Promoting the generation of hydroxyl radicals to improve the photocatalytic toluene oxidation: A combined strategy of morphology regulation and layered double hydroxide assistance

Hydroxyl radical is one of critical active species in photocatalytic VOCs oxidation. The H 2 O dissociation assisted with holes is an important and direct path for generating ·OH radicals. Nevertheless, the design of active sites for H 2 O dissociation is still lacked, and a strategy of simultaneously improving charge separation and H 2 O dissociation to generate ·OH radicals is urgently demanded. Herein, a combined strategy of morphology regulation and layered double hydroxide (LDH) assistance was proposed to promote ·OH radical generation and the designed Co 3 O 4 /LDH catalyst was constructed for photocatalytic toluene oxidation. The spindle morphology of Co 3 O 4 with small size shortened electron transfer distance and promoted charge separation. The assistance of LDH further promoted electron transfer and provided edge hydroxyl sites for H 2 O dissociation. The optimal Co 3 O 4 /LDH showed toluene degradation efficiency of 85.19%, which was 2.3 and 1.3 times than those of LDH and Co 3 O 4 . These findings offer a valuable insight into catalyst design for photocatalytic VOCs oxidation.