Tunable CO2-to-syngas conversion via strong electronic coupling in S-scheme ZnGa2O4/g-C3N4 photocatalysts

The conversion of CO2 into syngas, a mixture of CO and H-2, via photocatalytic reduction, is a promising approach towards achieving a sustainable carbon economy. However, the evolution of highly adjustable syngas, particularly without the use of sacrifice reagents or additional cocatalysts, remains a significant challenge. In this study, a step-scheme (S-scheme) 0D ZnGa2O4 nanodots (similar to 7 nm) rooted g-C3N4 nanosheets (denoted as ZnGa2O4/g-C3N4) heterojunction photocatalyst was synthesized vis a facial insitu growth strategy for efficient CO2-to-syngas conversion. Both experimental and theoretical studies have demonstrated that the polymeric nature of g-C3N4 and highly distributed ZnGa2O4 nanodots synergistically contribute to a strong interaction between metal oxide and C3N4 support. Furthermore, the desirable S-scheme heterojunction in ZnGa2O4/g-C3N4 efficiently promotes charge separation, enabling strong photoredox ability. As a result, the S-scheme ZnGa2O4/g-C3N4 exhibited remarkable activity and selectivity in photochemical conversion of CO2 into syngas, with a syngas production rate of up to 103.3 mu mol g(-1) h(-1), even in the absence of sacrificial agents and cocatalyst. Impressively, the CO/H-2 ratio of syngas can be tunable within a wide range from 1:4 to 2:1. This work exemplifies the effectiveness of a meticulously designed S-scheme heterojunction photocatalyst for CO2-to-syngas conversion with adjustable composition, thus paving the way for new possibilities in sustainable energy conversion and utilization.

Automated summary

In this study, a novel S-scheme heterojunction photocatalyst was synthesized for efficient CO2-to-syngas conversion. The photocatalyst showed remarkable activity and selectivity in the conversion of CO2 to syngas, even without the use of sacrifice reagents or additional cocatalysts.