Solar Reactors & Electrochemical Cells

Topic #3: Membraneless (Photo)electrochemical cells and reactors

glen-membraneless-reactor
(left) Schematic top view of membraneless electrolyzer based on angled mesh flow through electrodes. (right) Photograph of 3D printed membraneless electrolyzer with window on top for in situ imaging by high-speed video. More details can be found in publication [5].
As engineers, we are not only intrigued by the fundamental science involved in our research, but also seek to apply that knowledge to the invention, design, optimization, and scale-up of real-world devices and systems.  In this spirit, an important part of research in our lab involves the development of (photo)electrochemical and PV-electrolysis devices, reactors, and systems. Evaluation of the performance of integrated devices and systems can be invaluable for gaining an understanding of the complex interplay that often exists between components and is crucial for optimization and scale-up processes.

Of particular interest in our group are novel membraneless PEC and electrochemical reactors, which offer exciting opportunities to decrease capital costs through their simplicity. Additionally, membrane-free devices have potential advantages in terms of durability and electrolyte flexibility that can enable electrolyzers to be used in new operating regimes and/or applications. Two key aspects of of our device-level research are (i) Additive manufacturing (3D-printing), which has proven to be invaluable for accelerating the development of electrochemical and photoelectrochemical test cells and reactors, and (ii.) Incorporation of windows and electrochemical sensors into these devices. The former features enable in situ studies of the fluid dynamics and bubble dynamics within these devices using high speed video (HSV). These measurements are carried out in close collaboration with electrochemical engineering (modeling) and CFD experts to validate models and develop design guidelines for these devices.

High speed video of H2 and O2 gas bubble evolution from Platinized Ti mesh operating in 0.5 M H2SO4 at 150 mA/cm^2. By coating the Pt electrocatalyst only on the outer surfaces of the mesh electrode (left video), gas bubbles can be collected with product purities as high as 99% while the holes in the porous mesh electrode still allow for ions to transport between the anode and cathode. Complete details can be found in reference [1]. Videos taken by Jack Davis. Video formatting credited to a Columbia University press release.

Publications:

  1. J.T. Davis, J. Qi, X. Fan, J. Bui, D.V. Esposito, “Floating Membraneless PV-Electrolyzer Based on Buoyancy-Driven Product Separation”,  International Journal of Hydrogen Energy, vol. 43 (3), pp 1224–1238, 2018. Download here. Highlighted in a Columbia University press release.
  2. D.V. Esposito, “Membraneless Electrolyzers for Low-Cost Hydrogen Production in a Renewable Energy Future”. Joule, 1, 1-8, 2017. (Perspective) Download here.
  3. O.O. Talabi, A.E. Dorfi, G.D. O’Neil, D.V. Esposito, “Membraneless Electrolyzers for the Simultaneous Production of Acid and Base”. Chemical Communications, 53, 8006-8009 2017. Part of the 2017 Emerging Investigators Issue. Download here.
  4. J.T. Davis, D.V. Esposito, “Limiting Photocurrent Analysis of a Wide Channel Photoelectrochemical Flow Reactor”,  Journal of Physics D: Applied Physics.,  vol. 50, 8, 11 pp, 2017. (Special Issue on Solar Fuels). Available for download here.
  5. G.D. O’Neil, C. Christian, D.E. Brown, D.V. Esposito, “Hydrogen Production with a Simple and Scalable Membraneless Electrolyzer”. Journal of the Electrochemical Society, 162, F3012-F3019, 2016. Download  here (Open Access).