Deposition of CeO2 on TiO2 nanorods electrode by dielectric barrier discharge plasma to enhance the photoelectrochemical performance in high chloride salt system

Abstract

• One-step deposition and synthesis of CeO 2 /TiO 2 -NRs electrode by DBD plasma. • A bond combined CeO 2 (1 1 1) with TiO 2 was formed in CeO 2 /TiO 2 -NRs electrode. • The proportion of Ce 3+ /Ce 4+ was increased by plasma modification to enhance oxygen vacancy. • Heterojunction was formed between TiO 2 and CeO 2 to have a narrower band gap. • DBD plasma promotes PEC performance of CeO 2 /TiO 2 -NRs in high chloride salt system. In this study, cerium oxide (CeO 2 ) was deposited on TiO 2 nanorods (TiO 2 -NRs) through the one-step deposition by using dielectric barrier discharge (DBD) plasma treatment, where this was a simple and efficient means of synthesizing a CeO 2 /TiO 2 -NR electrode. The results of X-ray diffraction indicated that CeO 2 (1 1 1) was successfully loaded on the TiO 2 -NRs, and the peak shifted in the positive direction after DBD discharge-induced modification, indicating that a bond between CeO 2 and TiO 2 had been formed in the CeO 2 /TiO 2 -NR electrode. Based on X-ray photoelectron spectroscopy, the ratio of Ce 3+ /Ce 4+ increased due to plasma modification to enhance the oxygen vacancy of the CeO 2 /TiO 2 -NRs in the lattice structure. The CeO 2 /TiO 2 -NR composite electrode delivered the best photoelectrochemical (PEC) performance at a modified input voltage of 45 V and a deposition time of 10 min due to DBD discharge. The efficiency of removal of phenol from simulated seawater with a high salt system yielded the highest value of 97.1% for the CeO 2 /TiO 2 -NR electrodes through the PEC process at 3 V and UV–visible irradiation. A mechanism of the PEC performance of the CeO 2 /TiO 2 -NRs electrode was proposed, whereby a heterojunction was formed between TiO 2 and CeO 2 to increase the effect of oxygen storage, and active chlorine ions were produced in the high chloride salt system to enhance the degradation of pollutants.