Todd Schaef has been a staff member at PNNL for over 27 years and has attained the position of senior research scientist (IV). He is a team lead in the Geochemistry Group, subaccount manager for the Carbon Management and Fossil Energy sector's subsurface portfolio, and he has served as principal investigator, co-principal investigator, and project manager on a diverse range of projects funded by the U.S. Department of Energy’s (DOE) Office of Fossil Energy, Office of Energy Efficiency and Renewable Energy, and Solar Energy Technologies Office.
In these roles, Schaef leads proposals, manages project budgets, tracks milestones, prepares quarterly reports, presents findings to clients, and leads publications in high impact journals. Highlights of his recent work include efforts directed at greenhouse gas emission management and range from a field validation project to establishing research in water-bearing supercritical carbon dioxide (CO2) fluids related to energy extraction technologies. He and researcher Pete McGrail have pioneered work at PNNL on geological storage of CO2, publishing a substantial body of work investigating conversion to stable carbonate minerals. Those ideas were put to practical test in 2013 by completing the world’s first supercritical CO2 injection into a basalt formation, located in southeastern Washington State; the feat was featured on the cover of Environmental Science and Technology Letters. Schaef also has conducted laboratory and field research on marine gas hydrates and ice-like methane-bearing solid clathrate, which included teaming with University of Alaska and British Petroleum. He has developed collaborations with the University of Michigan, St. Mary’s College, and University of Washington at St. Louis, while mentoring students and faculty through the DOE-sponsored Science Undergraduate Laboratory Internship and Visiting Faculty Programs.
As part of business development at PNNL, Schaef provides leadership for project reviews, supporting institutional-level proposals spanning multiple directorates. He has received one patent for a downhole fluid injection system and has over 150 publications and presentations at national and international conferences, amassing >4,300 citations.
- BS in Geology, Texas Tech University, 1985
- MS in Geology, Texas Tech University, 1992
Awards and Recognitions
- “Best Reviewers from 2007-2011” by International Journal of Greenhouse Gas Control
- Best Paper Award, Green House Gas Technologies Conference (2008)
- Frank Kottlowski Memorial Award for “Best Paper,” American Association of Petroleum Geologists Annual Meeting (2004)
- Schaef HT, and BP McGrail. 2015. “Down-hole Fluid Injection Systems, CO2 Sequestration Methods, and Hydrocarbon MaterialRecovery Methods.” U.S. Patent No. 9,091,156.
- Miller, QRS, HT Schaef, SK Nune, KW Jung, JA Burghardt, PF Martin, MS Prowant, KM Denslow, CE Strickland, M Prasad, M Pohl, P Jaysaval, BP McGrail. 2019. Geophysical Monitoring with Seismic Metamaterial Contrast Agents. Unconventional Resources Technology Conference (URTeC) Proceedings.
- Miller, QRS, J Kaszuba, HT Schaef, ME Bowden, BP McGrail, and KM Rosso. 2019. "Anomalously low activation energy of nanoconfined MgCO3 precipitation." Chemical Communications 55, no. 48:6835-6837.
- Bowers, GM, HT Schaef, QRS Miller, ED Walter, SD Burton, DW Hoyt, and JA Horner, et al. 2019. "C13 Nuclear Magnetic Resonance Spectroscopy of Methane and Carbon Dioxide in a Natural Shale." ACS Earth and Space Chemistry3, no. 3:324–328.
- Bowers GM, JS Loring, HT Schaef, SS Cunniff, ED Walter, SD Burton, and RK Larsen, et al. 2019. "Chemical Trapping of CO2 by Clay Minerals at Reservoir Conditions: Two Mechanisms Observed by In Situ High Pressure and Temperature Experiments." ACS Earth and Space Chemistry 3, no. 6:1034-1046.
- Han, Y, MA Sinnwell, SJ Teat, ML Sushko, ME Bowden, QRS Miller, and HT Schaef, et al. 2019. "Desulfurization Efficiency Preserved in a Heterometallic MOF: Synthesis and Thermodynamically Controlled Phase Transition." Advanced Science 6, no. 7:1802056.
