A Pt/SnO2/rGO interface more capable of converting ethanol to CO2 in ethanol electro-oxidation: a detailed experimental/DFT study

Abstract

In this study, we developed hierarchically structured Pt/SnO₂/rGO electrocatalysts through a “layer-by-layer” synthetic strategy. Particularly, a morphologically controlled synthesis was adopted to obtain regularly shaped SnO₂ crystallites comprising the specific facets of (101), (110), (111), and (221). Then the Pt nanoparticles of ca. 3 nm were uniformly deposited onto the different facets of SnO₂ to establish the unique Pt/SnO₂(abc) interfaces. Finally, by anchoring the graphene sheets onto the Pt/SnO₂(abc) interfaces, we accomplished hierarchically structured Pt/SnO₂/rGO electrocatalysts for ethanol electro-oxidation, allowing intensive modification of the Pt/SnO₂ interface by rGO with significant enhancement of electronic conductivity and durability. More importantly, the clear structural feature of the Pt/SnO₂ interface makes it possible to elucidate how the distinct interfacial structure will determine the efficiency, particularly the specific reaction pathways, to achieve the ultimate aim of maximizing energy efficiency. Through the detailed DFT calculations, new evidence on the SnO₂ facet-related mechanism has been identified. This is the first example both experimentally and theoretically demonstrating the significance of the Pt/SnO₂ interface to control the overall activity and in particular, the dominant route in complete/incomplete oxidation for electrocatalytic ethanol oxidation. Even without the presence of Rh in our case, the specific Pt/SnO₂/rGO system with interfacial engineering can effectively enhance the electro-oxidation of ethanol to CO₂ and energy efficiency.