A Model of Hydrogen Desorption Kinetics Controlled both by Interface and Surface Reactions for Metal Hydrides

TL;DR

This paper develops a kinetic model for hydrogen desorption in metal hydrides considering both interface and surface reactions, revealing how finite decomposition rates influence desorption behavior and particle size dependence.

Contribution

It introduces a combined interface- and surface-controlled desorption model, extending the traditional shrinking core approach with analytical insights.

Findings

Finite decomposition rate alters desorption kinetics slope.

Desorption time scales with particle size similarly to surface-controlled models.

Analytical model clarifies the role of interface reactions in hydrogen release.

Abstract

The desorption kinetics was modelled with the both interface- and surface reactions as rate-controlling steps. It has been shown analytically, that in the model of 'shrinking core' desorption, the finite hydride-decomposition-rate causes a modified slope of kinetics. The dependence of desorption time on the powder particle size has the same power of order as for the surface controlled desorption.