Photo-plasma relay catalysis for molecular oxygen activation

Clean energy driven molecular oxygen activation (MOA) is crucial for the advancement of green oxidation technology and sustainable chemistry. While photocatalysis and plasma catalysis have long been regarded as promising green means for MOA, it remains largely unexplored by which mechanism these two processes can be combined to surpass the capability of each individually for efficient MOA. In this study, we couple photocatalysis with solution plasma catalysis by using oxides suspensions as the mediator, and elucidate the specific relay mechanism of photo-plasma catalysis for MOA. Among the various oxides tested, TiO₂ with an anatase–rutile mixed composition performs the best for photocatalysis-solution plasma synergy, resulting in 11.3 times and 5.6 times higher rate of oxidative decomposition of bisphenol A than that of photocatalysis and plasma catalysis alone, respectively. The solution plasma in synergy with UV excitation boosts the yield of ·O₂^– on rutile TiO₂ and the conversion of ·O₂^– to ¹O₂ on anatase TiO₂, thereby promoting a relay MOA at the anatase–rutile interface. Our findings on the relay mechanism of MOA and the promotion of synergy by the heterojunction interface open new avenues for clean energy driven catalytic reaction with heterojunction materials.