Room-temperature fabrication of a heterostructure Cu2O@CuO nanosheet electrocatalyst for non-enzymatic detection of glucose and H2O2

Abstract

• Binder-free Cu 2 O@CuO nanosheets were deposited on FTO using vacuum kinetic spray at room temperature. • Cu 2 O@CuO nanosheets exhibited high sensitivity toward detection of glucose at 818.5 μA·mM −1 ·cm −2 . • Cu 2 O@CuO nanosheets exhibited wide linear detection range of glucose from 0.02 to 5 mM. Heterostructure Cu 2 O@CuO nanosheets are spontaneously formed during the kinetic-spraying of nanostructured CuO thin film on the fluorine-doped tin oxide (FTO) substrate at room temperature under low vacuum conditions by the NPDS technique. The Cu 2 O@CuO nanosheets fabricated as a heterogeneous electrocatalyst are utilized for free enzyme detection of glucose and H 2 O 2 in 0.1 M NaOH, whereby the synergy between the multivalent copper species (I and II) results in an overall improvement of electrocatalytic performance. The in-situ formation of interfacial Cu 2 O@CuO heterostructure is verified using a high-resolution transmission microscope and X-ray photon electron spectroscopy. The fabricated electrocatalysts exhibit high sensitivity toward glucose oxidation of 818.5 μA·mM −1 ·cm −2 with a wide linear detection range extending from 0.02 to 5 mM and a limit of detection (LOD) of 5.8 μM. Also, the heterostructure Cu 2 O@CuO nanosheets show a very wide linear detection range of H 2 O 2 oxidation from 0.02 to 11 mM with a good detection sensitivity of 168 μA·mM −1 ·cm −2 and a LOD of 8.75 μM. The long-term stability for around 30 min and high oxidation selectivity with other interfering species are verified. Furthermore, Cu 2 O@CuO nanosheets exhibit higher catalytic rate constant and diffusion coefficient toward glucose species compared with H 2 O 2 .