Reversible hydrogen storage using CO2 and a proton-switchable iridium catalyst in aqueous media unde

Abstract

Green plants convert CO2 to sugar for energy storage via photosynthesis. We report a novel catalyst that uses CO2 and hydrogen to store energy in formic acid. Using a homogeneous iridium catalyst with a proton-responsive ligand, we show the first reversible and recyclable hydrogen storage system that operates under mild conditions using CO2, formate and formic acid. This system is energy-efficient and green because it operates near ambient conditions, uses water as a solvent, produces high-pressure CO-free hydrogen, and uses pH to control hydrogen production or consumption. The extraordinary and switchable catalytic activity is attributed to the multifunctional ligand, which acts as a proton-relay and strong π-donor, and is rationalized by theoretical and experimental studies. When operating at near-ambient conditions, using water as a solvent, a high-turnover iridium catalyst enables a reversible hydrogen storage system that uses carbon dioxide, formate and formic acid. Proton-responsive ligands in the catalyst allow it to be turned on or off by controlling the pH of the solution.

Cite this article

Hull, J., Himeda, Y., Wang, WH. et al. Reversible hydrogen storage using CO₂ and a proton-switchable iridium catalyst in aqueous media under mild temperatures and pressures. Nature Chem 4, 383–388 (2012). https://doi.org/10.1038/nchem.1295

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