Photocatalytic activity and mechanism of YMnO3/NiO photocatalyst for the degradation of oil and gas field wastewater

Abstract

One-step hydrothermal method has been used to synthesize YMnO3@NiO (YMO@NO) photocatalysts with high photocatalytic activity for the degradation of oil and gas field wastewater under simulated solar irradiation. Through various characterization methods, it has been confirmed that the YMO@NO photocatalyst comprises only YMO and NO, without any other impurities. The microstructure characterization confirmed that the YMO@NO photocatalyst was composed of large squares and fine particles, and heterojunction was formed at the interface of YMO and NO. The optical properties confirm that the YMO@NO photocatalyst has high UV-vis optical absorption coefficient, suggesting that it has high UV-vis photocatalytic activity. Taking oil and gas field wastewater as degradation object, YMO@NO photocatalyst showed the highest photocatalytic activity (98%) when the catalyst content was 1.5 g/L, the mass percentage of NO was 3%, and the irradiation time was 60 min. Capture and stability experiments confirm that the YMO@NO photocatalyst is recyclable and electrons, holes, hydroxyl radicals and superoxide radicals play major roles in the photocatalysis process. Based on experiments and theoretical calculations, a reasonable photocatalytic mechanism of the YMO@NO photocatalyst is proposed.

Synthesis and full-spectrum-responsive photocatalytic activity from UV/Vis to near-infrared region of S-O decorated YMnO3 nanoparticles for photocatalytic degradation of ibuprofen

“…For all samples, four obvious characteristic peaks at 3,453, 1,645, 627, and 468 cm −1 can be observed. The peaks at 3,453 and 1,645 cm −1 can be assigned to the stretching vibration of O-H and the bending vibration of H-O-H of absorbed water, respectively ( Wu et al, 2019 ; Zhang et al, 2022 ; Dang et al, 2024 ; Zhu et al, 2024 ). The presence of adsorbed water is mainly due to the absorption of water by the sample during storage and the use of potassium bromide during testing.…”

“…However, why •OH and •O 2 − play different roles in different samples during the experiment needs to be explored in detail in combination with the band theory. According to the band theory, the conduction band potential ( E CB ) and valence band potential ( E VB ) of YMO are calculated on the basis of Eqs 13, 14 ( You et al, 2020 ; Dang et al, 2024 ; Zhu et al, 2024 ). …”