An artificial leaf device built with earth-abundant materials for combined H2 production and storage as formate with efficiency > 10%


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Date

2023-04

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

A major challenge for achieving energy transition and transforming the current energy model into distributed production is the development of efficient artificial leaf-type devices capable of directly converting carbon dioxide (CO2), water and sunlight into sustainable fuels and chemicals under ambient conditions. These devices should avoid using critical raw materials to be sustainable and cost-competitive. We report top-level results for the first time in converting CO2 and H2O to fuels (formate and H-2) using sunlight and electrodes based solely on earth-abundant materials. The cell provides a solar-to-fuel efficiency of >10% combined with world-record current densities to comparable devices operating at room temperature, without adding sacrificial donors or electrical bias. In addition, we present the novel concept of producing at the same time H-2 and an H-2-storage element (formate), the latter used to produce H-2 when light is absent. This solution allows continuous (24 h) hydrogen production using an artificial-leaf device. For the first time, we show the feasibility of this solution. The experimental results were obtained in an optimised, compact electrochemical flow cell, with electrodes based on Cu-S and Ni-Fe-Zn oxide (for CO2 reduction and oxygen evolution reactions, respectively) supported on gas-diffusion substrates, integrated with a low-cost Si-based photovoltaic module. The cell design allows for easy scale-up and low manufacturing and operating costs. The cell operates at a current density of about 17 mA cm(-2) and a full-cell voltage of 2.5 V (stable for at least ten hours and in on-off operations), providing formate productivity of 193 mu mol h(-1) cm(-2), paving the way towards the implementation of affordable artificial-leaf type systems in the future energy scenario.

Publication status

published

Editor

Book title

Volume

16 (4)

Pages / Article No.

1644 - 1661

Publisher

Royal Society of Chemistry

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Edition / version

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Subject

Organisational unit

03871 - Pérez-Ramírez, Javier / Pérez-Ramírez, Javier check_circle

Notes

Funding

732840 - An Artificial Leaf: a photo-electro-catalytic cell from earth-abundant materials for sustainable solar production of CO2-based chemicals and fuels (EC)
ETH-47 19-1 - Microstructured electrocatalysts as a design platform for decentralized ammonia synthesis and carbon dioxide fixation in artificial leaves (ETHZ)

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