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Published on: July 23, 2016
Atmospheric CO₂-to-acetaldehyde artificial photosynthesis in metallo hydrogen-bonded organic frameworks
Jun Pang1,2, Xinyu Bai3, Junjie Dai1,2
1National & Local Joint Engineering Laboratory for New Petro-Chemical Materials and Fine Utilization of Resources, Hunan Normal University, Changsha, Hunan, PR China.
Abstract:
Artificial photosynthesis of acetaldehyde from atmospheric CO2 is highly promising, yet remains severely limited by low CO2 concentration in air and sluggish proton transfer kinetics. Herein, we report metallo hydrogen-bonded organic frameworks (MHOFs) of HNNU-X (X = O, S, Se) which enable acetaldehyde synthesis directly from air, water, and natural sunlight. Among them, HNNU-Se exhibits a competitive acetaldehyde production rate of 557.1 μmol g⁻¹ h⁻¹ with high electron-based selectivity of 95% under outdoor conditions, without need of sacrificial agents. Mechanistic studies reveal that HNNU-X creates a proton-rich microenvironment in which [Zn(tpy)]2+ cations function as CO2 capture and activation sites for direct air capture, while [XCN]- anions serve as proton shuttles, facilitating rapid transfer of in-situ generated H⁺ from solar-driven water oxidation to adsorbed CO2. This work enables the synergistic coupling of CO2 reduction and H2O oxidation, thereby achieving efficient artificial photosynthesis of acetaldehyde.
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