Estratégias e materiais utilizados em fotocatálise heterogênea para a geração de hidrogênio através da fotólise da água

Marques, Fabielle Castelan; Stumbo, Alexandre M.; Canela, Maria Cristina

doi:10.21577/0100-4042.20170015

Cited by 3 publications

(3 citation statements)

References 32 publications

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“…It is also worth emphasizing the Z-scheme type heterojunctions within type II heterostructures, which are inspired by the natural photosynthesis of plants, where CO 2 and water react to form carbohydrates and O 2 [25,26]. This type of system shows significant advantages over conventional type II heterojunctions, including greater efficiency in photogenerated charge separation and higher redox potential at different active sites [27].…”

Section: Understanding the Influence Of Doping And Heterojunctions On...mentioning

confidence: 99%

Zinc tungstate: a review on its application as heterogeneous photocatalyst

2022

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ZnWO 4 crystallizes in a monoclinic wolframite-like structure, which has been studied for applications in heterogeneous photocatalysis for degradation, oxidation, and reduction of various contaminants. This type of tungstate has proved to be an efficient photocatalyst under both ultraviolet and visible light irradiation and, when ZnWO 4 forms a heterostructure with other semiconductors or when it is doped with different ions, it has a great efficiency under sunlight irradiation. For instance, the optimization of ZnWO 4 efficiency has been attained by its heterojunction with different semiconductors such as ZnO, one of the most used materials for this purpose, but also with other compounds such as BiOBr, FeWO 4 , TiO 2 , WO 3 , Bi 2 WO 6 , among others. In addition, doping ZnWO 4 with the Ti 4+ , Bi 3+ , Ce 3+ , and Co 2+ metal ions or with nonmetals (Fand N 3-) can also increase the photocatalytic yield of the material. The photocatalytic properties of ZnWO 4 -based catalysts have been explored toward inorganic and organic molecules. However, among the variety of target molecules, organic pollutants such as methylene blue, methyl orange, and rhodamine B dyes appear as the most investigated in studies involving photocatalysis in the presence of ZnWO 4 . In our review, we summarize important literature works, highlighting the advancement in photocatalysis using ZnWO 4 .

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Section: Understanding the Influence Of Doping And Heterojunctions On...mentioning

confidence: 99%

Zinc tungstate: a review on its application as heterogeneous photocatalyst

2022

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“…According to Marques et al (2017), sacrificial agents are electron donor compounds that react irreversibly with the holes (h þ ) of the catalysts, resulting in greater quantum efficiency, that is, it prevents the deactivation of the catalyst that happens due to high electron/hole recombination speed (Marques et al 2017). Momeni et al (2020) explains that sacrificing agents can be used to minimize the recombination of electron-gap pairs in aqueous medium and, among the most used additives, methanol, ethanol, sugars, organic acids and glycerols, which have been used to increase the reaction rate (Momeni et al 2020).…”

Section: Influence Of the Matrix Radiation Source And Presence Of Additivementioning

confidence: 99%

Functioned catalysts with magnetic core applied in ibuprofen degradation

Lenzi

Lopes

Andrade

et al. 2021

Water Science and Technology

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In the present work, the performance of Ag/ZnO/CoFe2O4 magnetic photocatalysts in the photocatalytic degradation of Ibuprofen (IBP) was evaluated. This study considered the use of pure Ag/ZnO (5% Ag) and also use the Ag/ZnO/CoFe2O4 magnetic catalysts containing different amounts (5, 10 and 15% wt) of cobalt ferrite (CoFe2O4). The catalysts were characterized by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and photoacoustic Spectroscopy. To carried the photocatalytic degradation reaction, different concentrations of the ibuprofen contaminant solution (10, 20 and 30 ppm) and different concentrations of photocatalyst were tested (0.3 gL−1, 0.5 gL−1 and 1.0 gL−1). The reaction parameters studied were: IBP concentration, catalyst concentration, adsorption and photolysis, influence of the matrix, radiation source (solar and artificial) and the effect of organic additive. At the end of the photocatalytic tests, the best operation conditions were defined. Considering the obtained results of degradation efficiency and magnetic separation, the optimal parameters selected to proceed with the other tests of the study were: ibuprofen solution concentration 10 ppm, Ag/ZnO/CoFe2O4(5%) catalyst at a concentration of 0.3 g L−1 and pH 4.5 of the reaction medium. The results indicated the feasibility of magnetic separation of the synthesized catalysts. A long duration test indicated that the catalyst exhibits stability throughout the degradation reaction, as more than 80% of ibuprofen was degraded after 300 minutes. The photocatalytic activity was directly affected by the ferrite load. The higher the nominal load of ferrite, the lower the performance in ibuprofen degrading. It was also observed that the smallest amount of ferrite studied was enough for the catalyst to be recovered and reused. The adsorption and photolysis tests did not show significant results in the IBP degradation. In addition, it was possible to verify that the aqueous matrix, the use of solar radiation and the addition of additive (acid formic) interfered direct in the process. The catalyst reuse tests indicated that it can be recovered and reused at least three times without considerable catalytic activity loss.

