Synthesis and characterization of nickel cobaltite–supported film for hexavalent chromium photocatalytic reduction

ABSTRACT Hexavalent chromium (Cr(VI)) is a prevalent and highly toxic pollutant, posing a serious threat to human health and ecosystems. This study addresses this issue by exploring the photocatalytic reduction of Cr(VI) using hydrothermally synthesized nickel cobaltite (NiCo2O4) spinel–supported films. The research fills the gap for efficient visible light photocatalytic materials for Cr(VI) reduction, with the aim to synthesize, characterize, and assess NiCo2O4-supported films’ photocatalytic activity. Synthesis was achieved via a hydrothermal method on fluorine-doped tin oxide (FTO) and titanium dioxide (TiO2) over FTO substrate. The films were characterized using several techniques and their photocatalytic activity was tested under UV-A and visible light, with Cr(VI) concentration monitored periodically up to 240 min. The NiCo2O4/TiO2 film demonstrated superior photoreduction performance under both UV and visible light radiation compared to TiO2 and NiCo2O4, achieving photoreduction of Cr(VI) by 76% under UV light with a rate constant of 5.79 × 10−3 min−1 and 60% under visible light with a rate constant of 4.74 × 10−3 min−1. In conclusion, hydrothermally synthesized NiCo2O4/TiO2 film shows promising photocatalytic performance for Cr(VI) reduction, marking a significant advancement in photocatalysis and water treatment technologies. Future research will focus on stability assessment, synthesis process optimization, and real-world water treatment application.