The optimization of CuxO microwires synthesis for improvement in photoelectrochemical performance.

One of the most important challenges in the fabrication of Cu x O microstructures via the electrochemical method is formation of long, regular and well-packed microwires with good adhesion on the Cu substrate and to achieve better photoelectrochemical properties, which can be potentially applied in solar-driven water splitting and CO 2 conversion to light hydrocarbons. In this paper, Cu 2 O photoelectrode has been fabricated by direct anodization of the Cu foil, then CuO microwires (MWs) was formed by calcination process. The effect of the applied potential (10–40 V), sodium fluoride content in the electrolyte (0.2–0.5% wt.) as well as calcination conditions (400–500 °C, 60–360 min) on the morphology, phase composition, optical and photoelectrochemical properties was investigated. The highest photocurrent response was −0.71 mA cm−2 for the sample 0.35%_10V_400 °C_60min with 0.83 μm length and 154 nm diameter. The mechanism of the photocurrent generation process in the presence of Cu x O/Cu under UV–Vis irradiation was proposed. Thin films of CuO MWs/Cu 2 O were produced on the surface of Cu plates by anodic oxidation. A tendency of increase in the number and length of microwires was observed with the increase in NaF concentration and the increase in the voltage applied during anodization. A mechanism for the synthesis and photoexcitation of the obtained samples was also proposed. [Display omitted] • Optimization of the Cu anodization - voltage (10–40 V); NaF conc. (0.2–0.5% wt.); calcination (400–500 °C, 60–360 min). • Tendency to increase the length and number and decreasing diameter of the microwires with increasing NaF conc. and voltage. • Increasing the photocurrent response 1.65 timer comparing to calcinated pristine Cu plate. • Proposed mechanism of the photocurrent generation process in the presence of Cu x O/Cu under the UV–Vis irradiation. [ABSTRACT FROM AUTHOR]