Hydrogen peroxide disproportionation: time-resolved optical measurements of spectra, scattering and imaging combined with correlation analysis and simulations

We study how time-dependent optical measurements of spectra, scattering, and imaging can be used to add to the understanding of heterogeneous reactions, compared to work performed using tools developed for homogeneous reactions. Using hydrogen peroxide disproportionation by potassium permanganate as a model reaction, we measure the entire spectrum over reaction time, enabling a clear and useful correlation analysis and assignment of chemical species in heterogeneous conditions. We measure time-dependent dynamic light scattering to study oxygen nanobubble product formation kinetics and equilibrium. We perform macroscopic video-rate reaction imaging and information-theoretic analysis to characterize reaction and transport contributions to the observed signal. To illustrate the differences arising from measuring sample subsets vs the entire system, we integrate stochastic and macroscopic numerical simulations of reaction-diffusion to study homogeneous and heterogeneous reaction conditions. We hope the tools presented here may help understanding other chemical reactions in similar conditions. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study investigates the application of time-dependent optical measurements of spectra, scattering, and imaging in understanding heterogeneous reactions compared to homogeneous reactions. Using the disproportionation of hydrogen peroxide by potassium permanganate as a model reaction, the entire spectrum is measured over the reaction time, allowing for clear correlation analysis and identification of chemical species in heterogeneous conditions. Time-dependent dynamic light scattering is employed to study the kinetics and equilibrium of oxygen nanobubble product formation. Macroscopic video-rate reaction imaging and information-theoretic analysis are performed to characterize the contributions of reaction and transport to the observed signal. The differences between measuring sample subsets and the entire system are illustrated through stochastic and macroscopic numerical simulations of reaction-diffusion for homogeneous and heterogeneous reaction conditions. The tools presented in this study may aid in understanding other chemical reactions under similar conditions.