Fe single atom post-synthetic modification of DUT-67 for highly efficient photocatalytic reduction of Cr(VI)

As Cr(VI) pollution intensifies, the development of efficient, eco-friendly, and sustainable treatment technologies has become a vital focus in environmental science. Photocatalytic reduction is often seen as a promising approach for removing Cr(VI), thanks to its low energy requirements and minimal environmental impact. However, traditional photocatalytic materials face significant challenges, including narrow photoresponse range and high rate of electron-hole recombination, which impede their practical efficiency. In this study, we successfully synthesized Fe-DUT-67 photocatalysts by incorporating Fe single atoms into the zirconium-based metal–organic framework (DUT-67) through post-synthetic modification. A significant enhancement in both the visible-light absorption capacity and carrier separation efficiency of the as-prepared Fe-DUT-67 has been observed, attributed to the formation of Fe-O coordination bonds between the Fe atoms and Zr-O clusters. Fe-DUT-67-2 exhibited impressive Cr(VI) reduction activity under full-spectrum illumination, with a remarkable 90% reduction efficiency of Cr(VI) within 18 min. Density functional theory (DFT) calculations shed light on the crucial role of Fe sites in promoting photoelectron transport and facilitating Cr(VI) reduction. This work not only presents an efficient photocatalytic material for alleviating Cr(VI) pollution but also provides a theoretical foundation and design principles for the development of high-performance catalytic systems utilizing single-atom modified metal–organic frameworks.