Phosphate-modified graphitic C3N4 as efficient photocatalyst for degrading colorless pollutants by promoting O2 adsorption

The photocatalytic activity for degrading gas-phase acetaldehyde and liquid-phase phenol by graphitic carbon nitride could be greatly improved after modification with phosphoric acid, which is attributed to the clear increase in adsorbed O2 which prolongs the lifetime and enhances the separation of photogenerated charge carriers. This is based on O2 temperature-programmed desorption curves, steady-state surface photovoltage spectra, and time-resolved surface photovoltage responses.