Enhanced Photoinduced Electrocatalytic Oxidation of Methanol Using Pt Nanoparticle-Decorated TiO2-Polyaniline Ternary Nanofibers

Herein, perylene-3,4,9,10-tetracarboxylic acid-doped polyaniline (PTP) nanofibers with/without photoreactive anatase TiO2 (TiO2-PTP and PTP, respectively) have been successively synthesized and subsequently decorated by Pt nanoparticles (Pt NPs) to prepare Pt-PTP and Pt-TiO2-PTP composites. High-resolution transmission electron microscopy confirms the presence of similar to 3 nm spherical-shaped Pt NPs on both the composites along with TiO2 on Pt-TiO2-PTP. Pt loading on the composites is deliberately kept similar to compare the methanol electro-oxidation in the two composites. The Pt nanocomposites along with the precursor polyanilines are characterized by optical characterization, X-ray diffraction study, X-ray fluorescence spectroscopy, and Raman spectroscopy. The ternary composite-modified (Pt-TiO2-PTP) electrode demonstrates high electrocatalytic performance for methanol oxidation reaction in acid medium than Pt-PTP and Pt-TiO2. The higher electrochemical surface area (1.7 times), high forward/backward current ratio, and the higher CO tolerance ability for Pt-TiO2-PTP make it a superior catalyst for methanol oxidation reaction in the electrochemical process than Pt-PTP. Moreover, the catalytic activity of Pt-TiO2-PTP is further enhanced significantly with light irradiation. The cooperative effects of photo- and electrocatalysis on methanol oxidation reaction in Pt-TiO2-PTP enhance the methanol oxidation catalytic activity approximately 1.3 times higher in light illumination than in dark. Therefore, the present work will be proficient to get a light-assisted sustainable approach for developing the methanol oxidation reaction activity of Pt NP-containing catalysts in direct methanol fuel cells.