Understanding Structure‐Activity Relationship in Pt‐loaded g‐C3N4 for Efficient Solar‐ Photoreforming of Polyethylene Terephthalate Plastic and Hydrogen Production

Abstract

AbstractCoupling the hydrogen evolution reaction with plastic waste photoreforming provides a synergistic path for simultaneous production of green hydrogen and recycling of post‐consumer products, two major enablers for establishment of a circular economy. Graphitic carbon nitride (g‐C3N4) is a promising photocatalyst due to its suitable optoelectronic and physicochemical properties, and inexpensive fabrication. Herein, a mechanistic investigation of the structure‐activity relationship of g‐C3N4 for poly(ethylene terephthalate) (PET) photoreforming is reported by carefully controlling its fabrication from a subset of earth‐abundant precursors, such as dicyandiamide, melamine, urea, and thiourea. These findings reveal that melamine‐derived g‐C3N4 with 3 wt.% Pt has significantly higher performance than alternative derivations, achieving a maximum hydrogen evolution rate of 7.33 mmolH2 gcat−1 h−1, and simultaneously photoconverting PET into valuable organic products including formate, glyoxal, and acetate, with excellent stability for over 30 h of continuous production. This is attributed to the higher crystallinity and associated chemical resistance of melamine‐derived g‐C3N4, playing a major role in stabilization of its morphology and surface properties. These new insights on the role of precursors and structural properties in dictating the photoactivity of g‐C3N4 set the foundation for the further development of photocatalytic processes for combined green hydrogen production and plastic waste reforming.