In situ facile fabrication of Ni(OH)2 nanosheet arrays for electrocatalytic co-production of formate and hydrogen from methanol in alkaline solution

Ni(OH)2 nanosheet arrays are in situ prepared on Ni foam through very straightforward ultrasonication in HCl solution and the following rinsing and drying procedures. Value-added formate and hydrogen could be co-produced by selective oxidation of methanol without carbon dioxide emissions and water reduction over Ni(OH)2 nanosheet arrays bifunctional electrocatalysts. Energy depletion for hydrogen evolution from water could be reduced by integrating with selective methanol oxidation rather than oxygen evolution. The prepared Ni(OH)2 nanosheet arrays exhibits high activity for selective methanol oxidation in alkaline methanol-water solution. It gives a low potential of only 1.36 V (vs. reversible hydrogen electrode) to drive the current density of 100 mA cm−2. The faradaic efficiencies of formate are approximately 100% with the current densities from 10 mA cm−2 to 100 mA cm−2. Moreover, it is easy to separate the anodic and cathodic products without help of any membrane, which greatly simplifies the electrolysis system.