Synthesis of dual-functional CuO nanotubes for high-efficiently photoelectrochemical and colorimetric sensing of H2O2.

Among one-dimensional nanostructures, copper oxide nanotubes (CuO NTs) have aroused wide attention due to their prominent performance in electronic, optical and energy conversion devices. However, the lack of suitable synthetic methods limits its large-scale production and broad application. Here, a new method for preparing well-dispersed CuO NTs with simple operation, mild conditions and low cost was established by integrating the synergy effect of H+ corrosion with the protection of CH3COO- and surfactant. Different surfactants were applied to regulate the synthetic process and polyvinylpyrrolidone-protected CuO NTs (PVP-CuO NTs) owned the best uniform morphology and dispersibility. The synthesis mechanism was deeply investigated to provide guidance for the synthesis of other oxide nanotube structures. As an excellent semiconductor material, CuO NTs can be excited to produce multiple electron-hole pairs under light irradiation, thus catalyzing the reduction of H2O2. CuO NTs modified photocathode realized photoelectrochemical sensing of H2O2 in the range of 1 μM-1 mM. Interestingly, the prepared CuO NTs exhibited wonderful mimic enzyme properties, providing the possibility of colorimetric sensing and point-of-care detection. The colorimetric sensor for H2O2 detection had a linear relationship from 2 μM to 150 μM with a detection limit of 0.62 μM. The successful construction of the two sensing modes not only demonstrated the excellent performance of multifunctional CuO NTs, but also indicated its great promise in practical application.