Construction of a P, N Co-Doped Nanocarbon-Embedded g-C3N4 Hollow Sphere Nanoreactor for the Efficient Photocatalytic Production of Hydrogen Peroxide

The photocatalytic production of hydrogen peroxide (H2O2) by graphitic carbon nitride (g-C3N4) has been a promising technique. However, its photocatalytic property is limited by the easy combination of photogenerated charges, low reaction selectivity, and reaction rate in the O2 reduction reaction (ORR) process. Hence, a photocatalytic nanoreactor system is designed and constructed by embedding the P, N co-doped carbon nanomaterials in a g-C3N4 hollow sphere. The P, N co-doped nanocarbon as an acceptor and transporter for photo-generated electrons can inhibit the combination of photogenerated carriers with electron transfer from CNHS to P, N–C. Particularly, the P, N co-doped carbon active sites are beneficial to improve two-electron (2 e–) ORR selectivity with favorable formation of hydroperoxo species (−OOH). With the promoted electron transfer and 2 e– ORR selectivity for H2O2 production in the confinement domain of the hollow sphere interior, the resultant photocatalytic system exhibits a high production rate towards H2O2 of 239.5 μmol h–1 g–1 in pure water and 4568 μmol h–1 g–1 with isopropanol hole scavenger, which is 14.1 and 35.7 times those of bulk g-C3N4. This study offers an efficient avenue for the construction and improvement of photocatalysts and an insight into the understanding of photocatalytic H2O2 production.