Dulce Melo

Prof. Dr. Dulce Melo


Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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8 February 2024 in Nanomaterials
Verified
Journal Article
Open access
PDF file
FMFernando Velcic Maziviero
Fernando Velcic Maziviero
DMDulce Melo
Dulce Melo
RMRodolfo Luiz Bezerra de Araújo Medeiros
Rodolfo Luiz Bezerra de Araújo Medeiros
ÂOÂngelo A. S. Oliveira
Ângelo A. S. Oliveira
HMHeloísa P. Macedo
Heloísa P. Macedo
EJEdisson Morgado Jr.
Edisson Morgado Jr.
Hybrid perovskites, materials composed of metals and organic substances in their structure, have emerged as potential materials for the new generation of photovoltaic cells due to a unique combination of optical, excitonic and electrical properties. Inspired by sensitization techniques on TiO2 substrates (DSSC), CH3NH3PbBr3 and CH3NH3PbI3 perovskites were studied as a light-absorbing layer as well as an electron–hole pair generator. Photovoltaic cells based on per-ovskites have electron and hole transport layers (ETL and HTL, respectively), separated by an ac-tive layer composed of perovskite itself. Major advances subsequently came in the preparation methods of these devices and the development of different architectures, which resulted in an efficiency exceeding 23% in less than 10 years. Problems with stability are the main barrier to the large-scale production of hybrid perovskites. Partially or fully inorganic perovskites appear promising to circumvent the instability problem, among which the black perovskite phase CsPbI3 (α-CsPbI3) can be highlighted. In more advanced studies, a partial or total substitution of Pb by Ge, Sn, Sb, Bi, Cu or Ti is proposed to mitigate potential toxicity problems and maintain device efficiency.

22 June 2024 in Waste Management
Verified
Journal Article
Closed access
VLVitor Fernandes Dias Lopes
Vitor Fernandes Dias Lopes
José Luiz Francisco AlvesJosé Luiz Francisco Alves
José Luiz Francisco Alves
ESEdyjancleide Rodrigues da Silva
Edyjancleide Rodrigues da Silva
JMJúlio de Andrade Oliveira Marques
Júlio de Andrade Oliveira Marques
DMDulce Melo
Dulce Melo
RBRenata Martins Braga
Renata Martins Braga

18 January 2023 in Nanomaterials
Verified
Journal Article
Open access
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JBJoana M. F. Barros
Joana M. F. Barros
GFGlauber J. T. Fernandes
Glauber J. T. Fernandes
MAMarcio D. S. Araujo
Marcio D. S. Araujo
DMDulce Melo
Dulce Melo
AGAmanda Gondim
Amanda Gondim
Antonio S. AraujoAntonio S. Araujo
Antonio S. Araujo
The nanostructured lanthanide-silica materials of the Ln–SiO2 type (Ln = La, Ce, Pr, Nd, Eu, Gd, Dy, Yb, Lu) were synthesized by the hydrothermal method at 100 °C, using cetyltrimethylammonium as a structural template, silica gel and sodium silicate as a source of silicon, and lanthanide oxides, with Si/Ln molar ratio = 50. The resulting materials were calcined at 500 °C using nitrogen and air, and characterized by X-ray diffraction (XRD), Fourier-Transform infrared absorption spectroscopy, scanning electron microscopy, thermogravimetry (TG), surface area by the BET method and acidity measurements by n-butylamine adsorption. The XRD and chemical analysis indicated that the SiO2 presented a hexagonal structure and the incorporation of lanthanides in the structure changes the properties of the Ln–SiO2 materials. The heavier the lanthanide element, the higher the Si/Ln ratio. The TG curves showed that the decomposition of the structural template occurs in the materials at temperatures below 500 °C. The samples showed variations in specific surface area, mean pore diameter and silica wall thickness, depending on the nature of the lanthanide. The incorporation of different lanthanides in the silica generated acid sites of varied strength. The hydrothermal stability of the Ln–SiO2 materials evaluated at high temperatures, evidenced that the properties can be controlled for application in adsorption and catalysis processes.

29 March 2024 in Forests
Verified
Journal Article
Open access
PDF file
MAMarcela Cristina Pereira dos Santos Almeida
Marcela Cristina Pereira dos Santos Almeida
JSJanduir Egito da Silva
Janduir Egito da Silva
WBWillame Batista
Willame Batista
José Luiz Francisco AlvesJosé Luiz Francisco Alves
José Luiz Francisco Alves
DMDulce Melo
Dulce Melo
RBRenata Martins Braga
Renata Martins Braga
In the past few years, wind power has become a viable alternative in Brazil to diversify the energy mix and mitigate pollutant emissions from fossil fuels. Significant wind energy generation potential is inherent in the Brazilian Northeast state of Rio Grande do Norte, due to prevailing strong winds along the coastline and elevated regions. However, clean and renewable wind energy may lead to potential biodiversity impacts, including the removal of native vegetation during plant construction and operation. This case study explores the flash pyrolysis-based valorization of three commonly suppressed species, namely Cenostigma pyramidale (CP), Commiphora leptophloeos (CL), and Aspidosperma pyrifolium (AP), in a wind farm situated within the Mato Grande region of Rio Grande do Norte State. The study centers on determining their bioenergy-related properties and assessing their potential for producing phenolic-rich bio-oil. The investigation of three wood residues as potential sources of high-value chemicals, specifically phenolic compounds, was conducted using a micro-furnace type temperature programmable pyrolyzer combined with gas chromatography/mass spectrometry (Py–GC/MS setup). The range of higher heating values observed for three wood residues was 17.5–18.4 MJ kg−1, with the highest value attributed to AP wood residue. The bulk density ranged from 126.5 to 268.7 kg m−3, while ash content, volatile matter content, fixed carbon content, and lignin content were within the respective ranges of 0.8–2.9 wt.%, 78.5–89.6 wt.%, 2.6–9.5 wt.%, and 19.1–30.6 wt.%. Although the energy-related properties signifying the potential value of three wood residues as energy resources are evident, their applicability in the bioenergy sector can be expanded via pelleting or briquetting. Yields of phenolic compounds exceeding 40% from the volatile pyrolysis products of CL and AP wood residues at 500 °C make them favorable for phenolic-rich bio-oil production. The findings of this study endorse the utilization of wood residues resulting from vegetation suppression during the installation of wind energy plants as potential feedstocks for producing bioenergy and sustainable phenolic compounds. This presents a solution for addressing a regional environmental concern following the principles of green chemistry.