Epitaxial oxide/oxide and oxide/semiconductor heterostructures for water electrolysis
EMSL Project ID
49306
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: (1) p-SrxLa1-xCrO3 on n-SrTiO3(001), (2) [(AETiO3)n / (LaCrO3)n']m and LaxAE1-xCryTi1-yO3 on n-SrTiO3(001) (AE = alkaline earth metal -- Sr or Ba), (3) [(aFe2O3)n / (a-Cr2O3)n']m and a-CrxFe2-xO3 on Pt/a-Al2O3(0001), and, (4) LaxSr1-xZryTi1-yO3 on np-Ge(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
Project type
Large-Scale EMSL Research
Start Date
2016-10-01
End Date
2018-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Bagus P.S., C.J. Nelin, C.R. Brundle, and S.A. Chambers. 2019. "A New Mechanism For XPS Line Broadening: The 2p-XPS of Ti(IV)." Journal of Physical Chemistry C 123, no. 13:7705-7716. PNNL-SA-135550. doi:10.1021/acs.jpcc.8b05576
Chambers S.A., M.H. Engelhard, L. Wang, T.C. Droubay, M.E. Bowden, M.J. Wahila, and N. Quackenbush, et al. 2017. "X-ray photoelectron spectra for single-crystal Ti2O3: experiment and theory." Physical Review. B, Condensed Matter and Materials Physics 96, no. 20:205143. PNNL-SA-127619. doi:10.1103/PhysRevB.96.205143
Chambers SA, TC Droubay, TC Kaspar, IH Nayyar, ME McBriarty, SM Heald, DJ Keavney, ME Bowden, and P Sushko. 2017. "Electronic and Optical Properties of a Semiconducting Spinel (Fe2CrO4)." Advanced Functional Materials 27(9):Article No. 1605040. doi:10.1002/adfm.201605040
Chambers SA, Y Du, RB Comes, SR Spurgeon, and P Sushko. 2017. "The effects of core-level broadening in determining band alignment at the epitaxial SrTiO3(001)/p-Ge(001) heterojunction." Applied Physics Letters 110(8):082104. doi:10.1063/1.4977422
Chambers S.A., Y. Du, Z. Zhu, J. Wang, M.J. Wahila, L.J. Piper, and A. Prakash, et al. 2018. "Interconversion of intrinsic defects in SrTiO3(001)." Physical Review B 97, no. 24:245204. PNNL-SA-131613. doi:10.1103/PhysRevB.97.245204
Comes RB, and SA Chambers. 2016. "Interface Structure, Band Alignment, and Built-In Potentials at LaFeO3/n-SrTiO3 Heterojunctions." Physical Review Letters 117(22):Article No. 226802. doi:10.1103/PhysRevLett.117.226802
Comes RB, SR Spurgeon, DM Kepaptsoglou, MH Engelhard, DE Perea, TC Kaspar, QM Ramasse, P Sushko, and SA Chambers. 2017. "Probing the Origin of Interfacial Carriers in SrTiO3-LaCrO3 Superlattices." Chemistry of Materials 29(3):1147-1155. doi:10.1021/acs.chemmater.6b04329
Debehets J, P Homm, M Menghini, SA Chambers, C Marchiori, M Heyns, JP Locquet, and JW Seo. 2018. "Detecting Fermi-level shifts by Auger electron spectroscopy in Si and GaAs." Applied Surface Science 440:386-395. doi:10.1016/j.apsusc.2018.01.079
doi:10.1017/S1431927617000368
Measurement Error in Atomic-Scale Scanning Transmission Electron Microscopy—
Energy-Dispersive X-Ray Spectroscopy (STEM-EDS) Mapping of a Model Oxide Interface
Du Y, C Li, KHL Zhang, ME McBriarty, SR Spurgeon, HS Mehta, D Wu, and SA Chambers. 2017. "An all-perovskite p-n junction based on transparent conducting p-La1-xSrxCrO3 epitaxial layers." Applied Physics Letters 111(6):063501. doi:10.1063/1.4997410
J.C. Woicik, J.M. Ablett, N.F. Quackenbush, A.K. Rumaiz, C. Weiland, T.C. Droubay, S.A. Chambers, ?Charge-transfer excitations in the photo-ionization of NiO?, Phys. Rev. B. 97, 245142 (2018).
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, K Ahmadi-Majlan, E Grimley, Y Du, ME Bowden, R Moghadam, JM LeBeau, SA Chambers, and J Ngai. 2017. "Structural and electrical properties of single crystalline SrZrO3 epitaxially grown on Ge (001)." Journal of Applied Physics 122(8):Article No. 084102. doi:10.1063/1.5000142
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
Moghadam R, ZY Xiao, K Ahmadi-Majlan, E Grimley, ME Bowden, PV Ong, SA Chambers, JM LeBeau, X Hong, P Sushko, and J Ngai. 2017. "An Ultrathin Single Crystalline Relaxor Ferroelectric Integrated on a High Mobility Semiconductor." Nano Letters 17(10):6248-6257. doi:10.1021/acs.nanolett.7b02947
Spurgeon S.R., P. Sushko, A. Devaraj, Y. Du, T.C. Droubay, and S.A. Chambers. 2018. "Onset of Phase Separation in the Double Perovskite Oxide La2MnNiO6." Physical Review B 97, no. 13:134110. PNNL-SA-123784. doi:10.1103/PhysRevB.97.134110
Spurgeon SR, P Sushko, SA Chambers, and RB Comes. 2017. "Dynamic Interface Rearrangement in LaFeO3 / n-SrTiO3 Heterojunctions." Physical Review Materials 1(6):063401. doi:10.1103/PhysRevMaterials.1.063401
Stoerzinger K.A., L. Wang, Y. Ye, M.E. Bowden, E.J. Crumlin, Y. Du, and S.A. Chambers. 2018. "Linking surface chemistry to photovoltage in Sr-substituted LaFeO3 for water oxidation." Journal of Materials Chemistry A 6, no. 44:22170–22178. PNNL-SA-135655. doi:10.1039/c8ta05741a
Stoerzinger KA, RB Comes, SR Spurgeon, S Thevuthasan, K Ihm, EJ Crumlin, and SA Chambers. 2017. "Influence of LaFeO3 surface termination on water reactivity." The Journal of Physical Chemistry Letters 8(5):1038-1043. doi:10.1021/acs.jpclett.7b00195
Stoerzinger KA, Y Du, K Ihm, KHL Zhang, J Cai, JT Diulus, RT Frederick, GS Herman, EJ Crumlin, and SA Chambers. 2018. "Impact of Sr-Incorporation on Cr Oxidation and Water Dissociation in La(1-x)SrxCrO3." Advanced Materials Interfaces 5(6):1701363. doi:10.1002/admi.201701363
Wang L., Y. Du, L. Chang, K.A. Stoerzinger, M.E. Bowden, and S.A. Chambers. 2018. "Band Alignment and Electrocatalytic Activity at the p-n La0.88Sr0.12FeO3 / SrTiO3(001) Heterojunction." Applied Physics Letters 112, no. 26:261601. PNNL-SA-135023. doi:10.1063/1.5030897
Woicik J.C., J. Ablett, N. Quackenbush, A. Rumaiz, C.R. Weiland, T.C. Droubay, and S.A. Chambers. 2018. "Experimental assignment of many-electron excitations in the photoionization of NiO." Physical Review. B, Condensed Matter and Materials Physics 97, no. 24:245142. PNNL-SA-131960. doi:10.1103/PhysRevB.97.245142