Fabrication, characterization, and photocatalytic performance of exfoliated g-C3N4–TiO2 hybrids

Abstract

a b s t r a c tA series of TiO 2 hybrids composited with exfoliated g-C 3 N 4 nanosheets (CNs) were successfully synthesized through a facile sol-gel method and fully characterized by X-ray diffraction patterns (XRD), Fourier transform-infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and UV-vis diffuse reflectance spectra (UV-vis DRS). The CNs-TiO 2 hybrids were exposed to visible light irradiation and showed much higher catalytic capability toward degrading dye rhodamine B (RhB) comparing with bare TiO 2 and N-TiO 2 . The sample CNs-TiO 2 -0.05 exhibited the largest apparent reaction rate constant among all CNs-TiO 2 hybrids, which was 2.4 times and 7.0 times as high as bare TiO 2 and N-TiO 2 , respectively. The enhanced catalytic efficiency could be mainly attributed to the well-matched band gap structure with heterojunction interface, suitable specific surface area, and favorable optical property. In addition, active species trapping experiments were conducted, revealing that photoinduced holes (h + ) had a severe influence on catalytic outcome, through which a possible catalytic mechanism was finally realized and proposed.

Ag/Bi12O17Cl2 composite: A case study of visible-light-driven plasmonic photocatalyst

“…To detect active radical species generated in photocatalytic process, 1.0 mM IPA and EDTA-2Na were introduced in the presence of composite AB4 during photocatalytic experiments for capturing hydroxyl radicals ( • OH) and holes (h + ), respectively [22,23]. The formation of superoxide radicals ( • O 2 − ) was checked by adding 25 M NBT in the place of RhB in solution [24].…”

Enhanced visible-light-driven photocatalytic performance of porous graphitic carbon nitride

“…Below and over that concentration, the porosity and specific surface area of samples shrank. An enlarged specific surface area is able to increase the interfacial surface between catalysts and pollutant molecules and provide abundant active sites to contact with reactant molecules and hereby enhanced the visible-light harvesting [21]. In addition, the sufficient porosity of samples facilitates both the immigration of reactants and export of degraded products, and multiple scattering of visible light.…”

“…As a result, many efforts have been devoted to modify synthetic procedures toward g-C 3 N 4 to gain an efficient photocatalytic system, such as doping with metal oxides or nonmetal elements [9][10][11][12][13], construction of porous or hierarchical nanostructures [14][15][16], and combining other semiconductors with suitable band structures [17][18][19][20][21][22]. Among strategies mentioned above, the fabrication of porous g-C 3 N 4 from the precursor of prononated melamine is quite promising and possible to achieve satisfactory catalytic efficiency.…”

Fabrication, characterization, and visible-light photocatalytic performance of ternary plasmonic composites

“…Band gap energies (E g ) of these semiconductors were estimated via an empirical equation ˛h = A(hv-Eg) n/2 and ␣, v, E g and A refers to the absorption coefficient, light frequency, band gap energy, and a constant, respectively. It is generally realized that anatase TiO 2 undergoes an indirect transition and correspondingly n is set as 4 [31]. As listed in Table 1, E g values increase with the decrease of TiO 2 /SiO 2 mass ratio in WTS series and the increase of Ag deposition in AgWTS series.…”

“…Specifically, 1.0 mM isopropanol alcohol (IPA) or disodium ethylenediaminetetraacetate (EDTA-2Na) was introduced to check the presence of hydroxyl radicals ( • OH) or produced holes (h + ) [31,32]. In addition, 25 M nitroblue tetrazolium (NBT) was added into reaction system in place of RhB to analyze superoxide radicals ( • O 2 − ) that might probably produce [33].…”