S-scheme heterojunction and dual co-catalysts on carbonized paper for biphase interface photocatalytic hydrogen production from water

Abstract

Solar-driven water splitting by photocatalysts is considered a cost-effective and environmental-friendly way to produce hydrogen fuel. However, the efficiency of hydrogen production in photocatalysis systems is still low due to the inefficient light absorption, photogenerated carrier recombination, and sluggish reaction kinetics. Here, we design and synthesize a composite carbonized paper with Co3O4/Fe2O3/g-C3N4/Au loaded on carbonized fiber (CF) by layer-by-layer assembly. Fe2O3 and g-C3N4 form an S-scheme heterojunction for enhanced interfacial charge separation. The spatially separated Co3O4 and Au co-catalysts capture photogenerated carriers and inhibit surface recombination for enhancing oxidation and reduction kinetics. In addition, composite carbonized paper floats on the water surface to form a solid-gas biphase photocatalytic interface (photothermal-generated steam/composite carbonized paper/hydrogen) with the help of the photothermal effect of composite carbonized paper. This biphase photocatalytic interface effectively reduces the transmission resistance of hydrogen and the adsorption barrier of water molecules. The CF/Co3O4/Fe2O3/g-C3N4/Au composite paper exhibits an impressive hydrogen production rate up to 78,561.51 μmol h−1 g−1. Stable loading of Co3O4/Fe2O3/g-C3N4/Au in composite paper contributes to the photocatalytic cycle. The hydrogen evolution rate in the third cycle remains 96.5 %. This work demonstrates that the combination of S-scheme heterojunction, spatially separated co-catalysts, and biphase photocatalytic interface can be a promising strategy for efficient photocatalytic platforms for solar hydrogen production.