3 ms·

Gated suppression of light-driven proton transport through graphene electrodes

2 points by westurner 3y ago

westurner 3y ago
"Gate-controlled suppression of light-driven proton transport through graphene electrodes" (2023) https://www.nature.com/articles/s41467-023-42617-4 https://www.nature.com/articles/s41467-023-42617-4 : > Abstract: Recent experiments demonstrated that proton transport through graphene electrodes can be accelerated by over an order of magnitude with low intensity illumination. Here we show that this photo-effect can be suppressed for a tuneable fraction of the infra-red spectrum by applying a voltage bias. Using photocurrent measurements and Raman spectroscopy, we show that such fraction can be selected by tuning the Fermi energy of electrons in graphene with a bias, a phenomenon controlled by Pauli blocking of photo-excited electrons. These findings demonstrate a dependence between graphene’s electronic and proton transport properties and provide fundamental insights into molecularly thin electrode-electrolyte interfaces and their interaction with light.
- westurner 3y ago
  "Graphene proton transport could revolutionize renewable energy" (2023) https://interestingengineering.com/science/graphene-proton-transport-could-revolutionize-renewable-energy https://interestingengineering.com/science/graphene-proton-t... : > Scientists have found a way to speed up proton transport across graphene using light. The innovation could open up new avenues to producing green hydrogen.
westurner 3y ago
Perhaps tangentially, "Cheap proton batteries compete with lithium on energy density" (2023) https://news.ycombinator.com/item?id=36926123 https://news.ycombinator.com/item?id=36926123 : "Enhancement of the performance of a proton battery" (2023) https://www.sciencedirect.com/science/article/abs/pii/S0378775322007972 https://www.sciencedirect.com/science/article/abs/pii/S03787... : > Abstract: The present paper reports on experiments to improve theoretical understanding of the basic processes underlying the operation of a ‘proton battery’ with activated carbon as a hydrogen storage electrode. Design changes to enhance energy storage capacity and power output have been identified and investigated experimentally. Key changes made were heating of the overall cell to 70 °C, and replacement of the oxygen-side gas diffusion layer with a much thinner titanium-fibre sheet. A very substantial increase in reversible hydrogen storage capacity to 2.23 wt%H (598 mAh g−1, 882 J g−1) was achieved. This capacity is nearly three times that of the earlier design, and more than double the highest electrochemical hydrogen storage using an acidic electrolyte previously reported. It is hypothesised that the main cause of the major gain in storage is an enhanced water formation reaction on the O-side through reduced flooding. In addition, an alternative mode of discharging a proton battery has been discovered that allows direct generation of hydrogen gas from the hydrogenated carbon material, by a ‘hydrogen-pump’ type of reaction. The hydrogen gas evolved is high purity, and thus may ultimately create opportunities for use of this storage technology in hydrogen supply chains for fuel cell vehicles. [And probably other applications as well] (Edit) A combined proton battery + graphene proton hydrolysis unit should probably keep the hydrolysis module as a separate part for replaceability?

2 points by westurner 3y ago

"Gate-controlled suppression of light-driven proton transport through graphene electrodes" (2023) https://www.nature.com/articles/s41467-023-42617-4 https://www.nature.com/articles/s41467-023-42617-4 : > Abstract: Recent experiments demonstrated that proton transport through graphene electrodes can be accelerated by over an order of magnitude with low intensity illumination. Here we show that this photo-effect can be suppressed for a tuneable fraction of the infra-red spectrum by applying a voltage bias. Using photocurrent measurements and Raman spectroscopy, we show that such fraction can be selected by tuning the Fermi energy of electrons in graphene with a bias, a phenomenon controlled by Pauli blocking of photo-excited electrons. These findings demonstrate a dependence between graphene’s electronic and proton transport properties and provide fundamental insights into molecularly thin electrode-electrolyte interfaces and their interaction with light.

westurner 3y ago
"Graphene proton transport could revolutionize renewable energy" (2023) https://interestingengineering.com/science/graphene-proton-transport-could-revolutionize-renewable-energy https://interestingengineering.com/science/graphene-proton-t... : > Scientists have found a way to speed up proton transport across graphene using light. The innovation could open up new avenues to producing green hydrogen.

westurner 3y ago

Perhaps tangentially, "Cheap proton batteries compete with lithium on energy density" (2023) https://news.ycombinator.com/item?id=36926123 https://news.ycombinator.com/item?id=36926123 : "Enhancement of the performance of a proton battery" (2023) https://www.sciencedirect.com/science/article/abs/pii/S0378775322007972 https://www.sciencedirect.com/science/article/abs/pii/S03787... : > Abstract: The present paper reports on experiments to improve theoretical understanding of the basic processes underlying the operation of a ‘proton battery’ with activated carbon as a hydrogen storage electrode. Design changes to enhance energy storage capacity and power output have been identified and investigated experimentally. Key changes made were heating of the overall cell to 70 °C, and replacement of the oxygen-side gas diffusion layer with a much thinner titanium-fibre sheet. A very substantial increase in reversible hydrogen storage capacity to 2.23 wt%H (598 mAh g−1, 882 J g−1) was achieved. This capacity is nearly three times that of the earlier design, and more than double the highest electrochemical hydrogen storage using an acidic electrolyte previously reported. It is hypothesised that the main cause of the major gain in storage is an enhanced water formation reaction on the O-side through reduced flooding. In addition, an alternative mode of discharging a proton battery has been discovered that allows direct generation of hydrogen gas from the hydrogenated carbon material, by a ‘hydrogen-pump’ type of reaction. The hydrogen gas evolved is high purity, and thus may ultimately create opportunities for use of this storage technology in hydrogen supply chains for fuel cell vehicles. [And probably other applications as well] (Edit) A combined proton battery + graphene proton hydrolysis unit should probably keep the hydrolysis module as a separate part for replaceability?