Design principles of tandem cascade photoelectrochemical devices

Kong, Calton J.; Warren, Emily L.; Greenaway, Ann L.; Prabhakar, Rajiv Ramanujam; Tamboli, Adele C.; Ager, Joel W.

doi:10.1039/d1se01322j

“…Photoelectrochemical carbon dioxide reduction (PEC CO 2 R) is a promising route to recycling captured CO 2 in the form of liquid chemical fuels using sunlight as the energy input. Practical PEC CO 2 R systems will require the development of multiple components, including high-performing catalysts, separation membranes, and coupled microenvironments, , as well as the integration and scale-up of these materials and processes . A critical factor for the future success of PEC CO 2 R is the identification of suitable photoelectrode materials to convert photons to electrons to drive CO 2 R as well as the oxygen evolution reaction (OER) that enables the production of fuel using only CO 2 and H 2 O as reactants. , Like semiconductors used in photovoltaics, these photoabsorbers are subject to stringent requirements of strong absorptivity, long carrier lifetimes, and appropriate band gap, but with the added constraints of band edge positions that can drive the reaction of interest, suitable adsorption/desorption kinetics at the surface, and, critically, operational stability in aqueous environments. , …”

Section: Introductionmentioning

confidence: 99%

“…Photoelectrochemical carbon dioxide reduction (PEC CO 2 R) is a promising route to recycling captured CO 2 in the form of liquid chemical fuels using sunlight as the energy input. Practical PEC CO 2 R systems will require the development of multiple components, including high-performing catalysts, 1 separation membranes, 2 and coupled microenvironments, 3,4 as well as the integration and scale-up of these materials and processes. 5 A critical factor for the future success of PEC CO 2 R is the identification of suitable photoelectrode materials to convert photons to electrons to drive CO 2 R as well as the oxygen evolution reaction (OER) that enables the production of fuel using only CO 2 and H 2 O as reactants.…”

Section: Introductionmentioning

confidence: 99%

Zinc Titanium Nitride Semiconductor toward Durable Photoelectrochemical Applications

Greenaway

¹

,

Ke

²

,

Culman

³

et al. 2022

Self Cite

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Photoelectrochemical fuel generation is a promising route to sustainable liquid fuels produced from water and captured carbon dioxide with sunlight as the energy input. Development of such technologies requires photoelectrode materials that are both photocatalytically active and operationally stable in harsh oxidative and/or reductive electrochemical environments. Such photocatalysts can be discovered based on co-design principles, wherein design for stability is based on the propensity for the photocatalyst to self-passivate under operating conditions and design for photoactivity is based on the ability to integrate the photocatalyst with established semiconductor substrates. Here we report on synthesis and characterization of zinc titanium nitride (ZnTiN 2 ) that follows these design rules by having a wurtzite-derived crystal structure and showing self-passivating surface oxides created by electrochemical polarization. The sputtered ZnTiN 2 thin films have optical absorption onsets below 2 eV and n-type electrical conduction of 0.1 S/cm. The band gap of this material is reduced from the 3.5 eV theoretical value by cation site disorder, and the impact of cation antisites on the band structure of ZnTiN 2 is explored using density functional theory. Under electrochemical polarization, the ZnTiN 2 surfaces have TiO 2 -or ZnO-like character, consistent with Materials Project Pourbaix calculations predicting the formation of stable solid phases under near-neutral pH. These results show that ZnTiN 2 is a promising candidate for photoelectrochemical liquid fuel generation and demonstrate a new materials design approach to other photoelectrodes with self-passivating native operational surface chemistry. Broader ImpactPhotoelectrochemical fuel generation has been stymied by a lack of photoelectrode materials which are both highly active and stable under long-term operation. Searches for new photoelectrodes have typically selected either stability or activity, with the intent to improve the other characteristic after the fact. Inspired by technologies that employ designed surface transformations for operational stability, such as the precipitation strengthening of Ni-based superalloys in gas turbines, here we employ co-design principles to identify a candidate photoelectrode material which can fill both stability and activity requirements. We synthesize this promising candidate photoelectrode material, ZnTiN2, which forms stable protective oxides under electrochemical operation, providing a route to stability, while being structurally compatible with established semiconductors, enabling good optoelectronic properties. We investigate the optoelectronic properties and electrochemical stability of ZnTiN2 both experimentally and computationally. These results confirm the promise of ZnTiN2 as a photoelectrode material and point to a successful new materials design strategy for photoelectrode development.

