A direct polymeric carbon nitride/tungsten oxide Z‐scheme heterostructure for efficient photocatalytic hydrogen generation via reforming of plastics into value‐added chemicals

Abstract

Abstract To promote charge transfer and separation for efficient photocatalysis, a direct Z‐scheme heterostructure was constructed by coupling polymeric carbon nitride (PCN) and WO 3 . Interestingly, the obtained PCN/WO 3 Z‐scheme heterostructure could photocatalytically produce hydrogen and value‐added chemicals (e.g., formate and acetate) by reforming of plastic polylactic acid (PLA) in alkaline aqueous condition. By optimizing WO 3 contents and reaction conditions, the obtained PCN/WO 3 heterostructure exhibits much increased photocatalytic activity for PLA photoreforming under visible light, with hydrogen evolution rate reaching 402.90 μmol·g −1 ·h −1 , which is 3.5 times that of PCN. It is revealed that the Z‐scheme charge transfer between PCN and WO 3 mainly contributes to the promoted charge separation and thus the improved photocatalytic activity. Moreover, with h + and ·OH experimentally evidenced as the predominant active species, a possible reaction pathway for the reforming of PLA into value‐added chemicals (e.g., formate and acetate) over PCN/WO 3 Z‐scheme heterostructure is cleared by monitoring the reaction intermediates and radicals. This work paves a carbon neutrality and scalable route toward the synergistical production of hydrogen and value‐added chemicals by utilizing and recycling plastic waste.