Structural and Physicochemical Properties of Carbon Nitride Nanoparticles via Precursor Thermal Treatment: Effect on Methyl Orange Photocatalytic Discoloration
Por:
Gomez-Velazquez, Laura S., Madriz, Lorean, Rigoletto, Monica, Laurenti, Enzo, Bizarro, Monserrat, Dell'Arciprete, Maria L., Gonzalez, Monica C.
Publicada:
26 may 2023
Ahead of Print:
1 may 2023
Categoría:
Materials science (miscellaneous)
Resumen:
In this work, we synthesized and characterized carbonnitride
(CN)nanoparticles obtained by the thermal treatment (550 degrees C) of
urea,melamine, dicyandiamine, and dicyandiamine-barbituric acid in an
openreactor and evaluated the effect of different precursors on the
photocatalyticperformance. CNs obtained from melamine, dicyandiamine,
and dicyandiamine-barbituricacid were 3D melon-type structures. On the
other hand, CN obtainedfrom urea was a 2D microporous, amorphous
structure whose melon orgraphitic arrangement could not be determined.
The presence of structuraldefective states (mainly C radicals) was
corroborated by EPR studiesof the solids. The photocatalytic activity of
CN powders for methylorange (MO) discoloration was investigated using
350 nm and simulatedsolar light (SSL) irradiation. MO removal
efficiencies were correlatedwith the particle's energy gap, specific
surface area, degreeof crystallinity, and C radical defects produced
upon irradiation.Moreover, the obtained conduction and valence band
potentials in therange of -0.60 and + 2.14 V vs NHE (pH = 7),
respectively,evidence CN capacity to oxidize water to hydroxyl radicals
(HO center dot) and reduce O-2 to superoxide radical anions(O-2 (center
dot-)). The formation of bothradicals upon SSL irradiation of CN
suspensions was confirmed by EPRexperiments. The largest specific
surface area, the highest chargecarrier density, and the amount of C
radical defects observed forCN obtained from urea (CNu) account for
their highest photocatalyticperformance. However, the estimated CNu
photonic efficiency of ca.8% still indicates a deficient
separation/migration efficiency ofphotoinduced charge carriers. Despite
CNu performance being higherthan those of other CNs obtained from the
thermal treatment of simpleprecursors, further environmentally friendly
strategies are stillneeded to overcome the intrinsic disadvantages of CN
before it maybe employed in technological applications. A discussion on
probableCN mechanisms forming reactive species and leading to MO
decolorizationis given.
Filiaciones:
Gomez-Velazquez, Laura S.:
Univ Nacl La Plata, Inst Invest Fisicoquim Teor & Aplicadas INIFTA, CCT La Plata CONICET, RA-1900 La Plata, Argentina
Madriz, Lorean:
Univ Nacl La Plata, Inst Invest Fisicoquim Teor & Aplicadas INIFTA, CCT La Plata CONICET, RA-1900 La Plata, Argentina
CCT La Plata CONICET, Inst Tecnol Chascomus INTECH, RA-B7130 Chascomus, Buenos Aires, Argentina
Univ Nacl San Martin UNSAM, Escuela Bio & Nanotecnol, RA-7130 Chascomus, Buenos Aires, Argentina
Rigoletto, Monica:
Univ Torino, Dipartimento Chim, I-10125 Turin, Italy
Laurenti, Enzo:
Univ Torino, Dipartimento Chim, I-10125 Turin, Italy
Bizarro, Monserrat:
Univ Nacl Autonoma Mexico, Inst Invest & Mat, Circuito Exterior S-N,Ciudad Univ, Coyoacan, Mexico
Dell'Arciprete, Maria L.:
Univ Nacl La Plata, Inst Invest Fisicoquim Teor & Aplicadas INIFTA, CCT La Plata CONICET, RA-1900 La Plata, Argentina
Gonzalez, Monica C.:
Univ Nacl La Plata, Inst Invest Fisicoquim Teor & Aplicadas INIFTA, CCT La Plata CONICET, RA-1900 La Plata, Argentina
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