janus particle Fig. 2 Concept illustration for catalytic heterogeneity
In this project a model reaction will be studied, namely the hydrogen peroxide oxidation and reduction on Pt and Au, respectively. The proton production and consumption leads to a charge distribution which translates into a self-generated electric field which in turn enhances electro-migration. The fast kinetics combined with the self-generated electro-osmosis leads to very intense flows with vortex structures. The focus in literature for this type of system is mostly on migration of engineered particles which are propelled by the flow at the surface (Fig 1). The interest here is to observe directly the fluid dynamics and mass transfer at immobilized surfaces. The interfacial transport is studied on length scales comparable with the boundary layer using a microfluidic platform (Fig. 2). Niche analytical techniques such as µPIV and FLIM will make possible the direct visualization of velocity and concentration profiles. Both µPIV and FLIM require complex data processing giving the student the opportunity to acquire valuable skills. The challenge is to develop a 3D particle tracking protocol.
Please do not hesitate to contact Aura Visan for additional information!