An enhanced electrochemical CO2 reduction reaction on the SnOx–PdO surface of SnPd nanoparticles decorated on N-doped carbon fibers

Abstract

In the electrocatalytic CO₂ reduction reaction (CO₂RR), tin-based catalysts are known for their high formate faradaic yield. However higher overpotentials are required to attain a high faradaic yield with high partial current density for formate. Here, we describe the increase in the electrocatalytic CO₂RR activity of Sn nanoparticles decorated on nitrogen-doped carbon fibers (NCFs) by adding a small amount of Pd. Nitrogen-doped carbon fibers decorated with SnPd nanoparticles (Sn_100−yPd_y–NCF) of different Sn : Pd ratios were synthesized using the electrospinning method and their electrocatalytic CO₂RR activity was studied. The Sn_100−yPd_y–NCF catalyst with 3 wt% (y = 3) Pd displayed superior activity for the CO₂RR and attained a faradaic efficiency of 85%, whereas the NCF with Sn nanoparticles (Sn₁₀₀–NCF) attained only 57% efficiency at the same potential. The surface electronic configuration, Tafel slope (79 mV dec⁻¹) and bicarbonate reduction activity of the catalyst reveal that the combination of SnO_x–PdO on the catalyst surface is responsible for the superior CO₂RR activity.