(617gu) Transition Metal Modified Zirconium Phosphates for the Oxygen Evolution Reaction

Joel Sanchez⁺, Ieva Narkeviciute⁺, Mario Ramos⁺⁺, Jorge Colón⁺⁺, Thomas F. Jaramillo⁺

⁺Department of Chemical Engineering, Stanford University, Stanford, California, 94305

⁺⁺Department of Chemistry, University of Puerto Rico, Río Piedras, Puerto Rico 00931

A sustainable energy supply in the future will depend on innovative breakthroughs regarding the design of efficient, reliable, and inexpensive systems that allow for the conversion and storage of renewable energy sources. Water electrolysis provides a suitable method to generate hydrogen and oxygen gas with the scalable potential to store intermittent renewable energy needed to power a sustainable energy grid. Converging towards this reality, the efficiency of electrolyzers must be optimized through the development of highly active and stable catalysts in order to reduce the kinetic overpotenial losses associated with driving the oxygen evolution reaction (OER).^[1] Currently, due to acid-aggressive and strong corrosive conditions in which OER takes place, the only active and stable catalyst are precious metals (IrO₂and RuO₂) and the implementation of acid stable non-precious metal catalyst is unknown.

Recent theory has shown that confining catalyst materials within nanoscale dimensions can lead to improvements for the OER by introducing reaction channels that break scaling relations through increased selectivity. Therefore, in this study, we focus on leveraging the versatility of nanomaterials by taking advantage of the layered structure of Zirconium Phosphate (ZrP).^[2] ZrP is an acidic and inorganic cation exchange material which is stable at low pH and high temperatures with the ability to intercalate molecular species with dimensions up to 24 Å.^[3,4] In base, some of the most active and stable catalysts consist of Fe, Ni, Co, their oxides, or mixtures thereof; in this study we investigate ZrP modified with a range of transition metal oxides known to catalyze the OER.^[5] The modified ZrP materials are characterized through X-ray powder diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and then further tested for OER activity.

References:

1. 1. Burke, M. S., et al. Chemistry of Materials, 2005, 27(22), 7549â??7558.
2. 2. Doyle, A., et al. ChemCatChem, 2015, 7, 738-742.
3. 3. Santiago, M.E.B, et al. Langmuir, 2007, 23, 7810-7817.
4. 4. Santiago, M.E.B, et al. Langmuir, 2012, 28, 4447-4452.
5. 5. McCrory, C.C.L, et al. Journal of the American Chemical Society, 2015, 137, 4347-4357.