- Nune, SK, D Lao, ME Bowden, HT Schaef, VS Vemuri, RK Motkuri, and BP McGrail. 2019. "Investigation of Reactive Intermediates During the Synthesis of Di-n-butylmagnesium." Inorganica Chimica Acta vol 489, pp 150-154.
- Miller, QRS, HT Schaef, J Kaszuba, G Gadikota, BP McGrail, and KM Rosso. 2019. "Quantitative Review of Olivine Carbonation Kinetics: Reactivity Trends, Mechanistic Insights, and Research Frontiers." ES&T Letters, 6, 8, pp431-442.
- Miller, QRS, DA Dixon, SD Burton, ED Walter, DW Hoyt, AS McNeill, and J Moon, et al. 2019. "Surface-Catalyzed Oxygen Exchange during Mineral Carbonation in Nanoscale Water Films." Journal of Physical Chemistry C 123, no. 20:12871-12885.
- Liu, J, HT Schaef, PF Martin, BP McGrail, and LS Fifield. 2019. "Understanding H2 Evolution from the Decomposition of Di-butyl Magnesium Isomers Using In-situ X-ray Diffraction Coupled with Mass Spectroscopy." ACS Applied Energy Materials, 2, 7, pp 5272-5278.
- Loring, JS, QRS Miller, HT Schaef, CJ Thompson. 2019. “Experimental Studies of Reactivity and Transformations of Rocks and Minerals in Water-Bearing Supercritical CO2”, in: Newell, P., Ilgen, A.G. (Eds.), Science of Carbon Storage in Deep Saline Formations: Process Coupling Across Time and Spatial Scales, Elsevier.
- Miller, QRS, SK Nune, HT Schaef, K Jung, KM Denslow, MS Prowant, and PF Martin, et al. 2018. "Microporous and Flexible Framework Acoustic Metamaterials for Sound Attenuation and Contrast Agent Applications." ACS Applied Materials & Interfaces 10, no. 51:44226-44230.
- Miller, QRS, ES Ilton, O Qafoku, DA Dixon, M Vasiliu, CJ Thompson, HT Schaef, KM Rosso, JS Loring. 2018. “Water Structure Controls Carbonic Acid Formation in Adsorbed Water Films”. The Journal of Physical Chemistry Letters, 2018, 9, 17, 4988-4994.
- Motkuri RK, VS Vemuri, D Barpaga, HT Schaef, JS Loring, PF Martin, and D Lao, et al. 2018. "An Efficient, Solvent-Free Process for Synthesizing Anhydrous MgCl2." ACS Sustainable Chemistry & Engineering 6, no. 1:1048-1054.
- Qafoku, O, ES Ilton, ME Bowden, L Kovarik, X Zhang, RK Kukkadapu, and MH Engelhard, CJ Thompson, H.T. Schaef et. al., 2018. "Synthesis of Nanometer-Sized Fayalite and Magnesium-Iron(II) Mixture Olivines." Journal of Colloid and Interface Science 515.
- Evans, KA, ZC Kennedy, BW Arey, JF Christ, HT Schaef, SK Nune, and RL Erikson. 2018. "Chemically Active, Porous 3D-Printed Thermoplastic Composites." ACS Applied Materials & Interfaces 10, no. 17:15112-15121.
- Loganathan, N, GM Bowers, AO Yazaydin, HT Schaef, JS Loring, AG Kalinichev, and RJ Kirkpatrick. 2018. "Clay Swelling in Dry Supercritical Carbon Dioxide: Effects of Interlayer Cations on the Structure, Dynamics, and Energetics of CO2 Intercalation Probed by XRD, NMR, and GCMD Simulations." Journal of Physical Chemistry C 122, no. 8:4391–4402.
- Xiong, W, R Wells, JA Horner, HT Schaef, P Skemer, and DE Giammar. 2018. "CO2 Mineral Sequestration in Naturally Porous Basalt." ES&T Letters 5, no. 3:142-147.
- Bower JK, D Barpaga, S Prodinger, R Krishna, HT Schaef, BP McGrail, and MA Derewinski, et al. 2018. "Dynamic adsorption of CO2/N2 on cation-exchanged chabazite SSZ-13: A breakthrough analysis." ACS Applied Materials & Interfaces 10, no. 17:14287-14291.
