Artificial Chlorophyll-like Structure for Photocatalytic CO2 Chemical Fixation

Abstract

In nature, green leaves accomplish photosynthesis via chloroplasts, where the Mg-N₄ centered chlorophyll and enzymes undertake light absorption and catalytic reaction, respectively. This intriguing phenomenon inspires us to design an artificial photosynthetic system that synergizes these dual attributes, a field that has remained largely unexplored. Herein, we develop a highly stable artificial chlorophyll-like nitrogen-decorated amorphous carbon material (Mg-NC) featuring abundant Mg-N₄ moieties (with high Mg content reaching ≈ 9.2 wt%), which simultaneously integrates the light-absorption center and reaction center to mimic natural photosynthesis of CO₂ valorization. As demonstrated, taking photocatalytic CO₂ cycloaddition reaction as an example, the Mg-N₄ active center in Mg-NC plays as an electronic donor, which can readily inject hot electrons to the adsorbed substrates, resulting in the swift formation of cyclic carbonate products. Remarkably, the as-designed Mg-NC exhibited outstanding photocatalytic CO₂ cycloaddition performance, achieving an impressive reaction rate up to 9.67 mmol·g^-1·h^-1 under mild conditions, which could be kept even under gram scale conditions. Our study offers an artificial biomimetic enzyme heterogeneous photocatalysts for CO₂ valorization.

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