Core–Shell β-SiC@PPCN Heterojunction for Promoting Photo-Thermo Catalytic Hydrogen Production

Abstract

Solar hydrogen production by metal-free photocatalysts represents one of the important routes to realize a low-carbon energy system. Herein, the core–shell β-silicon carbide@potassium-doped polymeric carbon nitride (β-SiC@PPCN) heterojunction with β-SiC as a core and PPCN as a shell for photo-thermo catalytic hydrogen production is developed. With such a heterojunction, not only can the H–OH bond of absorbed water be activated, but also the migration of photogenerated carriers can be promoted due to the created internal-electric-field. Owing to the excellent photothermal conversion property of β-SiC, the temperature-dependent catalytic activity is also studied. The core–shell β-SiC@PPCN heterojunction can be run at an elevated temperature upon illumination, which enhances photoinduced electron–hole separation. Density functional theory calculations demonstrate that the elevated running temperature can activate absorbed water. Remarkably, the synergy of photocatalysis and thermocatalysis makes the core–shell β-SiC-50@PPCN heterojunction yield a photo-thermo catalytic hydrogen production rate as high as 13046.7 μmol·g–1·h–1. The present study provides a promising strategy for large-scale solar hydrogen production.