- Miller, QRS, HT Schaef, J Kaszuba, L Qiu, ME Bowden, BP McGrail, and QRS Miller. 2018. "Tunable manipulation of mineral carbonation kinetics in nanoscale water films via citrate additives." ES&T 52, no. 12:7138-7148.
- Bowers G.M., J.S. Loring, H.T. Schaef, E.D. Walter, S.D. Burton, D.W. Hoyt, and S.S. Cunniff, et al. 2018. "Interaction of Hydrocarbons with Clays under Reservoir Conditions: In Situ Infrared and Nuclear Magnetic Resonance Spectroscopy and X-ray Diffraction for Expandable Clays with Variably Wet Supercritical Methane." ACS Earth and Space Chemistry2, no. 7:640-652.
- Miller QRS, ES Ilton, O Qafoku, DA Dixon, M Vasiliu, CJ Thompson, and HT Schaef, et al. 2018. "Water Structure Controls Carbonic Acid Formation in Adsorbed Water Films." Journal of Physical Chemistry Letters 9.
- Loring, JS, DH Bacon, RD Springer, A Anderko, S Gopinath, CM Yonkfonski, CJ Thompson, BP McGrail, KM Rosso, and HT Schaef. 2017. "Water Solubility at Saturation for CO2-CH4 Mixtures at 50 °C and 90 bar." Journal of Chemical & Engineering Data, 62, (5), 1608-1614.
- McGrail, BP, HT Schaef, FA Spane, JB cliff, O. Qafoku, JA Horner, CJ Thompson, AT Owen, and CE Sullivan. 2017. “Field Validation of Supercritical CO2 Reactivity with Basalts, ES&T Letters, 4 (1): 6–10.
- Childers, MI, MC Endres, CA Burns, BJ Garcia, J Liu, TW Wietsma, and AH Bonneville, J Moore, II Leavy, L Zhong, HT Schaef, et al. 2017. "Novel Highly Dispersible, Thermally Stable Core/Shell Proppants for Geothermal Applications." Geothermics 70.
- Schaef, HT, N Loganathan, GM Bowers, RJ Kirkpatrick, AO Yazaydin, SD Burton, and DW Hoyt, et al. 2017. "Tipping Point for Expansion of Layered Aluminosilicates in Weakly Polar Solvents: Supercritical CO2." ACS Applied Materials & Interfaces.
- De, S, MI Nandasiri, HT Schaef, BP McGrail, SK Nune, J Lutkenhaus. 2017. "Water-based assembly of polymer-metal organic framework (MOF) functional coatings" Advanced Materials Interfaces 4(2): Article No. 1600905.
- Schaef, HT, SK Nune, CE Strickland, KW Jung, PF Martin, JS Loring, BP McGrail. 2016. "Injectable Contrast Agents for Enhanced Subsurface Mapping and Monitoring" Energy Procedia 114 (2017) 3764–3770.
- McGrail, BP, HT Schaef, FA Spane, JA Horner, AT Owen, JB Cliff, O Qafoku, CJ Thompson, EC Sullivan. 2017. "Wallula Basalt Pilot Demonstration Project: Post-Injection Results and Conclusions" Energy Procedia,114 (2017) 5783–5790.
- Bowers, GM, HT Schaef, JS Loring, DW Hoyt, S. D. Burton, E. D. Walter and R. J. Kirkpatrick. 2016. "Role of Cations in CO2 Adsorption, Dynamics, and Hydration in Smectite Clays under in situ Supercritical CO2 Conditions." The Journal of Physical Chemistry C, 121(1): 577-592.
- Zhang W, D Banerjee, J Liu, HT Schaef, JV Crum, CA Fernandez, RK Kukkadapu, Z Nie, SK Nune, RK Motkuri, KW Chapman, MH Engelhard, JC Hayes, KL Silvers, R Krishna, BP McGrail, J Liu, and PK Thallapally. 2016. "Redox-Active Metal-Organic Composites for Highly Selective Oxygen Separation Applications." Advanced Materials28(18):3572-3577.
