Role of Heteroatoms in S,N‐Codoped Nanoporous Carbon Materials in CO 2 (Photo)electrochemical Reduction

Thiourea‐modified wood‐based activated carbon materials were evaluated as catalysts for the CO 2 electrochemical reduction reaction (CO 2 ERR). The materials obtained at 950 °C showed long‐term stability. The results indicated that thiophenic sulfur provides the catalytic activity for CO formation. However, it was not as active for CH 4 formation as was pyridinic N. Tafel plots suggested that the nanoporous structure enhanced the kinetics for CO 2 reduction. The electric conductivity limited the activity for CO 2 ERR in the materials modified at 600, 800, and 900 °C. The effect of visible light on CO 2 ERR was also investigated in this study. Upon irradiation, photocurrent was generated, and the current density increased during the CO 2 reduction process. Combined with a band‐gap alignment, the results indicate that thiophenic S in the carbon matrix contributed to the sample's photoactivity in visible light. These species enhance the overall reduction process, promoting both the hydrogen evolution reaction and CO 2 reduction to CO.