Effects of heat treatment on the structure and photocatalytic activity of polymer carbon nitride

Efficient Solar Light Driven Degradation of Tetracycline by Fe-EDTA Modified g-C3N4 Nanosheets

“…In Fe 2p XPS spectrum (Figure b), the peaks at binding energy of 710.8 and 725.8 eV belong to 2p 3/2 and 2p 1/2 of Fe­(III), respectively, ,, whereas the metallic states of Fe 2p 3/2 and 2p 1/2 show XPS signals at 706.7 and 719.8 eV that are missing from Fe-EDTA/g-C 3 N 4 . This suggests the Fe 3+ state and confirms the absence of metallic iron aggregation in Fe-EDTA/g-C 3 N 4 , which is similar to the previous report, ,, in which the Fe atoms are stabilized in the electron-rich structure of g-C 3 N 4 via Fe–N bonds. ,, As shown in Figure S3a, the binding energies (C 1s) of the samples shift to higher region with increasing amounts of Fe-EDTA, due to the changes of electron structure and physical environment. , The peak intensity at ∼284 eV is also decreased with increased amount of Fe-EDTA, which indicates that some carbon atoms may be broken during calcination and replaced by Fe dopant to form a Fe–N bond . N 1s peaks also shift to higher binding energy, which is ascribed to the interaction of Fe 3+ with the vicinal N atom, causing a decrease in the electron density of CN or C–N bonds. ,− As shown in Figure S3c, the peak intensities of Fe 2p increase with increasing amounts of Fe-EDTA.…”

“…Thus, doping Fe species into the work frame of g-C 3 N 4 can effectively inhibit the recombination of photoinduced charge carriers, which is helpful for photocatalysis reaction. As shown in Figure , when the Fe-EDTA is introduced into the g-C 3 N 4 , red-shift of the PL peaks is observed which is caused by narrowed energy band gap. ,− The weak peak and red-shift of absorption edge is related to the π*-electron delocalization in carbon nitride network due to the distortion of microstructure by Fe-EDTA modification . The PL shift is in accord with the shift of the optical absorption edge.…”

“…23,25,55 As shown in Figure S3a, the binding energies (C 1s) of the samples shift to higher region with increasing amounts of Fe-EDTA, due to the changes of electron structure and physical environment. 29,56 The peak intensity at ∼284 eV is also decreased with increased amount of Fe-EDTA, which indicates that some carbon atoms may be broken during calcination and replaced by Fe dopant to form a Fe−N bond. 31 N 1s peaks also shift to higher binding energy, which is ascribed to the interaction of Fe 3+ with the vicinal N atom, causing a decrease in the electron density of CN or C−N bonds.…”

Influence of High Temperature Synthesis on the Structure of Graphitic Carbon Nitride and Its Hydrogen Generation Ability

“…The effect of SSA on the efficiency of hydrogen production is related to the number of defects acting as charge separation sites, the higher their number, the higher the activity. However, too high a number of such defects can lead to faster recombination of charges, which could explain the lower activity of carbon nitride obtained from thiourea [68,69]. The XRD results (especially: interplanar distance), XPS (N/C ratio) and elemental analysis (hydrogen content) consistently indicate that with increasing synthesis temperature and with longer annealing time, the degree of condensation and ordering the structure of carbon nitride increases.…”

“…The effect of SSA on the efficiency of hydrogen production is related to the number of defects acting as charge separation sites, the higher their number, the higher the activity. However, too high a number of such defects can lead to faster recombination of charges, which could explain the lower activity of carbon nitride obtained from thiourea [68,69].…”