Fragmented phosphorus-doped graphitic carbon nitride nanoflakes with broad sub-bandgap absorption for highly efficient visible-light photocatalytic hydrogen evolution

Effect of calcination temperature, pH and catalyst loading on photodegradation efficiency of urea derived graphitic carbon nitride towards methylene blue dye solution

“…4(c and f). 32 Samples prepared at 600 C and 650 C resulted in contraction of layered akes of g-C 3 N 4 suggesting the possibility of reduction of the surface area at calcination temperature above 550 C.…”

“…40 As revealed from BET analysis, the increased surface area for g-C 3 N 4 prepared at 550 C as a consequence of morphological evolution caused due to appropriate calcination temperature, which not only can lead to the formation of surface active sites for reaction but can also facilitate the separation of charge carrier because exfoliated and altered structures can reduce distance of migration for photogenerated charge carriers and thus can decrease the probability of charge recombination. 32 From DRS analysis it was found that the g-C 3 N 4 prepared at 550 C also showed better ability for the absorption of light and thus may result in enhancement of photoactivity. The calculated value of reaction rate constant in case of g-C 3 N 4 at 550 C was found to be 2 to 1.5 times higher than g-C 3 N 4 prepared at other temperature.…”

“…21,[24][25][26][27][28][29][30] In addition to above mentioned strategies to modify g-C 3 N 4 , various studies showed that the calcination temperature, as well as the precursor used for synthesis greatly inuence the structure, optical properties and morphology of the as-prepared sample. 20,31,32 The above discussion gives us a tremendous opportunity to explore more of the potential of the g-C 3 N 4 as promising photocatalyst towards photodegradation of dyes.…”

One-step scalable synthesis of honeycomb-like g-C3N4 with broad sub-bandgap absorption for superior visible-light-driven photocatalytic hydrogen evolution

“…Recently, integration of nanostructure design with a subbandgap has provided an efficient route for facilitating the separation of photogenerated electron-hole pairs while simultaneously increasing the number of active sites as well as the light harvesting of g-C 3 N 4 . [29][30][31][32][33][34][35][36][37] Additionally, a synergistic effect between nanostructure design and sub-bandgap creation endowed the obtained g-C 3 N 4 with remarkably improved photocatalytic H 2 production activity. Tao et al reported g-C 3 N 4 nanoakes with a phosphorus sub-bandgap that was prepared by post-calcination treatment of buck g-C 3 N 4 with a phosphorus sub-bandgap and exhibited a strong sub-bandgap absorption over the entire visible region, enlarged surface area and improved charge separation and transfer efficiency.…”

“…These properties led to remarkably enhanced visible-light photocatalytic H 2 production. 36 Yi et al reported a combinative strategy involving hydrothermal pre-treatment and calcination to synthesize mesoporous g-C 3 N 4 with an oxygen and sulfur sub-bandgap for outstanding photocatalytic hydrogen evolution. 37 Apparently, the formation of an ordered structure along with the creation of a sub-bandgap is an effective route to further increase the photocatalytic activity of g-C 3 N 4 .…”