G-C3N4 sheet nanoarchitectonics with island-like crystalline/amorphous homojunctions towards efficient H2 and H2O2 evolution

Photocatalystic evolution of H2O2 from water and oxygen has attracted significant attention because of envi-ronmentally friendly. The absorption in visible and hydrophilic feature of graphitic carbon nitride (g-C3N4) make it a good candidate. In this paper, a rapid post-treatment at high temperature was developed to obtain g-C3N4 nanosheets with abundant crystalline/amorphous interfaces to form homojunctions, which optimized uniplanar carrier mobility dynamics. The conversion from bulk to two-dimensional g-C3N4 resulted from the breakage of interplanar hydrogen bonds and interlayer Van der Waals force. The unique morphology not only rendered photocatalyst with larger specific surface area but also inhibited the robust volume recombination of charge carriers. The accelerated charge carriers flow at the interface, interplane and interlayer together ameliorated the separation and transfer of electrons and holes. A new-emerged n & RARR;& pi;* transition ameliorated the poor light uti-lization efficiency. Beyond the increased photocatalytic H-2 evolution property (779.2 mu mol g(-1) h(-1)), optimized sample displayed a H2O2 evolution activity as high as 4877.1 mu Mg- 1 h(-1) under visible light illumination, which was similar to 5.8 times of that of bulk g-C3N4. Detailed photocatalytic mechanism investigation manifested that the two-step single-electron oxygen reduction process occupied the dominant status in H2O2 evolution. This work pro-posed a novel strategy for obtaining g-C3N4 homojunctions as a promising bi-functional metal-free catalyst to be applied in clean energy production field.

Automated summary

In this study, g-C3N4 nanosheets with abundant crystalline/amorphous interfaces were obtained by a rapid post-treatment at high temperature. This optimized the carrier mobility dynamics, enhanced the separation and transfer of charge carriers, and improved the photocatalytic properties of H2O2 and H2.