Sonophotocatalysis of oxalic acid solution

Sonophotocatalysis of oxalic acid was performed in various atmospheric conditions. Sonophotocatalysis means a coupled reaction of sonolysis and photocatalysis. CO2, CO and H2 were obtained. The yield of CO2 was twice larger than the sum of yields of photocatalysis and sonolysis in an Ar atmosphere. Namely, synergistic effect was observed. Further improvement was observed after pre-sonication. Hydrogen peroxide produced during sonication is a key material for the synergistic effect. In surroundings including O2, however, synergistic effect could not be observed. The role of ultrasonic waves on the sonophotocatalysis of organic compounds was investigated.