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

5 years ago

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

Joyashish Debgupta, Rani M. Ramsundar, Samar K. Das, Suranjana Bose

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.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201700955