Cyano group modified graphitic carbon nitride supported Ru nanoparticles for enhanced CO2 methanation

[Display omitted] •Cyano group promotes moderate CO2 adsorption.•Electronic-rich Ru nanoparticles promotes H2 activation.•Cyano group switches the CO2 hydrogenation reaction pathway.•Synergistic effect of cyano group and Ru nanoparticles promote CO2 hydrogenation. Graphitic carbon nitride (g-C3N4) based materials has been widely used for catalytic CO2 hydrogenation reaction. However, the catalytic activity is restricted due to the barren active sites and the weak ability to activate CO2 for the traditional g-C3N4. We demonstrate here that cyano group modified g-C3N4 supported Ru nanoparticles exhibits high activity and selectivity for CO2 methanation. The introduction of cyano group promotes the formation of medium basic sites for enhanced CO2 adsorption. Meanwhile, the formation of electron-rich Ru nanoparticles with the assistance of cyano group boosts the H2 activation. The synergistic effect of cyano group and Ru nanoparticles improves catalytic performance up to 14 times. Characterizations prove that cyano group with electron-withdrawing properties influences the way of CO2 adsorption via electron transfer and changes the CO2 hydrogenation reaction pathway. This work provides a new insight into the switching of CO2 hydrogenation pathway and enhanced catalytic activity via surface functional groups modification of g-C3N4 based catalyst.