Cu-incorporated NH2-MIL-125(Ti): a versatile visible-light-driven platform for enhanced photocatalytic H2 generation and CO2 photoconversion

Abstract

Here, we present for the first time an efficient platform for simultaneous H₂ generation and CO₂ conversion into HCOOH, utilizing a Cu-incorporated NH₂-MIL-125(Ti) material with triethanolamine as the sacrificial agent. When subjected to light, Cu–NH₂-MIL-125(Ti) exhibits a remarkable enhancement in H₂ generation, with a 30-fold increase under UV-Vis light and an 8-fold increase under visible irradiation compared to the pristine MOF. The study on the CO₂ photoreduction ability of Cu–NH₂-MIL-125(Ti) indicated successful conversion into formic acid yielding 62.4 μmol g_cat⁻¹ under visible irradiation. This notable improvement in photocatalytic activity can be attributed to the heightened light absorption capacity and efficient charge transportation and separation mechanisms inherent in Cu–NH₂-MIL-125(Ti). Furthermore, the stability of the Cu–NH₂-MIL-125(Ti) photocatalyst remains steady even after 24 hours of continuous irradiation. The theoretical simulations suggest that Cu introduction effectively reduces the bandgap while leaving the position and composition of the valence band unaffected.