(427f) Achieving Complete Electrooxidation of Ethanol By Single Atomic Rh Decoration of Pt Nanocubes
AIChE Annual Meeting
Wednesday, November 16, 2022 - 9:28am to 9:49am
Direct ethanol fuel cells are attracting growing attention as portable power sources due to their advantages such as higher mass-energy density than hydrogen and less toxicity than methanol. However, it is challenging to achieve the complete electrooxidation to generate 12 electrons per ethanol, resulting in a low fuel utilization efficiency. Herein, we report unalloyed single atomic, partially oxidized Rh on the Pt nanocube (NCs) surface as the electrocatalyst (RhatO-Pt NCs) to completely oxidize ethanol to CO2 at a record-low potential of 0.35 V. Pt NCs decorated with partially oxidized Rh clusters (RhclO-Pt NCs), Pt NCs, and commercial Pt/C were also prepared for comparison. The catalyst prepared after loading RhatO-Pt NCs on a carbon support (RhatO-Pt NCs/C) demonstrated the highest EOR activity among all prepared electrocatalysts. At 0.75 V (versus reversible hydrogen electrode [RHE]), RhatO-Pt NCs/C showed 1.5-, 4.2-, and 11.4-fold higher current density than those of RhclO-Pt NCs/C, Pt NCs/C, and commercial Pt/C, respectively. Most importantly, the decoration of isolated RhatO rendered the RhatO-Pt NCs/C electrocatalyst capable to break the CâC bond of ethanol, resulting in >99.9% of CO2 selectivity in a record-low onset and wide potential region (0.35 to 0.75 V). In situ X-ray absorption fine structure measurements and density functional theory calculations reveal that the single-atom Rh sites facilitate the CâC bond cleavage and the removal of the *CO intermediates. This work not only reveals the fundamental role of unalloyed, partially oxidized SAC in ethanol oxidation reaction but also offers a unique single-atom approach using low-coordination active sites on shape-controlled nanocatalysts to tune the activity and selectivity toward complicated catalytic reactions.