Synthesis of coralloid carbon nitride polymers and photocatalytic selective oxidation of benzyl alcohol

Abstract

Polymeric carbon nitride (C3N4) is currently the most potential nonmetallic photocatalyst, but it suffers from low catalytic activity due to rapid electron–hole recombination behavior and low specific surface area. The morphology control of C3N4 is one of the effective methods used to achieve higher photocatalytic performance. Here, bulk, lamellar and coralloid C3N4 were synthesized using different chemical methods. The as-prepared coralloid C3N4 has a higher specific surface area (123.7 m2 · g−1) than bulk (5.4 m2 · g−1) and lamellar C3N4 (2.8 m2 · g−1), thus exhibiting a 3.15- and 2.59-fold higher photocatalytic efficiency for the selective oxidation of benzyl alcohol than bulk and lamellar C3N4, respectively. Optical characterizations of the photocatalysts suggest that coralloid C3N4 can effectively capture electrons and accelerate carrier separation, which is caused by the presence of more nitrogen vacancies. Furthermore, it is demonstrated that superoxide radicals (·O2 −) and holes (h+) play major roles in the photocatalytic selective oxidation of benzyl alcohol using C3N4 as a photocatalyst.