Cobalt-Doped MoS2-Integrated Hollow Structured Covalent Organic Framework Nanospheres for the Effective Photoreduction of CO2 under Visible Light

Photocatalytic conversion of CO2 into beneficial raw chemicals has gained a great deal of attention for well over the recent decade due to its prospect for alleviating energy scarcity and global warming. Even though photocatalytic CO2 reduction technique has shown great promise, the successful conversion of CO2 to the intended outputs has remained a key barrier. Here, we present the design synthesis of a hollow nanospherical keto-enamine TpPa-1 covalent organic framework (COF) integrated single-atom Co-1T-MoS2 (TpPa-1/Co-1T-MoS2) composite with the appropriate band edge potential and an enhanced charge separation to improve its CO2 photoreduction efficiency under visible light irradiation. With a selectivity of 93%, the developed TpPa-1/Co-1T-MoS2 nanocomposite exhibits impressive photocatalytic CO2 reduction efficiency of up to ∼196 μmol g–1 h–1 of CO. Bare TpPa-1 and Co-1T-MoS2 both had around 1.23 and 1.6 times lower CO than TpPa-1/Co-1T-MoS2. Parametric analyses show that the TpPa-1 and Co-1T-MoS2 counterparts have a remarkable cumulative influence on the specificity and efficacy of photoreduction of CO2 to CO. TpPa-1/Co-1T-MoS2 composite is one of the handful of notable values cited in the literature, with an apparent quantum yield of 0.7% at 420 nm under ideal conditions. 13C labeling confirms that the selective conversion of CO2 to CO was facilitated by couplings between TpPa-1 and Co-1T-MoS2, which enhanced charge separation and migration to the surface. The findings show that COFs and their single-atom-based composites can be developed for next-generation photocatalytic systems and that this technology may also be interesting for other energy conversion applications.