Energy dissipation in ensembles of catalytic Janus particles

Abstract

The conversion of chemical energy into mechanical energy, which drives the motion of active particles, inherently involves energy dissipation. Dissipation plays a crucial role in transport efficiency, structure formation in self-organizing systems, and the thermodynamic properties of active particle suspensions. In this work, we present a thermodynamic analysis that derives the energy dissipation of coupled irreversible processes occurring in particles, substrate, and solvent. Dissipation in chemical reactions is examined under conditions where the reaction flux follows a nonlinear dependence on affinity, as described by the law of mass action. Our approach considers concentration-dependent reaction rates, in contrast to some previous descriptions of active particles, which assume a constant reaction rate and, consequently, a constant active velocity of the particles. We analyze entropy production for both cases, highlighting significant discrepancies and demonstrating that assuming a constant active velocity overlooks key thermodynamic contributions. Our framework provides a more accurate and self-consistent characterization of entropy production, capturing the inherent nonlinearities of active particle dynamics.