- Jambovane, SR, SK Nune, RT Kelly, BP McGrail, Z Wang, MI Nandasiri, S Katipamula, CD Trader, HT Schaef. 2016. "Continuous, One-pot Synthesis and Post-Synthetic Modification of NanoMOFs Using Droplet Nanoreactors”, Scientific Reports, 6, 36657.
- Nandasiri MI, SR Jambovane, BP McGrail, HT Schaef, and SK Nune. 2016. "Adsorption, Separation, and Catalytic Properties of Densified Metal-Organic Frameworks." Coordination Chemistry Reviews 311:38-52.
- Nune SK, D Lao, DJ Heldebrant, J Liu, MJ Olszta, RK Kukkadapu, LM Gordon, MI Nandasiri, GA Whyatt, CK Clayton, DW Gotthold, MH Engelhard, HT Schaef. 2016. "Anomalous Water Expulsion from Carbon-Based Rods at High Humidity." Nature Nanotechnology 11, 791–797.
- Nandasiri, MI, SR Jambovane, BP McGrail, HT Schaef, SK Nune. 2016. "Adsorption, Separation, and Catalytic Properties of Densified Metal-Organic Frameworks" Coordination Chemistry Reviews 311():38-52.
- Nandasiri, MI, J Liu, BP McGrail, JJ Jenks, HT Schaef, V Shutthanandan, Z Nie, PF Martin, SK Nune. 2016. "Increased Thermal Conductivity in Metal-Organic Heat Carrier Nanofluids" Scientific Reports (6):27805.
- Mohamed, MH, SK Elsaidi, T Pham, KA Forrest, HT Schaef, A Hogan, L Wojtas, W Xu, B Space, MJ Zaworotko, PK Thallapally 2016. "Hybrid Ultramicroporous Materials for Selective Xe Adsorption and Separation" Angewandte Chemie International Edition, 55, 8285-8289.
- Bacon DH, CMR Yonkofski, HT Schaef, MD White, and BP McGrail. 2015. "CO2 Storage by Sorption on Organic Matter and Clay in Gas Shale." Journal of Unconventional Oil and Gas Resources 12:123-133.
- Elsaidi SK, MH Mohamed, HT Schaef, A Kumar, M Lusi, T Pham, KA Forrest, B Space, W Xu, GJ Halder, J Liu, PK Thallapally, and MJ Zaworotko. 2015. "Hydrophobic Pillared Square Grids for Selective Removal of CO2 from Simulated Flue Gas." Chemical Communications 51(85):15530-15533.
- Deria, P, DA Gómez-Gualdrón, W Bury, HT Schaef, TC Wang, PK Thallapally, AA Sarjeant, RQ Snurr, JT Hupp, and OK Farha, 2015. “Ultraporous, Water Stable, and Breathing Zirconium-Based Metal–Organic Frameworks with ftw Topology” J. Am. Chem. Soc., 137 (40), pp 13183–13190.
- Bacon, DH, CM Ruprecht, HT Schaef, MD White, BP McGrail. 2015. “CO2 Storage by Adsorption on Organic Matter and Clay in Gas Shale”, Journal of Unconventional Oil and Gas Resources, V12, pages 123-133.
- Schaef, HT, JS Loring, V-A Glezakou, QRS Miller, J Chen, A T Owen, M.-S Lee, E S Ilton, A R Felmy, BP McGrail, and CJ Thompson. 2015. "Competitive sorption of CO2 and H2O in 2:1 layer phyllosilicates." Geochimica et cosmochimica Acta, 161: 248-257.
- Qafoku, O, DA Dixon, KM Rosso, HT Schaef, ME Bowden, BW Arey and AR Felmy. 2015. "Dynamics of Magnesite Formation at Low Temperature and High pCO2 in Aqueous Solution." ES&T, 49(17): 10736-10744.
- Loring, JS, J Chen, P. Benezeth, O Qafoku, ES Ilton, NM Washton, CJ Thompson, PF Martin, BP McGrail, KM Rosso, HT Schaef. 2015. "Evidence for Carbonate Surface Complexation during Forsterite Carbonation in Wet Supercritical Carbon Dioxide." Langmuir, 31(27): 7533-7543.
