Metal-free N–S co-doped electrode for electrochemical CO2 reduction to HCOOH.

This paper presents metal-free N–S co-doped catalysts that synthesize in the presence of different S sources such as thiourea and polythiophene (Ptyf). The composition, morphology, and structure of the obtained sample are measured by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), Brunauer–Emmett–Teller (BET) method, X-ray diffraction (XRD), UV–vis spectroscopy, Fourier transform ınfrared-attenuated total reflection spectroscopy (FTIR-ATR), and X-ray photoelectron spectroscopy (XPS). Although the characterization measurements showed that the fabricated catalysts had a similar elemental composition, the polythiophene-based catalysts retained their polymer properties such as active surface area, conductivity, and conjugated chains. This result enhances the adsorption of CO2 to the catalyst surface and promotes the reduction of CO2 effectively. The only product is HCOOH with a faradaic efficiency of 84% which was achieved on P-N/S2-rGO (P: pyrolysis) at -0.6 V (Ag/AgCl). [ABSTRACT FROM AUTHOR]