Session: Inorganic Catalysts:

Proton adsorption is a key elementary step in promising electrochemical reactions such as hydrogen evolution, CO₂ reduction, and ammonia synthesis. Electrocatalyst that are able to promote such reactions selectively should provide favorable adsorption sites which can stabilize reaction intermediates and promote favorable charge transfer kinetics. In this work, we evaluate the effect of tuning the surface electronic structure by changing chalcogen composition in Chevrel Phases chalcogenides Mo₆X₈ (X=S, Se, Te). These binary chalcogenides were synthesized successfully via microwave-assisted synthesis and their ability to stabilize proton adsorption was studied under relevant conditions for hydrogen production in acidic media. Electrochemical characterization shows that increasing the electronegativity of the chalcogen increases the hydrogen adsorption strength owing to an increase in the Lewis basicity of the chalcogen. The activity of Mo₆S₈ is further enhanced by decreasing particle size to the nanometer scale using a templated growth approach. The well-defined cubic shape obtained by this method provides a higher abundance of weakly coordinated surface adsorption sites and reduces the charge transfer resistance for proton reduction compared to bulk Mo₆S₈. The results presented herein provide materials design principles to improve proton adsorption in metal chalcogenide systems and increase selectivity in various electrochemical reactions.

Joseph Perryman

Appearances