Hydrogen production from renewable energy and ubiquitous water has a potential to achieve sustainability, although current water electrolyzers cannot compete economically with the fossil fuel-based technology. Here, we evaluate water electrolysis at pH 7 that is milder than acidic and alkaline pH counterparts and may overcome this issue. The physicochemical properties of concentrated buffer electrolytes were assessed at various temperatures and molalities for quantitative determination of losses associated with mass-transport during the water electrolysis. Subsequently, in saturated K-phosphate solutions at 80 °C and 100 °C that were found to be optimal to minimize the losses originating from mass-transport at the neutral pH, the water electrolysis performance over model electrodes of IrOx and Pt as an anode and a cathode, respectively, was reasonably comparable with those of the extreme pH. Remarkably, this concentrated buffer solution also achieved enhanced stability, adding another merit of this electrolyte for water electrolysis.
|Original language||English (US)|
|State||Published - Oct 27 2020|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-29
Acknowledged KAUST grant number(s): OSR #4191
Acknowledgements: A part of this work was supported by JSPS KAKENHI Grant Number 19 K23569 and UTokyo-KAUST collaborative research OSR #4191 “Towards Sustainable Production of H2”.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.