Sputtered nanocrystalline samarium doped CuO photoelectrode for efficient photoelectrochemical water splitting

Abstract

Copper oxide (CuO) is a promising photoelectrode for photoelectrochemical (PEC) energy generation because of its fascinating properties, including high earth availability and inexpensive. In this context, samarium (Sm)-doped CuO thin films are deposited on a glass substrate through the sputtering technique to serve as photocatalysts in PEC water splitting. The structural characterizations of sputtered films were performed with X-ray diffraction (XRD) spectroscopy, while the morphology and elemental composition of all films were studied with the help of field-emission scanning electron microscopy (FE-SEM) connected with a dispersive energy X-ray analyzer. XRD pattern has shown that all films are polycrystalline with a preferred orientation of (−111) crystallographic plane. FE-SEM images and ImageJ analysis showed that all deposited particles are uniformly distributed as disassembled particles over the substrate area. The optical energy band gap (Eg) was increased by adding the Sm contents in the CuO films. The photocurrent density for the photoelectrode was improved by Sm dopants as compared to the pure sample and recorded its maximum value of − 4.66 mA/cm2 at ∼ − 0.385 V vs. RHE which was about 4 times higher than that of the pure sample with feasible photostability retention. Additionally, the value of the charge transfer resistor for the CuO photocathode with the smallest amount of Sm ions was the lowest as compared to other photocathodes. These results offer a practical method for creating a brand-new fabrication technique for PEC devices with remarkable water-splitting efficiency.