Beatriz Lara Diego dos Reis Fusari

Bio: Beatriz Lara Diego dos Reis Fusari is an academic researcher from University of São Paulo. The author has contributed to research in topics: Catalysis & Dopant. The author has co-authored 1 publications.

Effect of HCl and HNO3 on the synthesis of pure and silver-based WO3 for improved photocatalytic activity under sunlight

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 Langmuir-Hinshelwood (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•− species play a major role in acetaminophen degradation with the material containing WO3, Ag and AgCl.

Semiconductors Application Forms and Doping Benefits to Wastewater Treatment: A Comparison of TiO2, WO3, and g-C3N4

Abstract: Photocatalysis has been vastly applied for the removal of contaminants of emerging concern (CECs) and other micropollutants, with the aim of future water reclamation. As a process based upon photon irradiation, materials that may be activated through natural light sources are highly pursued, to facilitate their application and reduce costs. TiO2 is a reference material, and it has been greatly optimized. However, in its typical configuration, it is known to be mainly active under ultraviolet radiation. Thus, multiple alternative visible light driven (VLD) materials have been intensively studied recently. WO3 and g-C3N4 are currently attractive VLD catalysts, with WO3 possessing similarities with TiO2 as a metal oxide, allowing correlations between the knowledge regarding the reference catalyst, and g-C3N4 having an interesting and distinct non-metallic polymeric structure with the benefit of easy production. In this review, recent developments towards CECs degradation in TiO2 based photocatalysis are discussed, as reference catalyst, alongside the selected alternative materials, WO3 and g-C3N4. The aim here is to evaluate the different techniques more commonly explored to enhance catalyst photo-activity, specifically doping with multiple elements and the formation of composite materials. Moreover, the possible combination of photocatalysis and ozonation is also explored, as a promising route to potentialize their individual efficiencies and overcome typical drawbacks.

Research Progress of Tungsten Oxide-Based Catalysts in Photocatalytic Reactions

Abstract: Photocatalysis technology is a potential solution to solve the problem of environmental pollution and energy shortage, but its wide application is limited by the low efficiency of solar energy conversion. As a non-toxic and inexpensive n-type semiconductor, WO3 can absorb approximately 12% of sunlight which is considered one of the most attractive photocatalytic candidates. However, the narrow light absorption range and the high recombination rate of photogenerated electrons and holes restrict the further development of WO3-based catalysts. Herein, the studies on preparation and modification methods such as doping element, regulating defects and constructing heterojunctions to enlarge the range of excitation light to the visible region and slow down the recombination of carriers on WO3-based catalysts so as to improve their photocatalytic performance are reviewed. The mechanism and application of WO3-based catalysts in the dissociation of water, the degradation of organic pollutants, as well as the hydrogen reduction of N2 and CO2 are emphatically investigated and discussed. It is clear that WO3-based catalysts will play a positive role in the field of future photocatalysis. This paper could also provide guidance for the rational design of other metallic oxide (MOx) catalysts for the increasing conversion efficiency of solar energy.