title: Dark Photocatalysis: Storage of Solar Energy in Carbon Nitride for Time-Delayed Hydrogen Generation.
abstract: While natural photosynthesis serves as the model system for efficient charge separation and decoupling of redox reactions, bio-inspired artificial systems typically lack applicability owing to synthetic challenges and structural complexity. We present herein a simple and inexpensive system that, under solar irradiation, forms highly reductive radicals in the presence of an electron donor, with lifetimes exceeding the diurnal cycle. This radical species is formed within a cyanamide-functionalized polymeric network of heptazine units and can give off its trapped electrons in the dark to yield H2, triggered by a co-catalyst, thus enabling the temporal decoupling of the light and dark reactions of photocatalytic hydrogen production through the radical's longevity. The system introduced here thus demonstrates a new approach for storing sunlight as long-lived radicals, and provides the structural basis for designing photocatalysts with long-lived photo-induced states.
authors.affiliation: Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart, Germany.|Department of Chemistry, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, Haus D, 81377, Munich, Germany.
authors.forename: Vincent Wing-Hei
authors.identifier: 0000-0003-4400-6781
authors.initials: VW
authors.lastname: Lau
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland.
authors.forename: Daniel
authors.identifier: 0000-0002-3597-0889
authors.initials: D
authors.lastname: Klose
authors.affiliation: Christian Doppler Laboratory for Sustainable SynGas Chemistry, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
authors.forename: Hatice
authors.identifier: 0000-0002-4288-839X
authors.initials: H
authors.lastname: Kasap
authors.affiliation: Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart, Germany.|Department of Chemistry, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, Haus D, 81377, Munich, Germany.|Ecole Polytechnique Féderale de Lausanne, Station 12, 1015, Lausanne, Switzerland.
authors.forename: Filip
authors.identifier: 0000-0002-5428-4526
authors.initials: F
authors.lastname: Podjaski
authors.affiliation: Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart, Germany.|Department of Chemistry, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, Haus D, 81377, Munich, Germany.|Sorbonne Universités, Université Pierre et Marie Curie, 4 place Jussieu, 75005, Paris, France.
authors.forename: Marie-Claire
authors.identifier: 0000-0001-6956-5876
authors.initials: MC
authors.lastname: Pignié
authors.affiliation: Christian Doppler Laboratory for Sustainable SynGas Chemistry, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
authors.forename: Erwin
authors.identifier: 0000-0002-7781-1616
authors.initials: E
authors.lastname: Reisner
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland.
authors.forename: Gunnar
authors.identifier: 0000-0001-6853-8585
authors.initials: G
authors.lastname: Jeschke
authors.affiliation: Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart, Germany.|Department of Chemistry, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, Haus D, 81377, Munich, Germany.
authors.forename: Bettina V
authors.identifier: 0000-0002-3094-303X
authors.initials: BV
authors.lastname: Lotsch
keywords: EPR spectroscopy; artificial photosynthesis; carbon nitrides; hydrogen evolution; stable radical