Christopher Hahn

Associate Staff Scientist

Phone: 
650-926-8521

Global dependence on fossil fuels as energy sources and the alarming increase of greenhouse gas emissions has necessitated the development of carbon-free and carbon-neutral renewable energy sources for the future. The sequestration of CO2 emissions and the subsequent electrochemical reduction of CO2 into fuel products, forms a carbon-neutral synthetic fuel cycle which could potentially be streamlined into existing fuel infrastructures. To date, only Cu has displayed any propensity as a catalyst to electrochemically reduce CO2 into longer chain hydrocarbons, carboxylates, and alcohols. However, Cu generally requires a large overpotential to reduce CO2 and has little product selectivity as a catalyst. Recent theoretical work by SUNCAT indicates that scaling relations associated with reaction adsorbate binding energies could be limiting the CO2 reduction activity of transition metal catalysts. These studies suggest that alloying can improve the activity and selectivity of a CO2 reduction catalyst by decoupling the binding energies of specific reaction intermediates. In collaboration with theorists at SUNCAT, I use physical vapor deposition to synthesize a theory targeted library of alloy catalysts to screen for CO2 electroreduction activity, selectivity, and stability.

Publications

Electrochemical CO2 Reduction over Compressively Strained CuAg Surface Alloys with Enhanced Multi-Carbon Oxygenate Selectivity. Ezra L. Clark, Christopher Hahn, Thomas F. Jaramillo, Alexis T. Bell . Journal of the American Chemical Society . 2017. Machine-Learning Methods Enable Exhaustive Searches for Active Bimetallic Facets and Reveal Active Site Motifs for CO2 Reduction. Zachary Ulissi, Michael Tang, Jianping Xiao, Xinyan Liu, Daniel A Torelli, Mohammadreza Karamad, Kyle Cummins, Christopher Hahn, Nathan S Lewis, Thomas F Jaramillo, Karen Chan, Jens K Norskov . ACS Catalysis , 7 , 6600- . 2017.
Promoter effects of alkali metal cations on the electrochemical reduction of carbon dioxide. Joaquin Resasco, Leanne D. Chen, Ezra Clark, Charlie Tsai, Christopher Hahn, Thomas Jaramillo, Karen Chan, Alexis Bell . Journal of the American Chemical Society , 139 , 11277- 11287 . 2017. Understanding the Influence of [EMIM] Cl on the Suppression of the Hydrogen Evolution Reaction on Transition Metal Electrodes. Jeremy Feaster, Anna Jongerius, Xinyan Liu, Makoto Urushihara, Stephanie A. Nitopi, Christopher Hahn, Karen Chan, Jens K. Nørskov, Thomas F. Jaramillo . Langmuir . 2017.
Understanding Selectivity for the Electrochemical Reduction of Carbon Dioxide to Formic Acid and Carbon Monoxide on Metal Electrodes. Jeremy T. Feaster, C. Shi, Etosha R. Cave, T. Hatsukade, David N. Abram, Kendra P. Kuhl, Christopher Hahn, Jens K. Nørskov, Thomas F. Jaramillo . ACS Catalysis , 7 , 4822- 4827 . 2017. Electrochemical CO2 reduction on Au surfaces: mechanistic aspects regarding the formation of major and minor products. Etosha R. Cave, Joseph H. Montoya, Kendra P. Kuhl, David N. Abram, Toru Hatsukade, Chuan Shi, Christopher Hahn, Jens K. Nørskov, Thomas F. Jaramillo . Physical Chemistry Chemical Physics , 19 , 15856- 15863 . 2017.
Engineering Cu surfaces for the electrocatalytic conversion of CO2: Controlling selectivity toward oxygenates and hydrocarbons. Christopher Hahn, Toru Hatsukade, Youn-Geun Kim, Arturas Vailionis, Jack H. Baricuatro, Drew C. Higgins, Stephanie A. Nitopi, Manuel P. Soriaga, Thomas F. Jaramillo . Proceedings of the National Academy of Sciences , 114 , 5918- 5923 . 2017. Carbon Dioxide Electroreduction using a Silver–Zinc Alloy. Toru Hatsukade, Kendra P. Kuhl, Etosha R. Cave, David N. Abram, Jeremy T. Feaster, Anna L. Jongerius, Christopher Hahn, Thomas F. Jaramillo . Energy Technology , 5 , 955- 961 . 2017.
Development of a reactor with carbon catalysts for modular-scale, low-cost electrochemical generation of H 2 O 2. Zhihua Chen, Shucheng Chen, Samira Siahrostami, Pongkarn Chakthranont, Christopher Hahn, Dennis Nordlund, Sokaras Dimosthenis, Jens K. Nørskov, Zhenan Bao, Thomas F. Jaramillo . Reaction Chemistry & Engineering . 2017. Tandem Core-Shell Si–Ta3N5 Photoanodes for Photoelectrochemical Water Splitting. Ieva Narkeviciute, Pongkarn Chakthranont, Adriaan J. M. Mackus, Christopher Hahn, Blaise A. Pinaud, Stacey F. Bent, Thomas F. Jaramillo . Nano Letters , 16 , 7565- 7572 . 2016.