Hydrogen-Treated TiO<sub>2</sub> Nanorods Decorated with Bimetallic Pd–Co Nanoparticles for Photocatalytic Degradation of Organic Pollutants and Bacterial Inactivation
In Seon Hwang, Velu Manikandan, Ruturaj P. Patil, Mahadeo A. Mahadik, Weon‐Sik Chae, Hee‐Suk Chung, Sun Hee Choi, Jum Suk Jang
Abstract
Herein, first, we synthesize a multifunctional photocatalyst via metal oxides loaded (Co/Pd) on acid-treated TiO 2 nanorods (ATO) and further introduce hydrogen annealing treatment. The hydrogen annealing treatment introduces metal oxides converted into a bimetallic form and delays the photogenerated charge recombination process. Also, oxygen vacancies are formed due to the partial reduction of Ti 4+ to Ti 3+ sites. In addition, oxygen vacancies help to improve photocatalytic degradation and antibacterial activity. The hydrogen-treated photocatalyst (Pd(1)Co(1)/ATO (red)) demonstrates high degradation efficiencies of 99.63 and 99.90% (180 min) for orange II dye and BPA degradation, respectively, and an antibacterial activity of 97.00% (120 min) under one sun irradiation. In the photocatalytic removal of abiotic pollutants and live bacteria, the trapping experiment suggests that radical species ( • O 2 – and • OH), assisted by photoinduced holes, are responsible for the high activities. The photoelectrochemical performance and time-resolved PL (TRPL) study illustrate that Pd(1)Co(1)/ATO (red) reveals superior photoelectrochemical charge separation (electron–hole), lower resistance, and shorter lifetime (τ 1 = 0.40 ns) as a photocatalyst. Finally, plausible charge transport mechanisms are proposed for the photocatalytic degradation of organic dye and bacterial disinfection over the Pd(1)Co(1)/ATO (red) photocatalyst.