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

Graphical Composite catalyst : Axially grafted pyridine is successfully coupled with SnO 2 nanoparticles to construct the organic-inorganic composite catalyst SnO 2 /Py-CNTO for highly efficient electroreduction of CO 2 . SnO 2 /Py-CNTO delivers an excellent faradaic efficiency (FE) of 96 % for CO 2 ER at −1.29 V RHE where the HCOOH production with 85 % FE dominates, and good stability for 32 h electrolysis. Sn-based electrocatalysts have shown great potential in the future industrial application of CO 2 electroreduction (CO 2 ER) to C 1 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 SnO 2 to construct an organic-inorganic composite (SnO 2 /Py-CNTO) for highly efficient CO 2 ER. The detailed studies showed that pyridine and protonated pyridine coexist on the surface of SnO 2 /Py-CNTO, and both play distinctive roles in promoting the selectivity of CO 2 ER. Benefiting from the merits, SnO 2 /Py-CNTO delivered an excellent faradaic efficiency (FE) of 96 % for CO 2 ER at −1.29 V RHE 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 CO 2 adsorption and HCOOH desorption, but also significantly reduces the limiting potential for the conversion of CO 2 to HCOOH.