Effect of alkali metal cation doping in graphitic carbon nitride towards photocatalytic generation of hydrogen peroxide under direct sunlight

H2O2, a powerful oxidant with a vast number of industrial applications, is being synthesized by the energy intensive anthraquinone process. Recently, H2O2 has been synthesized using H2O and O2 by photocatalysis. Graphitic carbon nitride (g-C3N4) is a popular low-cost photocatalyst that is known to produce H2O2. However, the properties g-C3N4 needs to be tailored to improve the yield of H2O2. We discuss such a modification of g-C3N4 by alkali metal cation doping. Among the Li+, Na+ and K+ ions, doping of 10 wt% of K+ in g-C3N4 increase the yield of H2O2 (200 μmol g−1 h−1) by 2.5 times as compared un-doped g-C3N4 under natural sunlight.