In situ grown indium-based MOF reticular materials on a copper mesh for highly efficient photocatalytic reduction of Cr(vi) in wastewater†

Photocatalytic technology has been regarded as a promising and valuable method for water treatment owing to its safety, efficiency, and eco-friendliness. However, its practical applications are hindered by challenges such as material aggregation and difficulties in recycling and separation, especially with powder-based catalysts. This study introduces a novel photocatalyst (MIL-68(In)-NH₂/Cu), synthesized through the in situ growth of an In-based MOF on a copper mesh, where the copper mesh serves as both a carrier for MIL-68(In)-NH₂ and forms a heterojunction with it. MIL-68(In)-NH₂/Cu exhibited a high specific surface area and a band-gap energy of 2.66 eV, achieving an impressive Cr(VI) reduction efficiency of 98.28%. Mechanistic investigations revealed that the photocatalytic reduction of Cr(VI) relied on the ˙O₂⁻ radical and the efficient transfer of photogenerated electrons. Importantly, MIL-68(In)-NH₂/Cu demonstrated superior recyclability and sustained high reduction efficiency for Cr(VI), suggesting its potential as an effective solution for Cr(VI) reduction in water treatment applications.