Optical and electrochemical effects of H2 and O2 bubbles at upward-facing Si photoelectrodes
| Autor: | Zachary P. Ifkovits, Paul A. Kempler, Weilai Yu, Azhar I. Carim, Nathan S. Lewis |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Renewable Energy Sustainability and the Environment Bubble Nucleation Analytical chemistry 02 engineering and technology Electrolyte Solar illumination 010402 general chemistry 021001 nanoscience & nanotechnology Electrochemistry 01 natural sciences Pollution 0104 chemical sciences Contact angle Planar Nuclear Energy and Engineering TRACER Environmental Chemistry 0210 nano-technology |
| Zdroj: | Energy & Environmental Science. 14:414-423 |
| ISSN: | 1754-5706 1754-5692 |
| Popis: | The effects of the size, contact-angle, and coverage of gas bubbles on solar fuels devices were characterized at cm-scale, upward-facing planar and microwire-array Si photoelectrodes in stagnant electrolytes. Experimental measurements were supported by ray-tracing simulations of surface attached gas bubble films. A dilute, redox-active tracer allowed for the quantification of the mass-transport effects of bubble coverage during photoanodic O2(g) evolution at upward-facing photoanodes in 1.0 M KOH(aq.). Measurements of the gas coverage at upward-facing p-Si photocathodes in 0.50 M H2SO4(aq.) allowed for the nucleation rate and contact angle of H2(g) bubbles to be evaluated for systems having various surface free energies. Under simulated solar illumination, the rapid departure of small O2(g) bubbles produced stable photocurrents at upward-facing oxygen-evolving Si photoanodes and yielded increased mass-transport velocities relative to a stagnant electrolyte, indicating that bubbles can provide a net benefit to the photoelectrochemical performance of an upward-facing photoanode in solar fuels devices. |
| Databáze: | OpenAIRE |
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