Carbon Dioxide Synergized Photo‐Reforming for Efficient Valorization of Bio‐Polyols With a Dynamic Carbon Balance

ABSTRACT

Photocatalytic upgrading of biomass‐derived feedstocks into value‐added chemicals is promising for carbon neutrality but limited by low carbon utilization and CO ₂ emissions from over‐oxidation. Herein, we establish a “self‐feeding” photocatalytic system coupling glycerol oxidation with concurrent CO ₂ photoreduction to seamlessly close the carbon loop, enabling a truly dynamic and emission‐free biomass valorization strategy. This design uses defect‐engineered metal‐organic frameworks (MOFs) with atomically anchored Cu sites to synergistically activate glycerol and O ₂ and introduce CO ₂ to steer the evolution of reactive oxygen species, thereby tempering hydroxyl radicals (•OH) for selective oxidative cleavage. Under illumination, CO ₂ coordination with in situ formed Cu ^I sites facilitates CO ₂ photoreduction and dictates chemo‐selective C–C scission via decarbonylation to avoid over‐oxidation. By kinetically matching CO ₂ release with in situ reduction, the system channels liberated carbon exclusively into value‐added C ₁ products, achieving both carbon yield and selectivity approaching ∼100%. Benchmark production rates reach 2875 µmol g ⁻¹  h ⁻¹ for CO and 1185 µmol g ⁻¹  h ⁻¹ for HCOOH (corresponding to ∼3.0 carbons per glycerol molecule), culminating in a strictly zero‐CO ₂ ‐emission process. This work resolves the classic trade‐off between oxidation depth and carbon retention and reframes CO ₂ as a functional reaction modulator, charting a viable paradigm for carbon‐neutral chemical synthesis.