Pyridine Grafted on SnO2 -Loaded Carbon Nanotubes Acting as Cocatalyst for Highly Efficient Electroreduction of CO2.

Sn-based electrocatalysts have shown great potential in the future industrial application of CO2 electroreduction (CO2 ER) to C1 products due to their non-toxicity and low price. However, it is a great challenge to fabricate a Sn-based electrocatalytic system with high performance and stability. Herein, grafted pyridine was innovatively coupled with SnO2 to construct an organic-inorganic composite (SnO2 /Py-CNTO) for highly efficient CO2 ER. The detailed studies showed that pyridine and protonated pyridine coexist on the surface of SnO2 /Py-CNTO, and both play distinctive roles in promoting the selectivity of CO2 ER. Benefiting from the merits, SnO2 /Py-CNTO delivered an excellent faradaic efficiency (FE) of 96 % for CO2 ER at -1.29 VRHE where the HCOOH production with 85 % FE dominated, and good stability for 32 h electrolysis. The theoretical calculations showed that protonated pyridine not only facilitates the CO2 adsorption and HCOOH desorption, but also significantly reduces the limiting potential for the conversion of CO2 to HCOOH.