Ultrafine IrNi Bimetals Encapsulated in Zeolitic Imidazolate Frameworks‐Derived Porous N‐Doped Carbon for Boosting Oxygen Evolution in Both Alkaline and Acidic Electrolytes
Xiu Chen, Mingyue Xu, Shang Li, Cuicui Li, Xuechu Sun, Shichun Mu, Jun Yu
Abstract
Abstract Developing cost‐effective and active catalysts for oxygen evolution reaction (OER) towards renewable energy‐related system, and applying the catalysts under both alkaline and acidic conditions is still a great challenge. In this work, a facile wet‐chemical method is reported to synthesize ultrafine Ir x Ni y alloy encapsulated in porous N‐doped carbon (BMNC) derived from bimetallic zeolitic imidazolate frameworks (ZIFs). Benefiting from the advantages of alloy effect between Ir and Ni, high surface area and more active site exposing, the optimal sample Ir 3 Ni 2 /BMNC with only 7.7 wt% Ir content reveals outstanding OER electrocatalytic activity in alkaline and acidic electrolyte. When evaluated in 1 m KOH, Ir 3 Ni 2 /BMNC exhibits low overpotential of 279 mV to drive current density of 10 mA cm −2 compared with IrO 2 (322 mV), 59.4 times Ir mass activity of 303 A g Ir −1 higher than IrO 2 (5.1 Ag Ir −1 ) and prominent durability of 40 000 s for chronopotentiometry test. Assessed in 0.1 m HClO 4 , Ir 3 Ni 2 /BMNC also possesses long stability of 40 000 s for chronopotentiometry, high current density (η 10 = 321 mV) and 19.9 times Ir mass activity (303 A g Ir −1 ) superior to IrO 2 of η 10 = 350 mV and 15.2 A g Ir −1 , respectively. The brilliant durability attributes to the structure of alloy nanoparticles anchored in porous N‐doped carbon.