- Miller, QRS, JP Kaszuba, HT Schaef, ME Bowden, BP McGrail. 2015. Impacts of Organic Ligands on Forsterite Reactivity in Supercritical CO2 Fluids. ES&T, 49 (7): 4724–4734.
- Rose, KK, JE Johnson, ME Torres, WL Hong, L Giosan, E Solomon, M Kastner, T Cawthern, PE Long, Schaef HT. 2014. "Anomalous porosity preservation and preferential accumulation of gas hydrate in the Andaman accretionary wedge, NGHP-01 site 17A" Marine and Petroleum Geology 58(A):99-116.
- Loring, JS, ES Ilton, J Chen, CJ Thompson, PF Martin, P Bénézeth, KM Rosso, AR Felmy, and HT Schaef. 2014. "In Situ Study of CO2 and H2O Partitioning between Na–Montmorillonite and Variably Wet Supercritical Carbon Dioxide."Langmuir, 30(21): 6120-6128.
- Schaef, HT, V-A Glezakou, AT Owen, S Ramprasad, PF Martin, BP McGrail. 2014. “Surface Condensation of CO2 onto Kaolinite”, ES&T Letters 1, 142-145.
- Schaef, HT, JA Horner, AT Owen, CJ Thompson, JS Loring, and BP McGrail. 2014. “Mineralization of Basalts in the CO2-H2O-SO2-O2 System”, ES&T, 48, 5298-5305.
- Schaef, HT, BP McGrail, JL Loring, ME Bowden, BW Arey, and KM Rosso. 2013. "Forsterite [Mg2SiO4)] Carbonation in Wet Supercritical CO2: An in situ High-Pressure X-ray Diffraction Study." ES&T, 174-181.
- Miller QRS, CJ Thompson, JS Loring, CF Windisch, Jr, ME Bowden, DW Hoyt, JZ Hu, BW Arey, KM Rosso, and HT Schaef. 2013. "Insights into Silicate Carbonation Processes in Water-Bearing Supercritical CO2 Fluids." International Journal of Greenhouse Gas Control, 15:104-118.
- Wang Z, AR Felmy, CJ Thompson, JS Loring, AG Joly, KM Rosso, HT Schaef, and DA Dixon. 2013. "Near-Infrared Spectroscopic Investigation of Water in Supercritical CO2 and the Effect of CaCl2." Fluid Phase Equilibria 338:155-163.
- Schaef HT, BP McGrail, AT Owen, and BW Arey. 2013. "Mineralization of Basalts in the CO2-H2O-H2S System." International Journal of Greenhouse Gas Control, 16:187-196.
- Riley, BJ, BR Johnson, HT Schaef, and SK Sundaram. 2013. "Sublimation-Condensation of Multiscale Tellurium Structures." Journal of Physical Chemistry C 117(19):10128-10134.
- Loring, JS, HT Schaef, CJ Thompson, RVF Turcu, QR Miller, J Chen, JZ Hu, DW Hoyt, PF Martin, ES Ilton, AR Felmy, and KM Rosso. 2013. "Clay hydration/dehydration in dry to water-saturated supercritical CO2: Implications for caprock integrity." in Energy Procedia, vol 37, 5443-5448.
- Schaef, HT, QRS Miller, CJ Thompson, JS Loring, MS Bowden, BW Arey, BP McGrail, KM Rosso. 2013. “Silicate Carbonation in Supercritical CO2 Containing Dissolved H2O: an in situ High Pressure X-Ray Diffraction and Infrared Spectroscopy Study” in Energy Procedia, Vol 37, 5892-5896.
- Rother, G, ES Ilton, D Wallacher, T Hauss, HT Schaef, O Qafoku, KM Rosso, AR Felmy, EG Krukowski, AG Stack, et al. 2013. "CO2 Adsorption to Sub-Single Hydration Layer Montmorillonite Clay Studied by Excess Sorption and Neutron Diffraction." ES&T, 47 (1) pp. 205-211.
