  The following study investigates the thermodynamic reaction barriers during
nitrogen fixation for an inorganic sulfur desorbed photocatalyst Molybdenum
disulfide surface. The design space is investigated using an density functional
theory (DFT) method within a space bound by MMoS$_2$ M=Mo,Fe,Co. The discussion
focuses on Heyrovsky type reactions along both the associative and dissociative
pathway. A key insight into the roles of the inorganic and the balance between
nitrogen and hydrogen affinity, providing evidence for an optimal material that
minimizes the required over-potential. It is found that phases with a higher
concentration of Mo face high reaction barrier involving nitrogen, where phases
with higher concentrations of Fe and Co face high reaction barriers involving
hydrogen species. In the absence of kinetic considerations, the best phase was
predicted to be the 1T phase with a Mo$_{0.75}$Fe$_{0.25}$S$_{2}$ composition.
This phase proved to have a balance of hydrogen and nitrogen affinity and
follows the dissociative pathway, which can be evolved through non-thermal
methods.
