Sustaining Methanol-Oxidation and Hydrogen Evolution at Low Voltage by Applying Periodic Polarity Reversal on a Symmetric Pt-Based Electrode Pair

It has been established that Pt-based electrocatalysts can enable the methanol oxidation reaction (MOR) to produce value-added formate at ultralow potentials. However, their sustainability is severely limited due to acute CO poisoning, particularly at high current densities. To address this challenge, we develop Pt@NiM-LDH electrocatalysts (M = Co, Mn, Cu, Fe) by anchoring Pt sites onto NiM layered double hydroxide (LDH) support via Pt─O─Ni bonding, which mitigates CO poisoning. Critically, it is found that applying periodic current polarity reversal to a symmetric Pt@NiCo-LDH‖Pt@NiCo-LDH electrode pair drastically attenuates CO-poisoning. This system thereby enables concurrent productions of hydrogen and formate for at least 120 h at an industrial-level current density (300 mA cm⁻²) and a low cell voltage of 1.02 V, yielding a combined Faradaic efficiency of nearly 200%. Comprehensive experimental and theoretical studies reveal that the NiCo-LDH support electronically modulates the Pt sites, suppressing both CO formation and adsorption. Furthermore, it is verified that the polarity reversal strategy weakens CO adsorption strength by inducing structural reconstruction of the electrical double layer (EDL). These synergistic mechanisms significantly enhance the sustainability of Pt-based electrodes for coupled MOR‖HER electrolysis. This work thus provides a promising strategy for designing highly efficient and CO-tolerant Pt-based electrocatalytic systems.