Facile wet-chemical synthesis of differently shaped cuprous oxide particles and a thin film: Effect of catalyst morphology on the glucose sensing performance

In this work, different facile synthesis routes were developed to create cuprite-based catalyst systems for the amperometric detection of glucose, allowing us to evaluate the impact of important electrode fabrication parameters on the glucose sensing performance. Using homogenous precipitation routes based on a redox system, two differently shaped cuprite particles—skeletons and polyhedrons—could be obtained. Furthermore, a novel electroless deposition technique was introduced that does not require sensitization and activation pretreatments, allowing for the direct modification of the glassy carbon. This technique produced electrodes with dense thin film consisting of merged, octahedral cuprite crystals. Afterward, these materials were tested as potential catalysts for the electrochemical detection of glucose. While the catalyst powders obtained by precipitation required Nafion® to be attached to the electrode, the thin film synthesized using electroless plating could be realized with and without additive. Summarizing the results, it was found that Nafion® was not required to achieve glucose selectivities typically observed for cuprite catalysts. Also, the type of catalyst application (direct plating vs. ink drop coating) and the particle shape had a pronounced effect on the sensing performance. Compared to the thin film, the powder-type materials showed significantly increased electrochemical responses. The best overall performance was achieved with the polyhedral cuprite particles, resulting in a high sensitivity of 301 μA mmol−1 cm−2, a linear range up to 298 μmol L−1 and a limit of detection of 0.144 μmol L−1.