Effect of HCl and HNO3 on the synthesis of pure and silver-based WO(3 )for improved photocatalytic activity under sunlight

Author(s)

Palharim, Priscila Hasse ^[1] ; Fusari, Beatriz Lara Diego dos Reis ^[1] ; Ramos, Bruno ^{[1, 2]} ; Otubo, Larissa ^[3] ; Teixeira, Antonio Carlos Silva Costa ^[1]

Affiliation

^[1] Univ Sao Paulo, Escola Politecn, Dept Chem Engn, Res Grp Adv Oxidat Processes AdOx, Av Prof Luciano Gualberto Tr 3, 380, Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Dept Met & Mat Engn, Lab Ceram Proc, Escola Politecn, Av Prof Mello Moraes, 2463, Sao Paulo, SP - Brazil

^[3] Inst Pesquisas Energet & Nucl IPEN CNEN, Cidade Univ, Av Prof Lineu Prestes, 2242, Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY; v. 422, JAN 1 2022.
• Web of Science Citations: 0

Abstract

Heterogeneous photocatalysis have been considered an important and efficient alternative water and wastewater treatment process. In this area, different semiconductors, such as tungsten trioxide, have been investigated aiming to enhance photocatalytic performance. WO3 is known to be an efficient material with high stability in acidic conditions. In the present work, pure and Ag/AgCl-doped WO3 photocatalysts were synthesized by a simple hydrothermal method. A discussion of the effects of two pH-controlling agents, HCl and HNO3, in the final properties of the catalyst is reported for the first time. The materials were characterized by XRD, BET, SEM, EDS and UV-vis DRS. All catalysts showed similar or enhanced band gap values compared to a standard photocatalyst benchmark (TiO2 P25). The type of acid did not lead to significant differences in morphology or photocatalytic activity of undoped catalysts. In contrast, doped catalysts prepared using HCl resulted in particles of flower-like morphology, with higher uniformity and slightly narrower band gap values. Furthermore, the use of HCl in the synthesis of silver-doped WO3 resulted in catalysts containing AgCl, while Ag0 was the major dopant species when HNO3 was used. All materials exhibited good photocatalytic activity, with a maximum of 75.4% acetaminophen degradation under simulated sunlight achieved by the catalyst prepared with HCl and doped with 5% Ag-equivalent. For this catalyst, the degradation kinetics was found to be consistent with the LangmuirHinshelwood (L-H) model, and reusability tests showed no significant decrease in the degradation efficiency after four cycles. Finally, the effects of different scavengers suggest that O2 center dot- species play a major role in acetaminophen degradation with the material containing WO3, Ag and AgCl. (AU)

• FAPESP's process: 18/21271-6 - SOLAR DEGRADATION OF POLLUTANTS OF EMERGING CONCERN: PHOTOREACTORS AND INNOVATIVE TREATMENTS
• Grantee: Antonio Carlos Silva Costa Teixeira
• Support Opportunities: Regular Research Grants