- Glezakou, V-A., BP McGrail, and HT Schaef. 2012. "Molecular interactions of SO2 with carbonate minerals under co-sequestration conditions: A combined experimental and theoretical study." Geochimica et Cosmochimica Acta 92(0): 265-274.
- Ilton, ES, HT Schaef, O Qafoku, KM Rosso and AR Felmy. 2012. "in situ X-ray Diffraction Study of Na+ Saturated Montmorillonite Exposed to Variably Wet Super Critical CO2." ES&T 46(7): 4241-4248.
- Loring, JS, HT Schaef, RVF Turcu, CJ Thompson, QRS Miller, PF Martin, J Hu, DW Hoyt, O Qafoku, ES Ilton. 2012. "In Situ Molecular Spectroscopic Evidence for CO2 Intercalation into Montmorillonite in Supercritical Carbon Dioxide." Langmuir 28(18): 7125-7128.
- Windisch, CF, Jr, HT Schaef, PF Martin, AT Owen and BP McGrail. 2012. "Following O-18 uptake in scCO2-H2O mixtures with Raman spectroscopy." Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy 94: 186-191.
- Felmy, AR, O Qafoku, BW Arey, J Z Hu, M Hu, HT Schaef, ES Ilton, NJ Hess, CI Pearce, J Feng, et al. 2012. "Reaction of water-saturated supercritical CO2 with forsterite: Evidence for magnesite formation at low temperatures." Geochimica et Cosmochimica Acta 91: 271-282.
- Loring, JS, CJ Thompson, C Zhang, Z Wang, HT Schaef, and KM Rosso. 2012. "In Situ Infrared Spectroscopic Study of Brucite Carbonation in Dry to Water-Saturated Supercritical Carbon Dioxide." Journal of Physical Chemistry A 116(19): 4768-4777.
- Schaef, HT, CF Windisch, Jr., BP McGrail, PF Martin and KM Rosso. 2011. "Brucite Mg(OH)2 carbonation in wet supercritical CO2: An in situ high pressure X-ray diffraction study." Geochimica et Cosmochimica Acta 75(23).
- Rai D, M Yui, HT Schaef, and A Kitamura. 2011. "Thermodynamic Model for SnO2(cr) and SnO2(am) Solubility in the Aqueous Na+-H+ -OH- -Cl- -H2O System." Journal of Solution Chemistry 40:1155-1172.
- Loring JS, CJ Thompson, Z Wang, AG Joly, DS Sklarew, HT Schaef, ES Ilton, KM Rosso, and AR Felmy. 2011. "In Situ Infrared Spectroscopic Study of Forsterite Carbonation in Wet Supercritical CO2." Environmental Science & Technology 45(14):6204-6210.
- Schaef, H.T., B.P. McGrail and A.T. Owen, 2011. “Basalt Reactivity Variability with Reservoir Depth in Supercritical CO2and Aqueous Phases”, Energy Procedia, 4:4977-4984.
- White MD, BP McGrail, HT Schaef, JZ Hu, DW Hoyt, AR Felmy, KM Rosso, and SK Wurstner. 2011. "Multiphase Sequestration Geochemistry: Model for Mineral Carbonation." Energy Procedia 4:5009-5016.
- Windisch, Charles F Jr; Glezakou, Vanda; Martin, Paul (PNNL); McGrail, B Peter; Schaef, Herbert T, 2011. “Transposition of the Fermi Dyad in CO2 by Labeled Oxygens”, Journal of Physical Chemistry B, (submitted July, 2011).
- Schaef, H.T., Ilton, E.S., Qafoku, O., Martin, P.F., Felmy, A.R., and Rosso, K.M., 2011, “In situ XRD Study of Ca2+Saturated Montmorillonite (STX-1) Exposed to Anhydrous scCO2”, International Journal of Greenhouse Gas Control, submitted (submitted June, 2011).
McGrail, BP, HT Schaef, V-A Glezakou, LX Dang, and AT Owen. 2009. “Water Reactivity in the Liquid and Supercritical CO2Phase: Has Half the Story Been Neglected?” Energy Procedia 1.