Model epitaxial heterostructures for water electrolysis
EMSL Project ID
50574
Abstract
This proposal focuses on the design, fabrication and evaluation of structurally and compositionally well-defined complex oxide heterostructures that can facilitate the harvesting of visible sunlight, primarily for electron-hole pair creation and photoelectrochemical water splitting. This work will significantly deepen our understanding of light-driven water electrolysis, as well as allow us to test new concepts aimed at developing critically important materials for H2 production from aqueous solutions. The fundamental science we propose is highly relevant to the maturation of renewable energy technologies that take advantage of the abundant power of the Sun, while also addressing several key issues that stand in the way of effective implementation. The resulting materials may also be of use for photoelectrochemical CO2 reduction and organics destruction, two important processes in energy and environmental sciences.We propose to synthesize oxide/oxide and oxide/Group IV semiconductor heterojunctions to create electronic structures that will: (1) facilitate photogenerated e--h+ pair separation, thus maximizing carrier lifetimes, and, (2) efficiently couple carriers to hydrogen and oxygen evolution reactions (HER & OER) that occur on electrode surfaces in aqueous solutions. Our approach differs from that of other groups which focus on single-phase materials. The classes of heterojunctions we plan to investigate include LaxSr1-xZryTi1-yO3 on p-Ge(001), p-SrxLa1-xFeO3 on n-SrTiO3(001) and n-Fe2CrO4/p-FeTi2O4 on MgAl2O4(001). Functional properties measurements include photoconductivity, photoelectrochemistry, and mechanistic investigations of the interaction of these surfaces with aqueous solutions via ambient pressure x-ray photoelectron spectroscopy. First-principles modeling will be used throughout to aid in data interpretation, provide mechanistic details unavailable from experiment, and guide future materials selection. We seek to answer three questions consistent with our central hypothesis: (1) How can the potential energy diagrams of the heterojunction best be tuned through atomic level control to maximize e--h+ life times and carrier mobilities? (2) Can the kinetics of the redox processes be accelerated via energy-level tuning to the point that a noble metal catalyst is not needed? (3) How do the molecular-level interactions of water with the electrode surfaces influence PEC activity?
We will use the unique and powerful oxide epitaxial film growth capabilities we have developed in EMSL specifically for energy and environmental science to prepare model oxide-based heterostructures of the kinds listed above. We will also use relevant materials characterization and functional properties measurement tools in EMSL to elucidate defensible structure-property relationships, and the Cascade computer system to carry out first-principles modeling calculations. This combination of tools is required in order to move beyond the phenomenological approach which characterizes much of the literature on this topic and extract the understanding required to move this field forward at a deeper scientific level.
Project Details
Start Date
2018-10-08
End Date
2019-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Chang L., L. Wang, L. You, Z. Yang, A. Abdelsamie, Q. Zhang, and Y. Zhou, et al. 2019. "Tuning Photovoltaic Performance of Perovskite Nickelates Heterostructures by Changing the A-Site Rare-Earth Element." ACS Applied Materials & Interfaces 11, no. 17:16191-16197. PNNL-SA-140637. doi:10.1021/acsami.9b01851
Du Y., P. Sushko, S.R. Spurgeon, M.E. Bowden, J. Ablett, T. Lee, and N. Quackenbush, et al. 2018. "Layer resolved band bending at the n-SrTiO3(001)/p-Ge(001) interface." Physical Review Materials 2. PNNL-SA-134900. doi:10.1103/PhysRevMaterials.2.094602
Kaspar T.C., P.V. Sushko, S.R. Spurgeon, M.E. Bowden, D.J. Keavney, R.B. Comes, and S. Saremi, et al. 2019. "Electronic structure and band alignment of LaMnO3 / SrTiO3 polar / non-polar heterojunctions." Advanced Materials Interfaces 6, no. 1:1801428. PNNL-SA-137669. doi:10.1002/admi.201801428
Lim Z., N. Quackenbush, A. Penn, M. Chrysler, M.E. Bowden, Z. Zhu, and J. Ablett, et al. 2019. "Charge Transfer and Built-in Electric Fields Between a Crystalline Oxide and Silicon." Physical Review Letters 123, no. 2:Article Number 026805. PNNL-SA-144010. doi:10.1103/PhysRevLett.123.026805
Lin S., C. Kuo, R.B. Comes, J. Rault, J. Rueff, S. Nemsak, and A. Taleb, et al. 2018. "Interface properties and built-in potential profile of a LaCrO3/SrTiO3 superlattice determined by standing-wave excited photoemission spectroscopy." Physical Review B 98, no. 16:165124. PNNL-SA-131974. doi:10.1103/PhysRevB.98.165124
Scafetta M., Z. Yang, S.R. Spurgeon, M.E. Bowden, T.C. Kaspar, S.M. Heald, and S.A. Chambers. 2019. "Epitaxial growth and atomic arrangement in Fe2CrO4 on crystal symmetry matched (001) MgAl2O4." Journal of Vacuum Science and Technology A--Vacuum, Surfaces and Films 37, no. 3:Article number 031511. PNNL-SA-141354. doi:10.1116/1.5093537
Stoerzinger K.A., Y. Du, K. Ihm, K.L. Zhang, J. Cai, J. Diulus, and R.T. Frederick, et al. 2018. "Impact of Sr-Incorporation on Cr Oxidation and Water Dissociation in La(1-x)SrxCrO3." Advanced Materials Interfaces 5, no. 6:1701363. PNNL-SA-129951. doi:10.1002/admi.201701363
Stoerzinger K.A., Y. Du, S.R. Spurgeon, L. Wang, D.M. Kepaptsoglou, Q.M. Ramasse, and E.J. Crumlin, et al. 2018. "Chemical and Electronic Structure Analysis of a SrTiO3 (001) / p-Ge (001) Hydrogen Evolution Photocathode." MRS Communications 8, no. 2:446-452. PNNL-SA-131770. doi:10.1557/mrc.2018.38
Wang L., K.A. Stoerzinger, L. Chang, J. Zhao, Y. Li, C. Tang, and X. Yin, et al. 2018. "Tuning Bifunctional Oxygen Electrocatalysts by Changing A-site Rare-Earth Element in Perovskite Nickelates." Advanced Functional Materials 28, no. 39:1803712. PNNL-SA-135288. doi:10.1002/adfm.201803712
Wang L., K.A. Stoerzinger, L. Chang, X. Yin, Y. Li, C. Tang, and E. Jia, et al. 2019. "Strain Effect on Oxygen Evolution Reaction Activity of Epitaxial NdNiO3 Thin Films." ACS Applied Materials & Interfaces 11, no. 13:12941-12947. PNNL-SA-139978. doi:10.1021/acsami.8b21301
Wang L., Y. Du, P.V. Sushko, M.E. Bowden, K.A. Stoerzinger, S.M. Heald, and M. Scafetta, et al. 2019. "Hole-Induced Electronic and Optical Transitions in La1-xSrxFeO3 Epitaxial Thin Films." Physical Review Materials 3, no. 2:Article Number 025401. PNNL-SA-139953. doi:10.1103/PhysRevMaterials.3.025401