Revealing interaction of pyridinic N in N-doped carbon with Sn sites for improved CO2 reduction

N-doped carbon (NC) materials have emerged as attractive supports for metal-based catalysts, enhancing their catalytic performance through the metal–support interactions. However, gaining fundamental insights into the metal–support interaction between NC support and Sn metal sites for improving the electrocatalytic CO₂ reduction reaction (CO₂RR) performance remains challenging. Here, we reveal that pyridinic N in NC support indirectly induces the net electron distribution of Sn sites to exhibit optimal adsorption of HCOO* and HCOOH* by combining theoretical simulations and experiments, while pyrrolic N and graphitic N present weaker adsorption of HCOO* and stronger adsorption of HCOOH*, respectively. Consequently, the catalyst comprising NC with abundant pyridinic N loaded SnO₂ quantum dots exhibits excellent CO₂RR performance, achieving high partial formate activity (over 90 mA. cm⁻² in an H-cell and 200 mA. cm⁻² in a flow cell) and impressive Faradaic efficiency for formate (approximately 90%). This work provides valuable insights into intricate metal–support interactions, thereby offering guidance for the future design and development of CO₂RR electrocatalysts.

Graphical abstract