Anatase TiO2-Decorated Graphitic Carbon Nitride for Photocatalytic Conversion of Carbon Dioxide

Abstract

Three types of graphitic carbon nitride (gCN) nanosheets were derived from direct thermal condensation of urea, melamine, and dicyandiamide, respectively. As the sample (uCN) synthesized from urea exhibited porous morphology and highest surface area among other gCN, anatase TiO2 nanoparticles were then in-situ deposited on uCN via solvothermal process without further calcination. The resultant Ti/uCN_x samples remained with higher surface area and exhibited visible-light activity. The derived band structure of each sample also confirmed its ability to photoreduce CO2. XPS results revealed surface compositions of each sample. Those functional groups governed adsorption of reactant, interfacial interaction, electron transfer rate, and consequently influenced the yield of products. Carbon monoxide and methanol were detected from LED-lamp illuminated samples under appropriate moisture content. Samples with higher ratio of terminal amine groups produced more CO. The presence of hydroxyl groups promoted the initial conversion of methanol. The obtained Ti/uCN_0.5 and Ti/uCN_1.5 samples exhibited better quantum efficiency toward CO2 conversion and demonstrated stability to consistently produce CO under cycling photoreaction.

ZnO-Modified g-C3N4: A Potential Photocatalyst for Environmental Application

“…The zeta potential value of GCN–Zn0.4 was found to be 5.91, 3.42, −8.69, −11, −21.7, and −17 mV for solution pH of 4, 5, 7.6, 9, 10, and 11. The increased negative surface charge of the photocatalyst in alkaline medium would enhance the adsorption of positively charged MB dye molecules, which would further facilitate its photodegradation. , At an optimum pH condition, degradation of MB reached 97% in 80 min, and the apparent rate constant value increased 1.8 times in comparison to normal pH condition. The apparent rate constant value and the degradation efficiency for GCN–ZnO0.4 measured for all photocatalytic reactions for 80 min at the pH range 4–11 are represented in Table .…”

Synergistically enhanced solar light‐driven degradation of hazardous food colorants by ultrasonically derived MgFe2O4/S‐doped g‐C3N4 nanocomposite: A Z‐scheme system‐based heterojunction approach

“…The typical peaks located at 399.2, 400.7, and 404.8 eV could be assigned to tertiary nitrogen N‐(C) 3 groups, H‐bonded amino groups (N‐H structural), and for π‐excitation, respectively. [ 105 ] The appearance of the peak in the binding energy range of 160–175 eV confirmed the inclusion of sulfur atom in the carbon nitride matrix. As represented in Figure 6c, the peak positioned at 169.6 eV corresponds to the existence of C‐S bond.…”

Fabrication of g-C3N4/ZnO Nanoheterostructures for Effective Degradation of Methylene Blue Dye under Visible Light Irradiation

“…Contrary, in alkaline medium above the pH (6.7) catalyst surface acquires negative charge due to the adsorption of OH -, which attract electrostatically to the cationic dye molecules that lead to increase the adsorption of MO dye. Due to this the degradation of MB dye would be further enhanced [46]. Moreover, in alkaline pH OHions can produce hydroxyl (•OH) radicals that also triggers the degradation rate of dye.…”