Nanoscale Limitations in Metal Oxide Electrocatalysts for Oxygen Evolution

Journal Article · Thu Sep 18 00:00:00 EDT 2014 · Nano Letters

DOI:https://doi.org/10.1021/nl502775u· OSTI ID:1233977

Viswanathan, Venkatasubramanian ^[1]; Pickrahn, Katie L. ^[2]; Luntz, Alan C. ^[3]; Bent, Stacey F. ^[2]; Nørskov, Jens K. ^[4]

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1. Department of Chemical Engineering, Stanford University, Stanford, California 94305-5025, United States, SUNCAT, SLAC National Accelerator Laboratory, Menlo Park, California 94025-7015, United States, Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
2. Department of Chemical Engineering, Stanford University, Stanford, California 94305-5025, United States
3. SUNCAT, SLAC National Accelerator Laboratory, Menlo Park, California 94025-7015, United States
4. Department of Chemical Engineering, Stanford University, Stanford, California 94305-5025, United States, SUNCAT, SLAC National Accelerator Laboratory, Menlo Park, California 94025-7015, United States

Metal oxides are attractive candidates for low cost, earth-abundant electrocatalysts. However, owing to their insulating nature, their widespread application has been limited. Nanostructuring allows the use of insulating materials by enabling tunneling as a possible charge transport mechanism. We demonstrate this using TiO₂ as a model system identifying a critical thickness, based on theoretical analysis, of about ~4 nm for tunneling at a current density of ~1 mA/cm². This is corroborated by electrochemical measurements on conformal thin films synthesized using atomic layer deposition (ALD) identifying a similar critical thickness. We generalize the theoretical analysis deriving a relation between the critical thickness and the location of valence band maximum relative to the limiting potential of the electrochemical surface process. The critical thickness sets the optimum size of the nanoparticle oxide electrocatalyst and this provides an important nanostructuring requirement for metal oxide electrocatalyst design.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Center on Nanostructuring for Efficient Energy Conversion (CNEEC)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0001060
• OSTI ID: 1233977
• Alternate ID(s): OSTI ID: 1168333
• Journal Information: Nano Letters, Journal Name: Nano Letters Vol. 14 Journal Issue: 10; ISSN 1530-6984
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
catalysis (heterogeneous)
solar (fuels)
photosynthesis (natural and artificial)
bio-inspired
electrodes - solar
defects
charge transport
materials and chemistry by design
synthesis (novel materials)
nanostructuring
atomic layer deposition
water splitting