Crystal facets-predominated oxygen evolution reaction activity of earth abundant CoMoO4 electrocatalyst

Abstract

The surface property of an electrocatalyst is crucial for oxygen evolution reaction (OER). In this work, we have successfully prepared CoMoO4 nanorods (NR) with {100} facets exposed mainly and CoMoO4 nanosheets (NS) with {010} exposed mainly via a facile hydrothermal route. It is found that although the CoMoO4 NS has a 7 times higher surface area (49.3 m2 g−1) than the CoMoO4 NR (7.0 m2 g−1), the CoMoO4 NR has a 5.7 times higher OER current density (8.93 mA cmcat−2) than the CoMoO4 NS (1.56 mA cmcat−2) at 550 mV. Its higher intrinsic OER activity is mainly attributed to the exposed {100} facets of CoMoO4 NR. Compared with {010} facets (0.41 Jm-2), the {100} facets with a higher surface energy (0.54 Jm-2) are more reactive, and the more Co atoms on (100) surface can provide more OER active sites. This work demonstrates that the control of active facets exposed is a promising way for the development of efficient OER catalysts.