Green photocatalytic conversion of CO2 to renewable fuel over Ag/Cu-TiO2/g-PAN nanofibers under solar irradiation

While semiconductor-based photocatalysis presents a promising avenue for CO 2 reduction, the application of conventional TiO 2 is restricted by its limited light absorption, short photogenerated charge carrier lifetime, and poor CO 2 adsorption capability. To overcome these constraints, we constructed multifunctional Ag/Cu-TiO 2 /graphitic-phase polyacrylonitrile (g-PAN) composites. In this system, g-PAN functions as a robust support for Ag/Cu nanoparticle-loaded TiO 2 fibers synthesized via electrospinning and heat treatment. UV–Vis NIR DRS analysis reveals synergistic light harvesting where the localized surface plasmon resonance of Ag/Cu nanoparticles extends absorption into the near-infrared and g-PAN doubles the intensity by trapping photons within nanocavities. Beyond these optical benefits, g-PAN enhances CO 2 adsorption and accelerates charge transfer. Consequently, the Ag/Cu-TiO 2 /g-PAN composite achieves a CO evolution rate of 11.82 mmol/g/h under simulated solar irradiation, representing a twice increase compared to the Ag/Cu-TiO 2 counterpart. As evidenced by Electrochemical Impedance Spectroscopy and instantaneous photocurrent response, g-PAN acts as an electronic bridge that significantly reduces the resistance to photogenerated charge migration. This study provides novel insights into designing highly efficient composite photocatalysts for sustainable CO 2 conversion, contributing to the advancement of cleaner production and green technologies.