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

• Published in: Chemistry : a European journal Vol. 23; no. 33; pp. 8051 - 8057
• Main Authors: Bose, Suranjana, Debgupta, Joyashish, Ramsundar, Rani M., Das, Samar K.
• Format: Journal Article
• Language: English
• Published: Germany 12.06.2017
• Subjects: alpha-CO(OH)2 film; heterogeneous electrocatalyst; Tafel plots; water oxidation; zeolite-Y support; Tafel plots; heterogeneous electrocatalyst; zeolite-Y support; water oxidation; alpha-CO(OH)2 film
• ISSN: 0947-6539; 1521-3765; 1521-3765
• DOI: 10.1002/chem.201700955

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 O2 (mol Co)−1 s−1 at 1 mA cm−2) than the existing α‐Co(OH)2‐based electrocatalysts operating in alkaline medium. Cobalt electrocatalysis: A simple but unique technique to in situ generate a thin‐film of α‐Co(OH)2 on the surface of zeolite‐Y that acts as an efficient and stable catalyst for electrochemical water oxidation at alkaline pH is reported. A Tafel slope of 59 mV decade−1 in 0.1 m KOH (pH 13) suggests faster oxygen evolution kinetics (overpotential=329 mV; turnover frequency=0.35 molO2  molCo−1 s−1 at 1 mA cm−2) than the existing α‐Co(OH)2‐based electrocatalysts operating in alkaline medium.