| With the rapid development of glucose sensor devices in recent years,nanoscale noble metals are often used in sensing electrodes for new glucose sensors due to their good biocompatibility and good electrocatalytic activity towards glucose oxidation.However,the high cost limits their practical application,so how to obtain highly sensitive and low-cost sensing materials becomes the key to developing new sensing electrodes.Among the many known electrocatalytic glucose sensing electrode materials,copper oxide and hydroxide nanomaterials have attracted much attention due to their low price,diverse morphology,large specific surface area and unique catalytic activity.However,the poor electrical conductivity caused by single nanostructures limits further development in sensing electrodes,while complex composite structures have to be equipped with tedious preparation processes.Therefore,in this study,multidimensional graded micro-nano-structures of Au@Cu2O/CuO/Cu(OH)2 containing multivalent Cu(Ⅰ)/Cu(Ⅱ)were prepared by a simple one-pot wet chemical method as efficient electrocatalysts for glucose sensing,and their performance and enhancement mechanism for electrocatalytic glucose were investigated.The main studies and results are as follows:(1)The multi-structured materials combining Au@Cu2O/CuO/Cu(OH)2 micro-nanoparticles and nanowires were prepared by controlling the stirring speed and the amount of hydrazine hydrate added under a mild water bath environment with an average particle size of 181.02 nm and an average diameter of 39.25 nm for the nanowires in the samples,and the single structured Au@Cu2O nanoparticles(NPs)and Au/Cu(OH)2 nanowires(NWs)were prepared as comparison samples and used for subsequent comparative performance studies.(2)The electrochemical behaviour of Au@Cu2O/CuO/Cu(OH)2 was studied using cyclic voltammetry and amperometry..The detection limit ofAu@Cu2O/CuO/Cu(OH)2 for glucose was 0.26 μM and the sensitivity was 1024.6 μA mM-1 cm-2,which was 1.57 times that of pure Au@Cu2O NPs and 123.2 times that of pure Au/Cu(OH)2 NWs.At the same time,the catalyst showed good selectivity and stability towards glucose.The paper investigates the mechanism of Au@Cu2O/CuO/Cu(OH)2 electrocatalytic enhancement through analytical tests such as electrochemical impedance and specific surface area.(3)The electrocatalytic glucose performance of Au@Cu2O/CuO/Cu(OH)2 under simulated solar illumination.The results show that the enhanced performance of electrocatalytic glucose in the presence of light,with a 1.54-fold increased anode current at 0.6 V.The light-enhanced electrocatalytic mechanism was investigated using photoluminescence(PL)spectroscopy and transient photocurrent(TPC)tests,and the PL and TPC results indicate that Au@Cu2O/CuO/Cu(OH)2 has a low charge complexation capacity and a high charge separation capacity(4)The metal Pd was loaded onto the multidimensional graded micro-nano composite Au@Cu2O/CuO/Cu(OH)2 material by ultrasound-assisted self-reduction,and the combined particle-wire structure of the unloaded material was maintained after loading with Pd.Results of the electrocatalytic glucose performance test for Au@Cu2O/CuO/Cu(OH)2-Pd show a 1.6-fold increase in anode current at 0.6 V and a 1.16-fold increase in sensitivity in the 0.01-2 mM detection range. |
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