pH-dependent surface properties of N–Cdots obtained by the hydrothermal method with multicolored emissions

Silva, Atailson Oliveira da; Rodrigues, Marcelo Oliveira; Sousa, Marcelo Henrique; Campos, Alex Fabiano Cortez

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Campo DC	Valor	Idioma
dc.contributor.author	Silva, Atailson Oliveira da	-
dc.contributor.author	Rodrigues, Marcelo Oliveira	-
dc.contributor.author	Sousa, Marcelo Henrique	-
dc.contributor.author	Campos, Alex Fabiano Cortez	-
dc.date.accessioned	2021-05-31T12:33:49Z	-
dc.date.available	2021-05-31T12:33:49Z	-
dc.date.issued	2021	-
dc.identifier.citation	SILVA, Atailson Oliveira da et al. pH-dependent surface properties of N–Cdots obtained by the hydrothermal method with multicolored emissions. Colloids and Surfaces A: physicochemical and engineering aspects, v. 621, 126578, 2021. DOI: https://doi.org/10.1016/j.colsurfa.2021.126578.	pt_BR
dc.identifier.uri	https://repositorio.unb.br/handle/10482/41061	-
dc.language.iso	Português	pt_BR
dc.publisher	Elsevier B.V.	pt_BR
dc.rights	Acesso Restrito	pt_BR
dc.title	pH-dependent surface properties of N–Cdots obtained by the hydrothermal method with multicolored emissions	pt_BR
dc.type	Artigo	pt_BR
dc.subject.keyword	Pontos de carbono dopados com N	pt_BR
dc.subject.keyword	Potencial zeta	pt_BR
dc.subject.keyword	Fotoluminescência	pt_BR
dc.identifier.doi	https://doi.org/10.1016/j.colsurfa.2021.126578	pt_BR
dc.relation.publisherversion	https://www.sciencedirect.com/science/article/abs/pii/S0927775721004477?via%3Dihub	pt_BR
dc.description.abstract1	This study addresses the pH-dependent surface properties of hydrophilic nitrogen-doped carbon dots (N–Cdots) elaborated through a hydrothermal method. The samples were obtained using p-phenylenediamine and urea (N–CdotR), and citric acid and ammonium hydroxide (N–CdotB) as precursors, respectively. The structural and morphological properties of the N-Cdots were investigated using TEM, Raman spectroscopy and FTIR. The nanoparticles of both samples exhibited a large number of hydrophilic surface groups. Potentiometric and conductometric titrations were used to determine the pKs of the N–Cdots surface groups (pK1 = 3.4 and pK2 = 6.6 for N–CdotR; pK1 = 7.6 and pK2 = 9.9 for N–CdotB). Measurements of zeta potential and hydrodynamic diameter as a function of pH indicated that the charge modulation and colloidal stability of the N–Cdots are controlled mainly by amine and carboxyl groups in N–CdotR and carboxyl and phenolic groups in N–CdotB. The optical properties of the N–Cdots were characterized using UV-Vis spectroscopy. The photoluminescence results indicated that the acid-base behavior of the surface groups promotes changes in the energy emission states, with blue- and redshifts. Moreover, the N–Cdots presented significant quantum fluorescent yield (QY = 25% for N–CdotR and QY = 30% for N–CdotB) and good photostability. The whole of these results demonstrates that pH is a key parameter to monitor the colloidal stability and optical properties of N–Cdots as well as their potential technological applications.	pt_BR
dc.description.unidade	Faculdade UnB Ceilândia (FCE)	pt_BR
dc.description.unidade	Instituto de Química (IQ)	pt_BR
dc.description.unidade	Faculdade UnB Planaltina (FUP)	pt_BR
dc.description.ppg	Programa de Pós-Graduação em Ciências e Tecnologias em Saúde	pt_BR
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