Ultralow noble metals doping enables metal-organic framework derived Ni(OH)2nanocages as efficient water oxidation electrocatalysts

Rational design of highly efficient electrocatalysts with favorable electronic and geometric structure toward sluggish oxygen evolution reaction (OER) grasps the key in unlocking the wide application of hydrogen energy through water electrolysis. Herein, an innovative type of ultralow noble metals (Ir and Ru) doped hollow Ni(OH)2 nanocage electrocatalysts are successfully constructed through an ion-assisted etching protocol. Interestingly, a remarkable OER activity is achieved for Ir-Ni(OH)2 nanocage, delivering a current density of 10 mA cm−2 with an ultralow overpotential of 248 mV in 1 M KOH electrolyte. More importantly, this synthetic method can also be extended to the synthesis of Ru-Ni(OH)2 nanocages with outstanding OER performance. Mechanism study reveals that the superior OER performance is attributed to the ultralow noble metal doping, which not only effectively modifies the electronic structure of Ni(OH)2, but also functions as the active sites toward OER. Moreover, the highly open hollow nanocage structure enables the catalyst to provide more exposed active sites available for reaction intermediates, contributing to the outstanding OER performance.