Dye-Anchoring Strategy with a Metal-Organic Framework for a Highly Efficient Visible-Light-Driven Photocatalytic CO₂ Reduction through the Solid-Gas Mode

The direct solar-driven CO₂ conversion to high-value-added chemicals with high selectivity represents an attractive approach to address the energy crisis and environmental pollution. Herein, we report a facile dye-anchoring strategy with a metal-organic framework (MOF) to construct a series of low-cost visible-light-driven composite photocatalysts of rhodamine B (RhB)-sensitized Zr-MOF, x-RhB@Zr-MOF (x = 1-4). Benefiting from the coupling mode of chemical bonding rather than physical adsorption, the RhB molecules were firmly anchored in Zr-MOF, resulting in the improvement of visible-light absorption and the efficient transfer of photogenerated electrons from RhB to Zr-MOF. Significantly, 3-RhB@Zr-MOF exhibits enhanced photocatalytic performance for the reduction of CO₂ to CO under visible-light illumination. The evolution rate of CO can reach 10.27 μmol·g^-1 in 4 h and the selectivity of >99% without the use of any organic sacrificial agents or photosensitizers, much superior to that of Zr-MOF. This work provides insight that will help in the construction of selective visible-light-driven catalysts for the photoreduction of CO₂ through a solid-gas mode.