High effectiveness self-cleaning activity on TiO2/rGO nanocomposite synthesized by mangosteen (Garcinia mangostana L.) peel extract
Maisari Utami, Luthfia Sinta Rahmadhani, Karna Wijaya, Balasubramani Ravindran, Mir Waqas Alam, Latifah Hauli, Aditya Rianjanu, Indra Purnama, Gani Purwiandono, Salmahaminati
Abstract
• “TiO 2 /rGO was prepared using Garcinia mangostana L. peel extract. • TD-DFT computational method confirmed the effectiveness of photocatalytic process. • TiO 2 /rGO exhibited photocatalytic activity with 99.20% degradation of MB. • TiO 2 /rGO showed a promising self-cleaning material with hydrophilic characteristic. The fabrication of TiO 2 /rGO nanocomposites employing mangosteen peel extract as a bioreductor for self-cleaning applications has been successfully conducted. The research reduced graphene oxide (GO) to rGO using mangosteen peel extract as the reducing agent. TiO 2 synthesis was carried out via a biosynthesis method using mangosteen peel extract while TiO 2 /rGO nanocomposite was obtained using hydrothermal method. TiO 2 /rGO had an anatase phase with a crystal size of 10.439 nm and band gap energy of 3.04 eV which is lower than TiO 2 (3.12 eV). Moreover, TiO 2 /rGO demonstrated mesoporous characteristics with a high surface area of 95.845 m 2 /g. TEM morphology revealed TiO 2 nanoparticle spheres uniformly dispersed on rGO sheets, with 11.2 nm as the average particle size. The time-dependent density functional theory (TD-DFT) computational method showed the distance between methylene blue (MB) atoms and rGO to be 1.6 Å, with the highest oscillator strength of 0.7801, indicating a HOMO −1→LUMO +1 transition, which experiences excitation from π to π*. Photocatalytic self-cleaning tests of the TiO 2 /rGO nanocomposite on MB degradation demonstrated that irradiation with visible light produced superior photocatalytic activity compared to dark and UV light conditions, achieving a degradation percentage of 99.20%. The water contact angle of the TiO 2 /rGO material decreased from 58° before irradiation to 52° after visible light irradiation, indicating the hydrophilic characteristic and effective self-cleaning capabilities of the TiO 2 /rGO nanocomposite.