Heterogeneous Cobalt Phthalocyanine/Sulfur-Modified Hollow Carbon Sphere for Boosting CO2 Electroreduction and Zn–CO2 Batteries

Tuning coordination environment of single-atom catalysts (SACs) is widely applied for the electrochemical CO 2 reduction reaction (CO 2 RR). However, the influence of the interaction between SACs and support on the catalytic performance are not comprehensive. Herein, taking cobalt phthalocyanine (CoPc) as a conceptual example, a hetero S-atom doping strategy of hollow carbon sphere (S-NHC) is put forward as a carrier, revealing the intrinsic relationship between microenvironment regulation and catalytic activity of single Co-atom. The additional S doping may induce more carbon defect and increases the content of pyrrolic N in the S-NHC sample, leading to stronger electronic interaction of heterogeneous CoPc/S-NHC for boosting CO 2 RR performance. Remarkably, the catalyst achieves a highest CO selectivity of nearly 100% at −0.6 V, and the FE CO are over 90% in a wide potential range from −0.4 to −0.8 V in a flow cell. The maximum power density is high as 2.68 mW cm −2 at 4.7 mA cm −2 for the Zn–CO 2 battery with CoPc/S-NHC cathode. In situ attenuated total reflection infrared (ATR-IR) spectroscopy reveals the formation of key *COOH and *CO intermediates, while the calculation result confirm the optimized Gibbs free energy of these intermediates on CoPc/S-NHC, suggesting the feasibility of the regulation strategy.