Enhancing biomass oxidation with carbon nitride nanosheets ring inserted on C. I. Pigment Yellow 53 photocatalysts for simultaneous CO and lactic acid production

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 (O2−) was the primary oxidation active species during this process. This work presents a new strategy for synchronously producing gas–liquid products during biomass conversion.