Bio


Michael is a postdoctoral fellow whose interests encompass international development projects requiring productive energy use and how to increase their success through transdisciplinary approaches. He has a dual appointment in the Precourt Institute for Energy and the Department of Energy Resources Engineering. His current work focuses on understanding and reducing produce supply chain inefficiency in India from a systems perspective, while identifying and testing scalable interventions with on-the-ground partners and end-users. Michael completed a PhD in Materials Science and Engineering as an NSF Graduate Research Fellow at Stanford. His thesis focused on using fundamental research to develop design descriptors for improving solar-to-fuel and fuel-to-electricity conversion using electrochemistry.

Michael’s interest in social and environmental impact work began in high school as the president of the region’s youth-led tobacco free coalition. The coalition was runner-up for National Youth Advocates of the Year given by the Campaign for Tobacco Free Kids when Idaho (his home state) went tobacco-free. At Kenyon College, he self-designed a major in Chemical Physics to understand how related disciplines approach challenges in renewable energy technology development while co-captaining the men’s NCAA National Champion swim team.

After graduating in 2009, Michael moved to Germany as a Transatlantic Renewable Energy Fellow to research low-cost solar cells while learning about the sociopolitical environment that placed Germany as a global leader in renewable energy integration. While there, he attended the UNFCCC COP15 climate summit with two other fellows. Leading up to and during the highly anticipated event, they wrote and published an educational blog for the public. After leaving Germany, Michael lived in Southeast Asia as a Henry Luce Scholar to gain first-hand experience with renewable energy integration in unelectrified regions of Laos and Cambodia. This experience informed his desire to continue work on energy inequality and development around the world.

Professional Education


  • Bachelor of Arts, Kenyon College, Chemical Physics (2009)
  • Doctor of Philosophy, Stanford University, MATSC-PHD (2017)

All Publications


  • Redox activity of surface oxygen anions in oxygen-deficient perovskite oxides during electrochemical reactions. Nature communications Mueller, D. N., Machala, M. L., Bluhm, H., Chueh, W. C. 2015; 6: 6097-?

    Abstract

    Surface redox-active centres in transition-metal oxides play a key role in determining the efficacy of electrocatalysts. The extreme sensitivity of surface redox states to temperatures, to gas pressures and to electrochemical reaction conditions renders them difficult to investigate by conventional surface-science techniques. Here we report the direct observation of surface redox processes by surface-sensitive, operando X-ray absorption spectroscopy using thin-film iron and cobalt perovskite oxides as model electrodes for elevated-temperature oxygen incorporation and evolution reactions. In contrast to the conventional view that the transition metal cations are the dominant redox-active centres, we find that the oxygen anions near the surface are a significant redox partner to molecular oxygen due to the strong hybridization between oxygen 2p and transition metal 3d electronic states. We propose that a narrow electronic state of significant oxygen 2p character near the Fermi level exchanges electrons with the oxygen adsorbates. This result highlights the importance of surface anion-redox chemistry in oxygen-deficient transition-metal oxides.

    View details for DOI 10.1038/ncomms7097

    View details for PubMedID 25598003

  • Surface electrochemistry of CO2 reduction and CO oxidation on Sm-doped CeO2-x: coupling between Ce3+ and carbonate adsorbates PHYSICAL CHEMISTRY CHEMICAL PHYSICS Feng, Z. A., Machala, M. L., Chueh, W. C. 2015; 17 (18): 12273-12281

    Abstract

    The efficient electro-reduction of CO2 to chemical fuels and the electro-oxidation of hydrocarbons for generating electricity are critical toward a carbon-neutral energy cycle. The simplest reactions involving carbon species in solid-oxide fuel cells and electrolyzer cells are CO oxidation and CO2 reduction, respectively. In catalyzing these reactions, doped ceria exhibits a mixed valence of Ce(3+) and Ce(4+), and has been employed as a highly active and coking-resistant electrode. Here we report an operando investigation of the surface reaction mechanism on a ceria-based electrochemical cell using ambient pressure X-ray photoelectron spectroscopy. We show that the reaction proceeds via a stable carbonate intermediate, the coverage of which is coupled to the surface Ce(3+) concentration. Under CO oxidation polarization, both the carbonate and surface Ce(3+) concentration decrease with overpotential. Under CO2 reduction polarization, on the other hand, the carbonate coverage saturates whereas the surface Ce(3+) concentration increases with overpotential. The evolution of these reaction intermediates was analyzed using a simplified two-electron reaction scheme. We propose that the strong adsorbate-adsorbate interaction explains the coverage-dependent reaction mechanism. These new insights into the surface electrochemistry of ceria shed light on the optimization strategies for better fuel cell electrocatalysts.

    View details for DOI 10.1039/c5cp00114e

    View details for Web of Science ID 000353767500038

    View details for PubMedID 25891363

  • On-substrate polymerization of solution-processed, transparent PEDOT: DDQ thin film electrodes with a hydrophobic polymer matrix ORGANIC ELECTRONICS Machala, M. L., Mueller-Meskamp, L., Gang, S., Olthof, S., Leo, K. 2011; 12 (9): 1518-1526