Dual-Oxidative Co-Catalyst Synergy Regulating Charge Transport Cascade for Enhanced CO₂ Photocatalysis

Converting CO₂ into high-value hydrocarbons through solar-driven heterogeneous photocatalysis is deemed a salient technological avenue for achieving carbon neutrality, while confronting arduous challenges, which include the severe photogenerated charge carrier recombination and sluggish charge transfer kinetics. Herein, we propose an ingenious strategy of "synergistic dual-oxidative co-catalyst regulation" to customize the unidirectional cascade charge transfer pathway for enhanced photocatalytic CO₂ reduction catalysis. By progressively assembling an oxygen-containing cobalt sulfide (CoSOH) and a layered double hydroxide (LDH) dual hole-trapping mediators onto the CdIn₂S₄ framework, we design a CdIn₂S₄/CoSOH/LDH ternary artificial photosystem, in which the CoSOH interlayer serves as a highway for charge transport relay, markedly accelerating the directional hole migration, while the CoAl-LDH acts as a terminal hole reservoir engendering a synergistic hole-relay mechanism. This dual-oxidative-cocatalyst-driven hole modulation strategy significantly enhances the charge separation/transfer and optimizes the surface reaction kinetics through the hole transport relay, considerably boosting the photocatalytic CO₂ reduction activity. Our work affords a quintessential paradigm for strategically designing artificial photocatalysts with finely tuned spatial charge motion toward efficient solar-to-fuel conversion.