Construction of dual Z-scheme UiO-66-NH2/BiOCl/BiOI heterojunction for synergistic photocatalytic CO2 reduction and organic pollutant degradation.

To overcome the narrow visible-light response (bandgap ∼ 3.20 eV) and rapid charge recombination of bismuth oxychloride (BiOCl), a dual Z-scheme UiO-66-NH2/BiOCl/BiOI heterojunction was designed by combining a visible-active Metal organic framework (MOF, UiO-66-NH2) and narrow-bandgap bismuth iodide oxide (BiOI). Synthesized hydrothermally at an optimal Cl/I ratio (3:1), the composite exhibited extended light absorption and efficient charge separation, validated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy, and photocurrent analysis. The heterojunction achieved 34.2 μmol/g/h CO production, 91.5 % tetracycline degradation (TC) (120 min), and 98.4 % Rhodamine B (RhB) removal (60 min), surpassing single and binary systems. Mechanistic studies (radical trapping, XPS shifts) confirmed dual Z-scheme electron transfer, enabling simultaneous Carbon dioxide (CO2) reduction and pollutant degradation. This work provides a novel strategy for BiOCl-based photocatalysts, bridging environmental remediation and sustainable energy conversion.