Waste-derived Ag@Cu-MOF with semiconductor functionalized nano-hybrid heterostructures for photocatalytic CO₂ conversion to methanol fuel

Photocatalytic reduction of carbon dioxide (CO₂) presents an inspiring strategy to mitigate climate change and produce solar fuels. Incorporating green synthesis materials into photocatalysis presents substantial promise for sustainable environmental solutions, particularly in the process of turning CO₂ to solar fuels. Green-synthesised compounds, such as copper oxide (CuO), silver (Ag), and copper-1,4-benzenedicarboxylate (CuBDC), are investigated for the photocatalytic reduction method of producing solar fuels from CO₂. Abelmoschus esculentus (Okra) was used for the synthesis of CuO, Durio zibethinus L. (Durian) rind was used for the synthesis of Ag and waste polyethylene terephthalate (PET) bottles were used for the CuBDC synthesis. CuO is grafted with reduced graphene oxide (rGO), copper −1,4-benzenedicarboxylate (CuBDC) was doped with silver nanoparticles and then combined with CuO-rGO to perform photocatalytic experiments on the newly synthesised compound of CuO-rGO/Ag-CuBDC. Chemical and structural properties of all synthesised compounds are probed by XRD, FTIR, Raman spectroscopy, XPS, TEM, SEM EDS, and UV-Vis-NIR-spectroscopy analysis, etc. CuO-rGO/Ag-CuBDC nanocomposites' photocatalytic capability is investigated for the reduction of CO₂ into methanol when exposed to LED light. CuO-rGO yielded 2.5 μmolg⁻¹catL⁻¹ of methanol and (1 %)Ag-CuBDC yielded 27.58 μmolg⁻¹catL⁻¹ of methanol whereas CuO-rGO/Ag-CuBDC showed enhanced photocatalytic activity by 12 folds of CuO-rGO and 1.1 folds of (1 %)Ag-CuBDC by yielding 30.49 μmolg⁻¹catL⁻¹ of methanol. Slow charge carrier recombination was identified as the cause of CuO-rGO/Ag-CuBDC nanocomposites improved photocatalytic activity due to doping of CuBDC with AgNPs, effective photogenerated electron transport via the covalently grafted rGO skeleton on CuO.