Grain boundary enriched CuO nanobundle for efficient non-invasive glucose sensors/fuel cells

Glucose oxidation reaction (GOR) plays a significant role in glucose fuel cells anode and glucose sensors. Therefore, optimizing the GOR catalyst nanostructure is auxiliary to their efficient operation. In this study, we present a cascade-assembled strategy to prepare CuO nanobundles (CuO-NB) with high-density and homogenous grain   boundaries (GBs). The essence of activity in GOR that depended on GBs are thoroughly investigated. The increased glucose diffusion coefficient of CuO-NB means that GBs has a faster glucose mass transfer, which is attributed to the terraces in GBs dislocation surface. Furthermore, the accumulation of electrons on GBs makes the glucose adsorption increased and the free energy of dehydrogenation step decreased, leading to a lower glucose oxidation barrier. Therefore, CuO-NB is appropriate for non-invasive glucose detection and glucose fuel cells. This study sheds new light on the GBs effect in GOR and paves the way for developing high-efficiency electrocatalysts.