Abstract

Solar energy-powered water electrolysis is a cost-effective and scalable method to produce hydrogen, an environment-friendly and potentially sustainable energy carrier. To this end, we report a microchannel water electrolyzer with a planar design that can be integrated with a photovoltaic cell, where the electrolyzer utilizes the waste heat generated during the photoelectric process to enhance the production of hydrogen (and oxygen) via the electrochemical splitting of water. We performed a systematic parametric investigation to study the effect of the channel dimensions, electrolyte temperature and flow rate, and the mode of operation (pulsed vs. continuous) on the electrolyzer's performance. The balance between mass, heat and ion/charge transport limitations acts to determine an optimal geometry and specific operating conditions for the device. The highest hydrogen production rate was observed for pulsed operation (15 s pulses) at a temperature of 60 °C, and a potential of 2.0 V, for a 400-μm tall electrolyzer chamber. We also show that tuning of the geometry and operating conditions can yield an almost 7-fold increase in the hydrogen production rate. This study not only reports a new and improved approach over existing photovoltaic thermal systems but also presents design and operational considerations for microfluidic-based electrochemical energy devices.

Original languageEnglish (US)
Pages (from-to)122-128
Number of pages7
JournalJournal of Power Sources
Volume307
DOIs
StatePublished - Mar 1 2016

Keywords

  • Mass/heat/ion/charge transport limitation
  • PDMS electrolyzer
  • Photovoltaic thermal systems
  • Platinum black on gold electrodes
  • Pulsed operation for electrolyte transport

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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