Studies on the electrochemical oxidation of methanol using La2MO4 (M = Ni, Cu and Zn) catalysts

Abstract

Catalytic electrochemical oxidation of methanol is emerging as a promising alternative for clean energy production. Hence, the present investigation explores the methanol oxidation reaction (MOR) using three rare-earth metal-based oxide catalysts, La₂NiO₄ (LNO), La₂CuO₄ (LCO), and La₂ZnO₄ (LZO)—synthesized via a sustainable sol–gel method. Detailed characterization through various spectroscopic techniques confirms the successful synthesis of the catalysts with distinct crystalline phases and uniform microstructures. Electrochemical analysis reveals that the LCO exhibits superior MOR activity, compared to LNO and LZO catalysts, which is further supported by density functional theory (DFT) calculations. LCO exhibits a lower Tafel slope (42 mV dec⁻¹) than LNO (220 mV dec⁻¹) and LZO (233 mV dec⁻¹). The most favourable pathway of oxidation of methanol using the LCO catalyst primarily involves C–H bond dissociation. The anti-poisoning effect of the LCO catalyst, confirmed by CO stripping analysis, ¹³C NMR, ¹H NMR, and FTIR spectroscopy, demonstrates its strong resistance to CO poisoning and high catalytic efficiency, highlighting its potential as a promising catalyst for renewable energy applications.