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Solvent evaporation and leakage of liquid electrolytes that restrict the practicality of dye-sensitized solar cells (DSSCs) motivate the quest for the development of stable and ionic conductive electrolyte. Gel polymer electrolyte (GPE) fits the criteria, but it still suffers from low efficiency due to insufficient segmental motion within the electrolytes. Therefore, incorporating metal oxide nanofiller is one of the approaches to enhance the performance of electrolytes due to the presence of cross-linking centers that can be coordinated with the polymer segments. In this research, polymer composite gel electrolytes (PCGEs) employing poly (vinyl butyral-co-vinyl alcohol-co-vinyl acetate) (P(VB-co-VA-co-VAc)) terpolymer as host polymer, tetrapropylammonium iodide (TPAI) as dopant salt, and copper oxide (CuO) nanoparticles as the nanofillers were produced. The CuO nanofillers were synthesized by sonochemical method and subsequently calcined at different temperatures (i.e., 200, 350, and 500 °C), denoted as CuO-200, CuO-350, and CuO-500, respectively. All CuO nanoparticles have different shapes and sizes that are connected in a chain which impact the amorphous phase and the roughness of the surface, proven by the structural and the morphological analyses. It was found that the PCGE consisting of CuO-350 exhibited the highest ionic conductivity of 2.54 mS cm−1 and apparent diffusion coefficient of triiodide of 1.537 × 10−4 cm2 s−1. The enhancement in the electrochemical performance of the PCGEs is correlated with the change in shape (rod to sphere) and size of CuO particles which disrupted the structural order of the polymer chain, facilitating the redox couple transportation. Additionally, a DSSC was fabricated and achieved the highest power conversion efficiency of 7.05% with JSC of 22.1 mA cm−2, VOC of 0.61 V, and FF of 52.4%. [ABSTRACT FROM AUTHOR]

Among chemical water pollutants, Cr(VI) is a highly toxic heavy metal; solar photocatalysis is a cost-effective method to reduce Cr(VI) to innocuous Cr(III). In this research work, an efficient and economically feasible ZnO/CuO nanocomposite was grafted onto the polyester fabric ZnO/CuO/PF through the SILAR method. Characterization by SEM, EDX, XRD, and DRS confirmed the successful grafting of highly crystalline, solar active nanoflakes of ZnO/CuO nanocomposite onto the polyester fabric. The grafting of the ZnO/CuO nanocomposite was confirmed by FTIR analysis of the ZnO/CuO/PF membrane. A solar photocatalytic reduction reaction of Cr(VI) was carried out by ZnO/CuO/PF under natural sunlight (solar flux 5–6 kW h/m2). The response surface methodology was employed to determine the interactive effect of three reaction variables: initial concentration of Cr(VI), pH, and solar irradiation time. According to UV/Vis spectrophotometry, 97% of chromium was removed from wastewater in acidic conditions after four hours of sunlight irradiation. ZnO/CuO/PF demonstrated reusability for 11 batches of wastewater under natural sunlight. Evaluation of Cr(VI) reduction was also executed by complexation of Cr(VI) and Cr(III) with 1, 5-diphenylcarbazide. The total percentage removal of Cr after solar photocatalysis was carried out by AAS of the wastewater sample. The ZnO/CuO/PF enhanced the reduction of Cr(VI) metal from wastewater remarkably. [ABSTRACT FROM AUTHOR]