Electrochemical Water Oxidation Catalyzed by an In Situ Generated α‐Co(OH) 2 Film on Zeolite‐Y Surface

The design and synthesis of an efficient and robust water‐oxidation catalyst with inexpensive materials remains an important challenge in the context of artificial photosynthesis. Herein, a simple but unique technique is reported to in situ generate a thin‐film of α‐Co(OH) 2 on the surface of zeolite‐Y [hereafter referred to as Y‐α‐Co(OH) 2 ] that acts as an efficient and stable catalyst for electrochemical water oxidation in alkaline medium. Catalyst Y‐α‐Co(OH) 2 is so stable that it retains its catalytic activity even after 2000 cyclic voltammetric cycles of water oxidation. Expectedly, the chemical composition of α‐Co(OH) 2 on the surface of zeolite‐Y remains same as that of parent Y‐α‐Co(OH) 2 after 2000 electrocatalytic cycles. A Tafel slope as low as 59 mV decade −1 in 0.1  m KOH (pH 13) suggests faster oxygen evolution kinetics (overpotential=329 mV; turnover frequency=0.35 mol O 2 (mol Co) −1  s −1 at 1 mA cm −2 ) than the existing α‐Co(OH) 2 ‐based electrocatalysts operating in alkaline medium.