Microstructure Induced Thermodynamic and Kinetic Modulation to Enhance CO2 Photothermal Reduction: A Case of Atomic-Scale Dispersed Co–N Species Anchored Co@C Hybrid

The transformation of CO2 into a single product is a critical scientific challenge because of the difficulty associated with targeted activation and conversion of CO2 by heterogeneous catalysts. Herein, we present an atomic-scale dispersed Co–N species anchored Co@C hybrid structure (entitled as Co@CoN&C) that regulates catalytic properties in thermodynamic and kinetic processes to achieve active and highly selective CO yield in the photothermal CO2 reduction. An optimal sample delivers the maximum yield rate of 132 mmol gcat.–1 h–1 and remarkable CO selectivity (91.1%), while the undesirable methanation activity, compared with typical Co nanoparticles (NPs), was suppressed. The mechanism study suggests that the strong photon–matter interaction over graphitic-carbon and Co NPs can enhance the light-to-heat conversion efficiency and thus induce the high work temperature, which is thermodynamically beneficial for CO2 activation and subsequently promoted the catalytic activity. Furthermore, the carbon layers improve the adsorption of CO2, and the surface atomically dispersed Co–N species weakens hydrogenation capability, which kinetically controls the reaction pathway and therefore attains the high selectivity for CO production. This study exemplifies that the microstructure design can modulate the thermodynamic and kinetic factors of photochemical reaction and thereby achieve potential solar-to-chemical energy conversion.