Interfacial engineering of metallic rhodium by thiol modification approach for ambient electrosynthesis of ammonia

Here we report a vapor-phase reaction approach to fabricate rhodium(I)-dodecanethiol complex coated on carbon fiber cloth (Rh(I)-SC₁₂H₂₅/CFC), followed by low-temperature pyrolysis to achieve dodecanethiol modified Rh (Rh@SC₁₂H₂₅/CFC) for electrocatalytic nitrogen reduction reaction (NRR). The results demonstrate that after pyrolysis for 0.5 h at 150 °C, the obtained Rh@SC₁₂H₂₅/CFC-0.5 exhibits excellent NRR activity with an NH₃ yield rate of 121.2 ± 6.6 µg∙h⁻¹∙cm⁻² (or 137.7 ± 7.5 µg∙h⁻¹∙mg_Rh⁻¹) and a faradaic efficiency (FE) of 51.6% ± 3.8% at −0.2 V (vs. RHE) in 0.1 M Na₂SO₄. The theoretical calculations unveil that the adsorption of dodecanethiol on the hollow sites of Rh(111) plane is thermodynamically favorable, effectively regulating the electronic structure and surface wettability of metallic Rh. Importantly, the dodecanethiol modification on Rh(111) obviously decreases the surface H* coverage, thus inhibiting the competitive hydrogen evolution reaction and concurrently reducing the electrocatalytic NRR energy barrier.