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

Figure 1 (a) Schematic illustration of the fabrication process of Rh@SC12H25/CFC-x catalysts. (b) TGA and derivative TGA curves of Rh(I)-SC12H25/CFC. (c) XRD patterns of Rh@SC12H25/CFC-x, Rh(I)-SC12H25/CFC, and pristine CFC. (d) FT-IR spectra of Rh@SC12H25/CFC-x, Rh(I)-SC12H25/CFC, Rh(I)-SC12H25, and pristine CFC. (e) Raman spectra of Rh@SC12H25/CFC-x, Rh(I)-SC12H25/CFC, and Rh(I)-SC12H25. Blue and red spheres correspond to rhodium and sulfur, respectively. The black polyline in Fig. 1 was the carbon chain of dodecanethiolFigure 2 (a) SEM, (b) TEM, (c) HRTEM images (the inset in (c) showing the SAED patterns), and (d)–(g) STEM images and corresponding EDS elemental mapping images of Rh@SC12H25/CFC-0.5. (h) High-resolution S 2p XPS spectra and (i) high-resolution Rh 3d XPS spectra of Rh@SC12H25/CFC-x, Rh(I)-SC12H25/CFC, Rh2S3 /CFC and Rh/CFC.Figure 3 (a) All NRR experiments were conducted in 0.1 M Na2SO4 (pH = 2.0). (a) LSV curves, (b) RNH3 and (c) corresponding FEs at different applied potentials of Rh(I)-SC12H25/CFC, Rh@SC12H25/CFC-0.5, and Rh@SC12H25/CFC-1.0. (d) Durability and corresponding RNH3 and FE for 10 successive cycles. (e) 1H NMR spectra. (f) Electrochemical surface areas for the investigated electrocatalysts. The schematic diagram of transfer of protons and N2 molecules to the surface of (g) Rh(I)- SC12H25/CFC and (h) Rh@SC12H25/CFC-0.5, and insets in (g) and (h) of corresponding water contact angle photograph. DDT represents dodecanethiol. Figure 4  Free energy diagrams of NRR on (a) Rh(111) and (b) Rh(111)@SC12H25. (c) The calculated free-energy diagram of HER and (d) energy barriers for N2 at different coverages. (e) Structures of Rh(111)@SC12H25 with different H* coverages. Yellow, pink, blue, and green spheres correspond to sulfur, hydrogen, nitrogen, and rhodium, respectively.