Constructing hierarchical ZnIn2S4/g-C3N4 S-scheme heterojunction for boosted CO2 photoreduction performance

Tubular graphitic carbon nitride (g-C3N4) photocatalyst has received considerable attention in solar to chemical energy conversion due to its appealing intrinsic photoelectrical properties and the favorable geometric configuration. However, it still suffers from severe charge recombination, which causes moderate photocatalytic performance. Herein, ZnIn2S4 nanosheets modified hexagonal g-C3N4 tubes (ZIS/HCNT) were fabricated through an in situ growth approach. By rational construction of large contact area and strong interfacial interaction, an effective Step like-scheme (S-scheme) charge transfer mode was established over ZIS/HCNT, which was confirmed by the in situ X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) analysis. Benefited from the facilitated charge separation efficiency and remained strong redox abilities, ZIS/HCNT exhibited significantly improved photocatalytic conversion rate of CO2 to CO (883 μmol h−1 g−1), which was about 13 and 2.4 times higher than that of HCNT and ZIS, respectively. This work provides a paradigm of upgrading photocatalytic CO2 reduction through a rational structural design to regulate charge transfer.