Multifunctional Cu–TiO2 porous nano-structures via post-synthesis LASER treatment for boosting energy storage and photocatalytic applications

Abstract

In this work, copper-doped titanium dioxide (Cu–TiO₂) porous nanostructures (CTPNs) are synthesized by a single-step Sol-gel technique followed by a post-synthesis LASER treatment and investigated their photocatalytic as well as electrochemical properties. The CTPNs exhibit a pure anatase phase, confirmed by X-ray diffraction (XRD), and their crystallite size has been drastically reduced from 38.43 to 16.38 nm. SEM analysis shows that pure TiO₂ has irregular grains with interconnected pores, while the 0.5 % CTPNs sample features a highly porous, finely rough surface with bright spots, indicating Cu incorporation in the TiO₂ matrix. The elemental composition of the synthesized CTPNs was confirmed through EDX spectroscopy. Furthermore, UV spectroscopy analysis indicated that with increasing Cu concentration in the TiO₂, the optical band gap shrinks from 3.24 to 2.62 eV. The photocatalytic activity measurements showed that the addition of CTPNs increased methylene blue (MB) photodegradation by 35.7 % compared to 9.6 % for pure TiO₂ as exposed to direct sunshine. Additionally, the electrochemical performance of the CTPNs-based electrodes for supercapacitors was validated through cyclic voltammetry. The 0.5 % CTPNs electrode demonstrated an enhanced specific capacitance of 279 F g⁻¹, in contrast to the 17 F g⁻¹ observed for pure TiO₂. Furthermore, the 0.5 % CTPNs exhibited an impressive energy density of 24.67 W h Kg⁻¹ at an operating voltage of 0–0.8 V for 1 M KOH. The exceptional performance of the CTPNs electrode has been justified by the incorporation of strong electrical conductivity of Cu, in the TiO₂ lattice.