Strain Induced Electronic Structure Modulation on MnO2 Nanosheet by Ir Incorporation for Efficient Water Oxidation in Acid.

Abstract

Oxygen electrochemistry plays a key role in renewable energy technologies such as fuel cells and electrolyzers, but its slow kinetics limits the performance and the commercialization of such devices. Here, a strained MnO2 nanosheet induced by Ir incorporation was developed with optimized electronic structure by a simple hydrothermal method. With the incorporation of Ir, the strain induces elongated Mn-O bond length, and thereby tuning the electronic structure to favor the oxygen evolution reaction (OER) performance. The obtained catalyst exhibits an excellent mass activity of 5681 A g-1 at an overpotential of 300mV in 0.5M H2 SO4 , and reaches 50 and 100mA cm-2 at overpotentials of only 240 and 277mV, respectively. The catalyst is also stable even at 300mA cm-2 in 0.5M H2 SO4 . Using the nanosheet as the OER catalyst and the Pt/C as the hydrogen evolution reaction catalyst, a two-electrode electrolyzer achieves 10mA cm-2 with only a cell voltage of 1.453V for overall water splitting in 0.5M H2 SO4 . This strategy enables the material with high feasibility for practical applications on hydrogen production. This article is protected by copyright. All rights reserved.