Correlation between Photocatalytic Properties of ZnO and Generation of Hydrogen Peroxide—Impact of Composite ZnO/TiO[sub.2] Rutile and Anatase

• Published in: Catalysts 2022-11, Vol.12 (11)
• Main Authors: Mediouni, Nouha, Dappozze, Frederic, Khrouz, Lhoussain, Parola, Stephane, Amara, Abdesslem Ben Haj, Rhaiem, Hafsia Ben, Jaffrezic-Renault, Nicole, Namour, Philippe, Guillard, Chantal
• Format: Article
• Language: English
• Subjects: Hydrogen peroxide; Zinc oxide
• ISSN: 2073-4344; 2073-4344
• DOI: 10.3390/catal12111445

The generation of hydrogen peroxide on commercial and synthesized ZnO from different precursors was studied using two model molecules, formic acid (FA) and phenol (Ph), as well as phenolic intermediates, hydroquinone (HQ), benzoquinone (BQ), and catechol (CAT). The samples were characterized using X-ray Diffraction (XRD), Transmission Electronic Microscopy (TEM), RAMAN, and Electron Paramagnetic Resonance (EPR) before evaluating their photocatalytic properties. We found that the improved efficiency is accompanied by a high level of H[sub.2]O[sub.2] production, fewer oxygen vacancies, and that the number of moles of H[sub.2]O[sub.2] formed per number of carbon atoms removed is similar to the degradation of FA and Ph with a factor of 1. Moreover, a comparative study on the formation of H[sub.2]O[sub.2] was carried out in the presence of TiO[sub.2] rutile and TiO[sub.2] anatase, with commercial ZnO. Our results exhibit the impact of the presence of TiO[sub.2] on the decomposition of hydrogen peroxide and the formation of phenolic intermediates, which are much lower than those of ZnO only, which is in agreement with the formation of hydroxyl radicals °OH and superoxide O[sub.2]°[sup.−] degrading significantly hydroquinone (HQ), benzoquinone (BQ), and cathecol (CAT).