Enhanced Methanol Electrooxidation and Supercapacitive Performance via Compositional Engineering of Colloidal Ni-Co...

Among renewable energy technologies, particular attention is paid to electrochemically transforming methanol into valuable formate and storing energy into supercapacitors. In this study, we detailed a simple colloidal-based protocol for synthesizing a series of alloy nanoparticles with tuned Ni/Co atomic ratios, thereby optimizing their electrochemical performance. With the addition of 1 M methanol in 1 M KOH, the optimized composition was able to electrochemically produce formate at 0.149 mmol cm^-2 h^-1 with a Faradaic efficiency up to 95.1 % at 0.6 V versus Hg/HgO within a 22 h testing period. In 1 M KOH solution without methanol, the supercapacitive performance was achieved at a specific capacitance of over 1500 F g^-1, and outstanding cycling stability with only approximately 20 % decay after continuous 10000 charging-discharging cycles. These results underscore that the prepared Ni-Co alloy nanoparticles serve as multi-functional electrodes for electrochemical energy conversion and storage, particularly in the MOR and supercapacitors applications.