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 system and the human body. Efficient photocatalytic reduction of Cr(VI) to Cr(III) using high-performance materials offers a viable approach for chromium decontamination. In the current work, the defective UiO-66-(OH)2 with enhanced photocatalytic activity was developed by the plasma treatment. These defects not only triggered an expansion in mesoporous domains and increased the 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 at 20 Pa, and a 300-second treatment period, UiO-66-(OH)2 exhibited a removal efficiency of 83 %. This work explored a novel way for the construction of the defective MOFs and broadened the utilizationation of MOFs in the fields of photoreduction of heavy metal ions in water.