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“…Sob irradiação com fótons de energia superior à energia de bandgap (E g , energia que separa a banda de valência (BV) da banda de condução (BC) do semicondutor/fotocatalisador), elétrons na BV são excitados para a BC, gerando o par elétron-lacuna que participa de reações redox. [4][5][6][7] Para realizar a fotodecomposição da molécula de água, é necessário que o limiar da banda de condução do semicondutor esteja posicionado em potenciais mais negativos que o potencial de redução da H 2 O a H 2 (E r o = -0,83 V vs EPH em pH básico, ou E r o (H + /H 2 ) = 0 V em pH = 0), enquanto que o limiar da banda de valência deve estar posicionado em potenciais mais positivos que aquele de oxidação de H 2 O a O 2 (E r o = +1,23 V vs EPH, pH = 0 ou E r o (OH -/O 2 ) = +0,40 V em pH básico). Termodinamicamente, a decomposição da água é uma reação não espontânea (ΔG o = +238 kJ mol -1 ; ΔE o = -1,23 V), sendo necessário o suprimento de energia que coincide com fótons de energia de l ≤ 1000 nm (i.e., 1,23 eV ≈ energia de fótons de 1000 nm).…”

Section: Introductionunclassified

AVALIAÇÃO DO PAPEL DO ÓXIDO DE GRAFENO (GO) NA GERAÇÃO FOTOCATALÍTICA DE HIDROGÊNIO EM SISTEMAS BINÁRIOS (GO-CdS) E TERNÁRIOS (Pt-GO-CdS)

Almeida¹,

Trindade²,

Silva³

et al. 2018

Quim. Nova

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EVALUATION OF THE GRAPHENE OXIDE (GO) ROLE IN THE PHOTOCATALYTIC GENERATION OF HYDROGEN IN BINARY (GO-CdS) AND TERNARY (Pt-GO-CdS) SYSTEMS. Water splitting is a promising process to produce hydrogen from friendly feedstock and solar energy. In this work we have evaluated binary (GO-CdS) and ternary (Pt-GO-CdS) hybrid photocatalysts for hydrogen production assisted by visible light irradiation. Cadmium sulfide and composites with GO were prepared by sonochemical and thermal methods. GO addition took place by different strategies: during the synthesis or by mechanical mixture. A variety of configurations was tested and the best performance in hydrogen production among all materials was the ternary photocatalyst named Pt(GO/CdS TT), whose hydrogen production rate was 651 µmol g cat-1 h-1. Such material was obtained by thermal method with GO addition during the synthesis. Additionally, the XRD and Raman analyses have confirmed the GO photoreduction during photocatalytic hydrogen evolution.

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Estratégias e materiais utilizados em fotocatálise heterogênea para a geração de hidrogênio através da fotólise da água

Cited by 3 publications

References 32 publications

Zinc tungstate: a review on its application as heterogeneous photocatalyst

Zinc tungstate: a review on its application as heterogeneous photocatalyst

Functioned catalysts with magnetic core applied in ibuprofen degradation

AVALIAÇÃO DO PAPEL DO ÓXIDO DE GRAFENO (GO) NA GERAÇÃO FOTOCATALÍTICA DE HIDROGÊNIO EM SISTEMAS BINÁRIOS (GO-CdS) E TERNÁRIOS (Pt-GO-CdS)

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