Band alignment of homojunction by anchoring CN quantum dots on g-C3N4 (0D/2D) enhance photocatalytic hydrogen peroxide evolution

Polymeric carbon nitride (C 3 N 4 ) is a very attractive candidate to produce photocatalytic hydrogen peroxide (H 2 O 2 ) due to its low-cost, metal-free characteristics. However, the low efficiency would limit its development to higher yields because of insufficient light absorption and electron-hole separation. Here, we developed a simple method to anchor CN quantum dots (QDs) onto g-C 3 N 4 nanosheets to form a homojunction structure (HJ-C 3 N 4 ), which could improve photocatalytic performance largely without introducing metal elements. Its superior efficiency is a result of the band alignment by the homojunction structure providing excellent electron-hole separation and QDs providing suppressed recombination. Simultaneously, the light responsiveness of QDs endows a wide spectrum-responsive adsorption and enhances the adsorption intensity. The H 2 O 2 yield of the HJ-C 3 N 4 reached 115 μmol L −1 h −1 in pure water by visible light, which has an 8.6x higher production than g-C 3 N 4 nanosheets . The material design of 0D/2D homojunction could be extended to other materials with specific band alignment.