Coupling of Cu Catalyst and Phosphonated Ru Complex Light Absorber with TiO2 as Bridge to Achieve Superior Visible Light CO2 Photoreduction

Solar-driven CO2-to-ethanol conversion enabled by continuous CO2 transport via a superhydrophobic Cu2O nano fence

The overall photocatalytic CO2 reduction reaction presents an eco-friendly approach for generating high-value products, specifically ethanol. However, ethanol production still faces efficiency issues (typically formation rates <605 μmol g-1 h-1). One significant challenge arises from the difficulty of continuously transporting CO2 to the catalyst surface, leading to inadequate gas reactant concentration at reactive sites. Here, we develop a mesoporous superhydrophobic Cu2O hollow structure (O-CHS) for efficient gas transport. O-CHS is designed to float on an aqueous solution and act as a nano fence, effectively impeding water infiltration into its inner space and enabling CO2 accumulation within. As CO2 is consumed at reactive sites, O-CHS serves as a gas transport channel and diffuser, continuously and promptly conveying CO2 from the gas phase to the reactive sites. This ensures a stable high CO2 concentration at reactive sites. Consequently, O-CHS achieves the highest recorded ethanol formation rate (996.18 μmol g-1 h-1) to the best of our knowledge. This strategy combines surface engineering with geometric modulation, providing a promising pathway for multi-carbon production.

Well-defined Co9S8 cages enable the separation of photoexcited charges to promote visible-light CO2 reduction

Exploring affordable cocatalysts with high performance for boosting charge separation and CO₂ activation is an effective strategy to reinforce CO₂ photoreduction efficiency. Herein, well-defined Co₉S₈ cages are exploited as a nonprecious promoter for visible-light CO₂ reduction. The Co₉S₈ cages are prepared via a multistep strategy with ZIF-67 particles as the precursor and fully characterized by physicochemical techniques. The hollow Co₉S₈ cocatalyst with a high surface area and profuse catalytically active centers is discovered to accelerate separation and transfer of light-induced charges, and strengthen concentration and activation of CO₂ molecules. In a hybrid photosensitized system, these Co₉S₈ cages efficiently promote the deoxygenative reduction of CO₂ to generate CO, with a high yield rate of 35 μmol h^-1 (i.e., 35 mmol h^-1 g^-1). Besides, this cocatalyst is also of high stability for the CO₂ photoreduction reaction. Density functional theory (DFT) calculations reveal that the Ru(bpy)₃²⁺ photosensitizer is strongly absorbed on the Co₉S₈ (311) surface through forming four Co-C bonds, which can serve as the "bridges" to ensure quick electron transfer from the excited photosensitiser to the active Co₉S₈ cocatalyst, thus promoting the separation of photoexcited charges for ehannced CO₂ reduction performance.

Green light (550 nm) driven tunable syngas synthesis from CO2 photoreduction using heterostructured layered double hydroxide/TiC photocatalysts

Under visible light, LDH/TiC photocatalysts were prepared and exhibited tunable syngas synthesis with different CO/H2 ratios.