Fabricating a CNIS@SL S-Scheme Heterojunction with Spatial Charge Separation for Boosting Photocatalytic Biomass Reforming

Cooperative coupling of energy fuel production with high-value organic acid synthesis is promising in photocatalytic reforming. Nonetheless, there are few reports on the enhancement of biomass conversion with an S-scheme heterojunction. Herein, we have employed a bottom-up strategy to develop a nonprecious metal S-scheme heterojunction (CNIS@SL) for efficiently converting hemicellulose-derived feedstocks into CO and xylonic acid. Under the synergistic effects of Ni element doping, an S-scheme heterojunction, and a biochar network, this system achieved a CO release rate of 1130.0 μmol g–1 h–1 and 62.4% of xylonic acid. Electron spin resonance analysis, supplemented by poisoning tests, identified holes (h+) as the predominant active species in the reaction mechanism. In situ irradiation X-ray photoelectron spectroscopy further confirmed that electrons transfer directly from the conduction band of the CIS to the valence band of NIS under the action of an internal electric field. These findings offer fresh perspectives on designing an S-scheme heterojunction for highly efficient biomass reforming.