Solar-to-hydrogen photoelectrochemical cells (PECs) have been proposed as a means of converting sunlight into H2 fuel. However, in traditional PECs, the oxygen evolution reaction and the hydrogen evolution reaction are coupled and so the rate of both of these is limited by the photocurrents that can be generated from the solar flux. This in turn leads to slow rates of gas evolution that favor cross-over of H2 into the O2 stream and vice-versa, even through ostensibly impermeable membranes such as Nafion. In our work we have found that the use of both organic and inorganic Electron-Coupled-Proton buffers allows the solar-driven O2 evolution from water. No H2 is produced in the PEC, and instead buffer is reduced and protonated. If the reduced Electron-Coupled-Proton buffer is then subjected to a separate electrochemical re-oxidation, H2 is produced often with full overall Faradaic efficiency.

Solar-driven water oxidation and decoupled hydrogen production mediated by an electron-coupled-proton buffer

253rd National Meeting (2017)

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