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Copper oxide (CuO) is a p-type semiconductor material having versatile use in a wide number of applications. In this work, a CuO nanoleaf structure has been synthesized without any traces of Cu2O by a one-step facile method under mild refluxing conditions. The phase purity of the sample is confirmed by x-ray diffraction, x-ray photoelectron spectroscopy, and high resolution transmission electron microscopy. Photoelectrochemical performance has been evaluated by linear scan voltammetry, and transient photocurrent has been measured in the presence of a visible light source of 350 W. Transient photocurrent shows a high photocurrent density of −6.0 mA cm−2 [at −0.2 V vs reference hydrogen electrode (RHE)] in neutral pH. The enhancement of photocurrent density is due to the large space charge region potential, confirmed by a Mott–Schottky measurement. This large space charge region potential is responsible for the higher efficiency of electron–hole separation and a concurrent increase in the kinetics of the process. [ABSTRACT FROM AUTHOR]

In this study, Bi 2 O 2 CO 3 (BSC) nanoplates with high aspect ratio and hierarchical nanostructures were prepared by hydrothermal technique using urea/hexamethylenetetramine as hydrolysing agent and KCl as additive in different solvent systems. The relative molar proportion of urea and KCl was crucial for phase purity as well as thickness and planar dimension of the BSC plates. The BSC nanoplates were used as substrates to prepare CuS-Bi 2 O 2 CO 3 (CuS/BSC) direct z-scheme heterojunction systems. The heterojunction materials were characterized by FESEM, HRTEM, XRD, PL, FTIR and UV–Vis-DRS techniques. The presence of crystalline tetragonal BSC and hexagonal covellite CuS phase was inferred from XRD study. Morphologically, the CuS/BSC material contained CuS nanorods and BSC nanoplates. HRTEM study suggested microscopic close contact between the CuS nanorods and BSC nanoplates. Optical property study revealed improvement in visible light absorption and enhanced separation of excitons. The CuS/BSC materials were used as photocatalyst for chlorpyrifos pesticide degradation under visible light irradiation. The heterojunction materials were highly active achieving >95% degradation within 3 h of reaction. The pathway and mechanism of CP degradation was elucidated using GCMS and radical scavenger experiments. [ABSTRACT FROM AUTHOR]