Manipulating photogenerated electron flow in nickel single-atom catalysts for photocatalytic CO2 reduction into tunable syngas

The key to designing photocatalysts is to orient the migration of photogenerated electrons to the target active sites rather than dissipate at inert sites. Herein, we demonstrate that the doping of phosphorus (P) significantly enriches photogenerated electrons at Ni active sites and enhances the performance for CO₂ reduction into syngas. During photocatalytic CO₂ reduction, Ni single-atom-anchored P-modulated carbon nitride showed an impressive syngas yield rate of 85 μmol g_cat⁻¹ h⁻¹ and continuously adjustable CO/H₂ ratios ranging from 5:1 to 1:2, which exceeded those of most of the reported carbon nitride-based single-atom catalysts. Mechanistic studies reveal that P doping improves the conductivity of catalysts, which promotes photogenerated electron transfer to the Ni active sites rather than dissipate randomly at low-activity nonmetallic sites, facilitating the CO₂-to-syngas photoreduction process.