Ultrafast Growth of a Cu(OH)(2)-CuO Nanoneedle Array on Cu Foil for Methanol Oxidation Electrocatalysis

摘要

A swift potentiostatic anodization method for growing a 5-7 mu m tall nanoneedle array of Cu(OH)(2)-CuO on Cu foil within 100 s has been developed. This catalytic electrode when screened for methanol oxidation electrocatalysis in 1 M KOH with 0.5 M methanol, delivered a current density as high as 70 +/- 10 mA cm(-2) at 0.65 V versus Hg/HgO which is superior to the performance of many related catalysts reported earlier. The observed activity enhancement is attributed to the formation of both Cu(OH)(2)-CuO nanoneedle arrays of high active surface area over the metallic Cu foil. In addition, the Cu(OH)(2)-CuO/Cu electrode had also exhibited excellent stability upon prolonged potentiostatic electrocatalytic oxidation of methanol while retaining the charge-transfer characteristics. Growth of such highly ordered assembly of Cu(OH)(2)-CuO nanoneedles within a minute has never been achieved before. When compared to its oxygen evolution reaction activity, the addition of 0.5 M methanol has lowered the overpotential at 10 mA cm(-2) by 334 mV, which is significant. This encourages the use of methanol as a sacrificial anolyte for energy-saving production of H-2 from water electrolysis.