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A simultaneous application of CO 2 reduction and biomass selective oxidation within a shared photocatalytic redox system by an MoS 2 @GCN S-scheme heterojunction with rich sulfur vacancies. [Display omitted] • An Sv-rich MoS 2 @GCN S-scheme heterojunction was successfully fabricated. • CO 2 reduction and biomass refining were applied in a shared photocatalytic system. • The synergism of the Sv and S-scheme heterojunction accelerated charge transfer. • Xylonic acid and CO can be produced from liquid and gas simultaneously. Photocatalytic CO 2 reduction and biomass selective oxidation have considerable practical implications in addressing environmental challenges. However, developing efficient photocatalyst is the key to realize the mass-market applications. Herein, an MoS 2 @GCN S-scheme heterojunction, rich in sulfur vacancies (Sv), was fabricated by a dicyandiamide-blowing and calcination strategy using NH 4 Cl as the gas template. With the synergistic effects of Sv and the S-scheme charge migration mechanism, the 30%-Sv-MoS 2 @GCN demonstrated exceptional performance, showcasing a CO evolution rate of 68.3 μmol g−1 h−1 and a xylonic acid yield of 64.2%, without using any sacrificial agents. The formation of Sv was confirmed through electron paramagnetic resonance (EPR) analysis. The S-scheme charge transfer mechanism of the Sv-MoS 2 @GCN heterojunction was verified by in-situ X-ray photoelectron spectroscopy (XPS) spectra, EPR analysis, and density functional theory (DFT) calculations. This study establishes a framework for enhancing photocatalytic CO 2 reduction and biomass selective oxidation by regulating charge transfer through sensible structural design. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon nitride nanosheets ring inserted on the surface of PY53 was designed. • Lactic acid and CO can be produced from liquid and gas simultaneously. • CNs@PY53-x has good applicability for different biomass-derived feedstocks. • Lactic acid yield and CO evolution achieved 86.7% and 371.56 μmol g−1h−1. Synchronously producing gas–liquid products from biomass conversion is an effective solution for addressing global energy depletion and environmental pollution. Here, we designed an efficient photocatalyst (CNs@PY53-x) to co-produce CO and lactic acid from biomass-derived sugars. Carbon nitride nanosheets were incorporated onto the surface of PY53 using an ultrasonic-assisted self-assembly coupled with evaporation-drying strategy. The CNs@PY53-x exhibited broader visible light absorption, stronger photocurrent density, and faster separation rate of photogenerated carriers as compared with CNs or PY53. The photocatalytic performance of CNs@PY53-x correlated well with its photoelectric characterization, achieving an CO evolution rate of 371.56 μmol g−1h−1 and a lactic acid yield of 86.9% in the xylose-alkaline system. Furthermore, CNs@PY53-2 demonstrated favorable applicability with various biomass-based sugars. Poisoning experiments, coupled with electron spin resonance (ESR) characterization, revealed that the superoxide radical (O 2 −) was the primary oxidation active species during this process. This work presents a new strategy for synchronously producing gas–liquid products during biomass conversion. [ABSTRACT FROM AUTHOR]