Sunlight-driven photocatalytic degradation of organic dyes using Cu(i) coordination polymers: an efficient and recyclable solution for wastewater remediation†

Industrial wastewater containing organic dye pollutants poses significant environmental challenges, necessitating cost-effective and eco-friendly solutions. Coordination polymers (CPs), with their structural regularity and stability, present a promising approach for efficient solar-driven photodegradation of such contaminants. Herein we report two new 1D-Cu(I) coordination polymers, namely [Cu₂(μ₂-I)₂(μ₂-DTP)₂]_nCP1 and [Cu₂(μ₂-Br)₂(μ₂-DTP)₂]_nCP2 achieved from the self-assembly of 3-(1,3-dithian-2-yl)pyridine (DTP) ligand with CuI and CuBr, respectively. The polymeric chain in both CPs consists of a Cu₂X₂ secondary building unit. Both CPs display excellent photocatalytic efficiency in degrading organic dyes under sunlight using a minimal amount of catalyst and H₂O₂. CP1 surpassed CP2 in performance due to its narrower energy band gap, achieving an impressive 96% degradation of methylene blue (MB) within 15 minutes. The mechanism of the dye degradation was established by several experiments, including XPS analysis, which suggests the involvement of a Fenton-like Cu(I)/Cu(II) redox cycle during the photocatalytic process. The exceptional photocatalytic properties, recyclability and facile synthesis of these CPs underscore their potential for practical environmental remediation applications.