Engineering the surface delocalized electrons facilitates the ring-opening for deep toluene oxidation

• Delocalized electrons were formed on Bi 2 O 2 CO 3 surface by interlayer hydrogenation. • Stable conjugated structure of benzene-ring was tailored, resulting in destabilization. • Direct ring-opening pathway and deep toluene oxidation were achieved. • The reaction pathway of reactants with un-activated benzene-ring was revealed. The stable conjugated structure of benzene-ring poses the persistent challenge for deep oxidation of toluene. In this study, the electronic structure of benzene-ring-containing reactants is tailored by engineering the interlayer hydrogenation in layered Bi 2 O 2 CO 3 , where charge separation and migration capabilities are improved and the confined charge in the interlayer and intralayer could transfer to catalyst surface and serve as delocalized electrons. The ring-opening site, the C = C bond, is activated by delocalized electrons. Consequently, the conjugated structure of the benzene-ring turns into a state with uneven charge distribution, resulting in weakened stability. With the attack of photo-generated radicals, the destabilized benzene-ring structure can be destroyed with direct ring-opening of toluene and achieves deep oxidation of toluene. Therefore, the degradation and mineralization of photocatalytic toluene are improved with great stability and humidity adaptability. This concept of promoting ring-opening with delocalized electrons provides a new strategy for the development of high-performance photocatalyst.