Coverage Dependent Thermodynamics for Sulfur Poisoning of Ni Based Anodes

Abstract

We present an ab-initio thermodynamics model for sulfur poisoning of Ni. This model explicitly includes both the competitive adsorption of H2 and H2S as well as adsorbate coverage effects. Our results show that the adsorption energy for both H2S and H2 on Ni is a strong function of surface species coverage while the entropy of adsorption is weakly dependent on coverage. We outline the derivation of the coverage-dependent surface species chemical potential, use it to calculate the predicted equilibrium coverages of S and H on Ni across a wide range of industrially relevant reaction conditions, and compare our results with data in the literature.