Tailoring the Acidity of Liquid Media with Ionizing Radiation -- Rethinking the Acid-Base Correlation Beyond pH

TL;DR

This paper demonstrates that ionizing radiation alters the traditional understanding of acidity in liquid media, decoupling pH from actual acidity and enabling its control through radiation dose and additives.

Contribution

It introduces a new perspective on acidity under irradiation, showing pH is insufficient and proposing radiolysis simulations for better understanding and control.

Findings

Ionizing radiation decouples acidity from autoprotolysis.

pH alone cannot describe acidity under irradiation.

Acidity can be tailored by dose rate and additives.

Abstract

Advanced in situ techniques based on electrons and X-rays are increasingly used to gain insights into fundamental materials dynamics in liquid media. Yet, ionizing radiation changes the solution chemistry. In this work, we show that ionizing radiation decouples the acidity from autoprotolysis. Consequently, pH is insufficient to capture the acidity of water-based systems under irradiation. Via radiolysis simulations, we provide a more conclusive description of the acid-base interplay. Finally, we demonstrate that acidity can be tailored by adjusting the dose rate and adding pH-irrelevant species. This opens up a huge parameter landscape for studies involving ionizing radiation.