[2+1] Cycloadditions Modulate the Hydrophobicity of Ni-N4 Single-Atom Catalysts for Efficient CO2 Electroreduction

Angew Chem Int Ed Engl. 2024 May 2:e202405650. doi: 10.1002/anie.202405650. Online ahead of print.ABSTRACTMicroenvironment regulation of M-N4 single-atom catalysts (SACs) is a promising way to tune their catalytic properties toward the electrochemical CO2 reduction reaction. However, strategies that can effectively introduce functional groups around the M-N4 sites through strong covalent bonding and under mild reaction conditions are highly desired. Taking the hydrophilic Ni-N4 SAC as a representative, we report herein a [2+1] cycloaddition reaction between Ni-N4 and in-situ generated difluorocarbene (F2C:), and enable the surface fluorocarbonation of Ni-N4, resulting in the formation of a super-hydrophobic Ni-N4-CF2 catalyst. Meanwhile, the mild reaction conditions allow Ni-N4-CF2 to inherit both the electronic and structural configuration of the Ni-N4 sites from Ni-N4. Enhanced electrochemical CO2-to-CO Faradaic efficiency above 98% is achieved in a wide operating potential window from -0.7 V to -1.3 V over Ni-N4-CF2. In-situ spectroelectrochemical studies reveal that a highly hydrophobic microenvironment formed by the -CF2- group repels asymmetric H-bonded water at the electrified interface, inhibiting the hydrogen evolution reaction and promoting CO production. This work highlights the advantages of [2+1] cycloaddition reactions on the covalent modification of N-doped carbon-supported catalysts.PMID:38695268 | DOI:10.1002/anie.202405650

Source: Angewandte Chemie - May 2, 2024 Category: Chemistry Authors: Siyan Shu Tao Song Cheng Wang Hao Dai Lele Duan Source Type: research