New Insight into N,S-Doped Carbon Nanosheets Embedded with Ni/NiO Nanocluster Electrocatalysts Derived from Conjugated Polymers for the Oxidation of 2-Propanol to Acetone

Propanol electrooxidation represents a vital reaction, as it offers a pathway for directly transforming renewable resources into valuable chemical products and green hydrogen. This study presents an approach for the synthesis and characterization of Ni/NiO-NS@CN nanosheets using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), chronoamperometry (i-t), field emission scanning electron microscopy (FE-SEM), high-resolution transmission microscopy (HR-TEM), UV-vis spectroscopy, Fourier transform infrared (FTIR), X-ray photoelectron (XP) and Raman spectroscopy, X-ray diffraction (XRD), energy-dispersive analysis of X-ray (EDAX), BET (Braunner-Emmet-Teller) surface area measurements, and thermogravimetric analysis (TGA) were employed to provide in-depth characterization of the nanocomposite. The analysis revealed a unique nanosheet template decorated with Ni/NiO, C, N, O, and S elemental composition, exhibiting an irregular distribution with a face-centered cubic (FCC) crystal structure and interlayer d-spacing of similar to 0.23 nm. Moreover, the defect-induced carbon backbone featured Ni in the +2 oxidation state. Remarkably, the Ni/NiO-NS@CN nanocomposite demonstrated exceptional electrocatalytic activity and stability for 15,000 s at 0.45 V vs SCE (saturated calomel electrode) in the electrooxidation of isopropanol (iPrOH). It exhibited a significantly lower onset potential (0.32 V vs SCE) and superior performance as compared to oxygen evolution reaction (OER), as well as electrooxidation reactions of ethanol and methanol. Furthermore, this study employed C-13 NMR spectroscopy to identify acetone as the primary product of the iPrOH oxidation reaction (iPrOR). Impressively, after 10 h of reaction time, high selectivity and 73% Faradaic efficiency were achieved. This research underscores the critical role of catalyst structure and applied potential in influencing the electrooxidation of iPrOH providing valuable insights under various conditions and opening promising avenues for future green energy and chemical synthesis developments.