Work Function Dependent Reduction of Transition Metal Nitrides (TMNs) in Hydrogen Environments

Amidst the growing importance of hydrogen in a sustainable future, it is critical to develop coatings that can protect system components in reactive hydrogen environments. However, the prediction of the chemical stability of materials in hydrogen is not fully understood. In this study, we show that the work function is a key parameter determining the reducibility (i.e., de-nitridation) of transition metal nitrides (TMNs) in hydrogen radicals (H*). We demonstrate that when the work function of a TMN drops below a threshold limit, its reduction effectively stops. This finding provides a novel perspective for comprehending the hydrogen and transition metal compounds interaction and allows predicting the chemical stability of hydrogen-protective coatings.