(528g) Electrocatalysis Under Cover: Enhanced Hydrogen Evolution Reaction Via Defective Graphene-Covered Pt(111)
AIChE Annual Meeting
Wednesday, November 10, 2021 - 5:00pm to 5:15pm
Initial HER currents on both pre-treated and un-treated Graphene/Pt(111) are slower than Pt(111) by 1 to 2 orders of magnitude (0.005 to 0.5 M, 23°C, -0.08 VRHE). HER currents on both pre-treated and un-treated Graphene/Pt(111) increase with HER reaction time to values equal to or higher than that of Pt(111), concurrent with increasing graphene defects as probed using CV and SEM. Unchanged HER Tafel slopes and [H+] reaction orders suggest the same HER mechanism between Pt(111) and Graphene/Pt(111). We postulate that untreated graphene is mass transfer limited and HER currents transition from mass transfer limited to kinetics limited with increasing graphene defects. Li et al. computes that a graphene overlayer would weaken the hydrogen binding energy to Pt(111), shift the reaction closer to the peak of the HER volcano plot, and thus increase HER currents [6,7]. Though our results agree with prediction, we cannot negate other possible explanations for the observed increase in HER rate. These results demonstrate the promise of overlayer and confinement modifications in designing catalysts with properties closer to achieving optimum currents.
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