Journal
CHEMICAL ENGINEERING JOURNAL
Volume 405, Issue -, Pages -Publisher
ELSEVIER SCIENCE SA
DOI: 10.1016/j.cej.2020.126580
Keywords
Hierarchical nanosheets; Metal oxides; Metal phosphides; Oxygen evolution reaction; Electrocatalysis; Energy conversion
Categories
Funding
- King Saud University, Riyadh, Saudi Arabia [RSP-2020/1]
- ARC [FL160100089]
- QUT [323000-0355/51, 323000-0348/07]
Ask authors/readers for more resources
In this study, hierarchical manganese-cobalt phosphide yolk-shell spheres were successfully fabricated using self-templated method, exhibiting higher catalytic activity for oxygen evolution reaction compared to manganese-cobalt oxide yolk-shell spheres and hierarchical cobalt phosphide spheres. The high activity of the hierarchical Mn-Co phosphide yolk-shell catalyst is attributed to the existence of Mn4+/Mn3+ and Co2+/Co3+ redox couples and the formation of active metal oxyhydroxide species on its surface.
Hierarchical nanostructures with hollow architectures can provide rich active sites, improved transport of ions, and highly robust structure for electrochemical applications. In this work, we report the self-templated fabrication of hierarchical manganese-cobalt phosphide (Mn-Co phosphide) yolk-shell spheres using highly uniform cobalt glycerate spheres as sacrificial templates. Through a simple exchange reaction with the manganese precursor solution at room temperature, these cobalt glycerate spheres are readily converted to hierarchical MnCo LDH yolk-shell spheres, which can be further phosphidized at 350 degrees C under inert atmosphere to generate hierarchical Mn-Co phosphide with distinct yolk-shell morphology. When tested as an electrocatalyst for oxygen evolution reaction (OER), the hierarchical Mn-Co phosphide yolk-shell spheres exhibit an overpotential of 330 mV at a current density of 10 mA cm(-2) and a Tafel slope of 59.0 mV dec(-1), which are higher than those of Mn-Co oxide yolk-shell spheres (480 mV and 113 mV dec(-1)) and hierarchical cobalt phosphide spheres (410 mV and 61.3 mV dec(-1)). Post-OER analysis by XPS reveals that the high activity of the hierarchical Mn-Co phosphide yolk-shell catalyst originates from the existence of Mn4+/Mn3+ and Co2+/Co3+ redox couples and the formation of active metal oxyhydroxide species on its surface. The proposed self-sacrificial templating strategy will provide useful guidance for future construction of hollow inorganic metal nanostructures with yolk-shell morphology for energy storage and conversion applications.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available