(630f) Probing Surface-Adsorbate Interactions and Energetics through Active Particle Dynamics
AIChE Annual Meeting
2021
2021 Annual Meeting
Catalysis and Reaction Engineering Division
Catalysis in Liquid Media II
Thursday, November 11, 2021 - 5:00pm to 5:18pm
Active particles with Janus Pt catalyst architecture were synthesized. The particles were incubated with varying adsorbate concentrations and the MSD and drift velocity of the particles at each condition was used to construct adsorption isotherms.
Thioglycerol rapidly saturated the Pt surface and full coverage was achieved at 2 mM. Furfural, however, did not fully block H2O2 access to the surface and saturation instead resulted in a maximum coverage of ~60%. Ethanol (at much higher concentrations) similarly saturated at less than half coverage. Each adsorbate coverage plot was fitted to a Langmuir adsorption isotherm and the maximum coverage (θmax) the surface affinity of each adsorbate (Ka) were extracted. The affinity of thioglycerol towards the surface was the highest, followed by furfural and then ethanol (Ka 16.6±4.3, 0.47±0.04, and 0.0011±1e-4, respectively). Interestingly, the extracted maximum coverage appeared to trend with the affinity of each adsorbate. Moreover, measured isotherms at different temperatures allowed for extraction of the adsorption enthalpy for furfural and ethanol (âÎH: 81 and 20 kJ/mol, respectively) onto the Pt surface.
Adsorption of solute molecules onto metal surfaces has important implications in catalysis and this work shows that important parameters of this process can be captured using active particles. This approach is particularly attractive as it helps capture one of the most salient aspects of catalysis, i.e., the competitive in situ interactions of the adsorbate, peroxide, and metal surface under steady state reaction conditions in an aqueous phase.