Gary L. Haller

Research Professor of Chemical & Environmental Engineering
Room / Office: Mason 305
Office Address:
9 Hillhouse Avenue
New Haven, CT 06511
Mailing Address:
P.O. Box 208286
New Haven, CT 06520
Phone: (203) 432-4378
Fax: (203) 432-4387

Ph.D., Northwestern University


The goal of our research has been to understand and rationalize heterogeneous catalytic activity and selectivity in terms of surface or catalytic site structure. Surface and/or site structure primarily requires spectroscopic characterization, but this is usually accompanied by physi- and chemisorption and model catalytic activity studies. We are currently investigating a variety of catalysts based on structured carbon supports, specifically on single- and multi-walled carbon nanotubes (SWCNT and MWCNT).

Carbon supports, e.g., MWCNT, have a particularly desirable property of stability, relative to oxides, in hot liquid water, the medium for most biomass refining and processing. Grafted nanoparticles of oxides on MWCNT, e.g., ZrO2/MWCNT, can also be hydrothermally stable for ZrO2 particles of a few nm isolated on the hydrophobic MWCNT support. Acid sites can be created by sulfated or tungstated ZrO2 and co-supported metals, e.g., Ni, provide bi-functional sites for hydrolysis (acid function) and hydrogenation (metal function) required for biomass processing in liquid water at temperatures in the range of 200°C.

Integrated, multi-catalysts processes for methanol-to-gasoline (MTG) and methanol-to-olefins (MTO) are studied in connection with consulting and a visiting professorship at the Technical University of Munich.

Selected Publications:

  • C. Liu, T. Bolin, P. Northrup, S. Lee, C. McEnally, P. Kelleher, L. Pfefferle, G. L. Haller. Combined Zr and S XANES analysis on S-ZrO2/MWCNT solid acid catalyst. Topics in Catalysis 2014, 57(6-9), 693-705.

  • C. Liu, L. D. Pfefferle, G. L. Haller. The electronic structure or charge delocalization of sulfated zirconia (supported on multi-walled carbon nanotubes): Acid sites probed by X-ray absorption spectroscopy. Topics in Catalysis 2014, 57(6-9), 774-784.

  • X. Sun, S. Mueller, Y. Liu, H. Shi, G. L. Haller, M. Sanchez-Sanchez, A. C. van Veen, J. A. Lercher. On reaction pathways in the conversion of methanol to hydrocarbons on HZSM-5. J. Catal. 2014, 317, 185-197.

  • Z. Zhang, L. Pfefferle, G. L. Haller. Characterization of functional groups on oxidized multi-wall carbon nanotubes by potentiometric titration. Catal. Today 2015, 249, 23-29.

  • S. Mueller, Y. Liu, M. Vishnuvarthan, X. Sun, A. C. van Veen, G. L. Haller, M. Sanchez-Sanchez, J. A. Lercher. Coke formation and deactivation pathways on H-ZSM-5 in the conversion of methanol to olefins J. Catal. 2015, 325, 48-59.

Selected Patents:

  • "Growth of Nanostructures with Controlled Diameter," US patent 7,485,279 B2, Feb. 3, 2009.
  • "Controlled Growth of Single-wall Carbon Nanotubes," US patent 7,357,983 B2, Apr. 15, 2008.

Additional Appointments:

  • Visiting Fellow, Institute for Advanced Study, Technical University of Munich
  • Director, Henry Koerner Center for Emeritus Faculty, Yale University