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Why Could the Nature of Surface Facets Lead to Differences in the Activity and Stability of Cu2O‑Based Electrocatalytic Sensors?

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journal contribution
posted on 04.06.2018 by Fabián A. C. Pastrián, Anderson G. M. da Silva, André H. B. Dourado, Ana P. de Lima Batista, Antonio G. S. de Oliveira-Filho, Jhon Quiroz, Daniela C. de Oliveira, Pedro H. C. Camargo, Susana I. Córdoba de Torresi
By a combination of theoretical and experimental design, we unraveled the effect of {111} and {100} surface facets on the electrocatalytic sensing activities and stabilities of metal oxides by employing Cu2O crystals as a model substrate and glucose as the analyte. We started by theoretically investigating the potential energy curves for the glucose interaction with the Cu2O {111} and {100} surface facets. We found that the glucose interaction energy was significantly higher for the {100} facets than for the {111} facets. Then, we experimentally observed that their electrocatalytic sensing performance displayed shape-dependent behavior. While the catalytic activities followed the order cubes > cuboctahedrons > octahedrons, their stabilities showed the opposite trend. The higher catalytic activity enabled by the {100} facets is explained by their stronger interaction with glucose. On the other hand, the higher stability allowed by the {111} facets is justified by their lower concentration of oxygen vacancies and weaker interaction with O2 relative to those of the {100} surface.