Plasma modification of UiO-66-(OH)₂ metal organic frameworks for photocatalytic Cr(VI) reduction

Cr(VI), a hazardous heavy-metal pollutant found in wastewater, exerts detrimental effects on biological systems and the human body. Efficient photocatalytic reduction of Cr(VI) to Cr(III) using high-performance materials offers a viable approach for Cr decontamination. In the current work, defective UiO-66-(OH)₂ with enhanced photocatalytic activity was developed by plasma treatment. These defects not only triggered an expansion in mesoporous domains and increased the Brunner-Emmet-Teller (BET) surface area of the UiO-66-(OH)₂ system, thereby exposing more adsorption and photocatalytically active sites, but also created additional electron migration pathways, enhancing the separation of photogenerated e⁻/h⁺ pairs. When subjected to an operating power of 15 W, chamber pressure of 20 Pa, and a 300 s treatment period, UiO-66-(OH)₂ exhibited a removal efficiency of 83%. This work explored a novel means of construction of a defective metal organic framework (MOF) and broadened the utilization of MOFs in the fields of the photoreduction of heavy-metal ions in water.