HMTA-assisted formation of hierarchical Co-based materials built by low-dimensional substructures as water oxidation electrocatalysts†
Abstract
Developing water oxidation catalysts with low overpotential and high stability has become the frontier of energy conversion research. Herein, we report a micro-flowers (MFs) cobalt (Co) based material with a three-dimensional (3D) open structure consisting of two-dimensional (2D) nanosheets. The MFs were synthesized by using HMTA to adjust the microscopic environment of the Co ions, which consist of Co3O4 and Co(OH)2. Electrochemical evaluation reveals that the MFs electrocatalysts exhibit a low overpotential of η = 295 mV at 10 mA cm−2 and a long-term stability in a 1.0 M KOH solution. The excellent OER performance is attributed to the hierarchical structure, which combines the fast charge transfer ability of low-dimensional structures and the fast mass transfer ability of high-dimensional structures.