Critical Optimization of Phosphorus Functionalized Carbon Nanomaterials for Metal-Free Solar Hydrogen Production and Simultaneous Organic Transformation

摘要

Complete metal-free P-functionalized carbon nanomaterials are synthesized from a single molecular precursor, phytic acid, for photocatalytic solar H-2 production and simultaneous organic transformation of 4-methyl benzyl alcohol to 4-methyl benzaldehyde by managing the complete redox cycle. It is observed that by increasing the carbonization time, P-functionalized amorphous carbon dots convert to the highly defined 2D sheet-like nanostructure with optimum P-functionality, resulting in efficient light absorption, charge separation, and improved active sites for photocatalysis. Finally, the highly defined sheet-like structure converts to a more defected aggregated form, resulting in the depletion of photocatalytic efficiency. The structural and elemental features are further correlated with the ongoing photophysics by means of steady-state and time-resolved fluorescence spectroscopy. Transient photocurrent responses and Mott-Schottky plots directly support the optimization of P-functionalized carbon nanostructure for efficient photocatalysis. Finally, the detailed computational studies are carried out to unveil the charge separation mechanism and the crucial role of P-functionalities as active sites for better charge accumulation as well as H2O adsorption on the surface. Overall, the in-depth structure-property correlation and critical optimization of the heteroatom functionalized carbon nanomaterials will open up new possibilities for further development of metal-free photocatalysts for solar-energy conversion devices.