Tuning Composition and Activity of Cobalt Titanium Oxide Catalysts for the Oxygen Evolution Reaction. (1st March 2016)

• Record Type: Journal Article
• Authors: Seitz, Linsey C.; Nordlund, Dennis; Gallo, Alessandro; Jaramillo, Thomas F.
• Is Part Of: Electrochimica acta. Volume 193(2016)
• Page Start: 240
• Page End: 245
• Publication Date: 2016-03-01
• Subjects: Electrocatalysis -- Water oxidation -- X-ray absorption spectroscopy; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2016.01.200
• Languages: English
• ISSNs: 0013-4686

Abstract

Graphical abstract: Abstract: Understanding catalyst function to improve activity for the oxygen evolution reaction (OER) is key to increasing the overall efficiency of electrochemical water splitting, a promising method for sustainable and clean production of hydrogen. Using a straightforward and scalable sol–gel synthesis, we explore the effects of metal composition in Cox Ti1−x Oy on electrochemical activity, atomic structure, and electronic state. Physical and electronic characterization reveal that increased amounts of Ti stabilize the 2+ oxidation state of the Co precursor and lead to formation of less active CoO-like catalysts. Conversely, films with Co:Ti ratios of 1:1 or greater result in catalysts with high activity, correlating with greater Co 3+ character, as measured by ex situ XAS for samples as-prepared and after exposure to OER conditions. Additionally, decreasing the Ti content systematically shifts the Co redox potential from approximately 1.5 V vs. RHE with a 1:3 Co:Ti ratio to 1.0 V vs. RHE with no Ti, further evidence that Ti stabilizes Co in a lower oxidation state. Controlling the oxidation state of metals in metal-oxide OER catalysts can have a profound effect on catalytic activity.