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“…Therefore, studies , have proposed the solar fuel approach where CO 2 reduction to a multi-electron liquid fuel is broken up into a two-electron-transfer reaction step of CO 2 reduction to CO and a subsequent step of CO reduction to a multi-electron liquid fuel. This approach has been analyzed to have a higher efficiency limit than the one-step CO 2 reduction; see Supporting Information for more details.…”

Section: Theoretical Preparationmentioning

confidence: 99%

“…2−5 However, excessive overpotentials, due to the basic scaling relationship, are required for the direct reduction of CO 2 into multi-electron liquid fuels; 6,7 highly selective CO 2 reduction into a specific multi-electron product is also challenging. 8−10 Therefore, studies 11,12 have proposed the solar fuel approach where CO 2 reduction to a multi-electron liquid fuel is broken up into a two-electron-transfer reaction step of CO 2 reduction to CO and a subsequent step of CO reduction to a multielectron liquid fuel. This approach has been analyzed to have a higher efficiency limit than the one-step CO 2 reduction; 11 see Supporting Information for more details.…”

mentioning

confidence: 99%

Photovoltaic-Powered Electrochemical CO₂ Reduction: Benchmarking against the Theoretical Limit

Liu

¹

,

Ma

²

,

Feng

³

et al. 2023

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In this work, benchmarking against the theoretical limit and against water splitting was used to indicate the promise of photovoltaic-powered electrochemical CO 2 reduction. A benchmark device was built by the successful integration of high-performance cathode, anode, membrane-electrodeassembly reactor and dual-junction photoabsorber. This is the first report on dual-junction photoabsorber-driven CO 2 electrolysis. We experimentally demonstrated a record-high solar-to-chemical energy conversion efficiency of 21.3% and a projected efficiency of 25.3%. This performance metric remarkably reaches 87% of the theoretical efficiency limit and surpasses the solar-to-hydrogen efficiency based on the same photoabsorber. This work paves the way for efficient solar fuel production with solar CO as the intermediate.

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“…Photoelectrochemical carbon dioxide reduction (PEC CO2R) is a promising route to recycling captured CO2 in the form of liquid chemical fuels using sunlight as the energy input. Practical PEC CO2R systems will require the development of multiple components, including high-performing catalysts, 1 separation membranes, 2 and coupled microenvironments, 3,4 as well as the integration and scale-up of these materials and processes. 5 A critical factor for the future success of PEC CO2R is the identification of suitable photoelectrode materials to convert photons to electrons to drive CO2R as well as the oxygen evolution reaction (OER) that enables the production of fuel using only CO2 and H2O as reactants.…”

Section: Introductionmentioning

confidence: 99%

Co-design of zinc titantium nitride semiconductor towards durable photoelectrochemical applications

Greenaway

¹

,

Ke

²

,

Culman

³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

Photoelectrochemical fuel generation is a promising route to sustainable liquid fuels produced from water and captured carbon dioxide with sunlight as the energy input. Development of such technologies requires photoelectrode materials that are both photocatalytically active and operationally stable in harsh oxidative and/or reductive electrochemical environments. Such photocatalysts can be discovered based on co-design principles, wherein design for stability is based on the propensity for the photocatalyst to self-passivate under operating conditions and design for photoactivity is based on the ability to integrate the photocatalyst with established semiconductor substrates. Here we report on synthesis and characterization of zinc titanium nitride (ZnTiN2) that follows these design rules by having a wurtzite-derived crystal structure and showing self-passivating surface oxides created by electrochemical polarization. The sputtered ZnTiN2 thin films have optical absorption onsets below 2 eV and n-type electrical conduction of 0.1 S/cm. The band gap of this material is reduced from the 3.5 eV theoretical value by cation site disorder, and the impact of cation antisites on the band structure of ZnTiN2 is explored using density functional theory. Under electrochemical polarization, the ZnTiN2 surfaces have TiO2- or ZnO-like character, consistent with Materials Project Pourbaix calculations predicting the formation of stable solid phases under near-neutral pH. These results show that ZnTiN2 is a promising candidate for photoelectrochemical liquid fuel generation and demonstrate a new materials design approach to other photoelectrodes with self-passivating native operational surface chemistry.

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Design principles of tandem cascade photoelectrochemical devices

Abstract: The design principles for tandem cascade photoelectrocatalysis are developed using CO2 reduction as a model system.

Cited by 10 publications

References 50 publications

Zinc Titanium Nitride Semiconductor toward Durable Photoelectrochemical Applications

Zinc Titanium Nitride Semiconductor toward Durable Photoelectrochemical Applications

Photovoltaic-Powered Electrochemical CO₂ Reduction: Benchmarking against the Theoretical Limit

Co-design of zinc titantium nitride semiconductor towards durable photoelectrochemical applications

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Design principles of tandem cascade photoelectrochemical devices

Abstract: The design principles for tandem cascade photoelectrocatalysis are developed using CO2 reduction as a model system.

Cited by 10 publications

References 50 publications

Zinc Titanium Nitride Semiconductor toward Durable Photoelectrochemical Applications

Zinc Titanium Nitride Semiconductor toward Durable Photoelectrochemical Applications

Photovoltaic-Powered Electrochemical CO2 Reduction: Benchmarking against the Theoretical Limit

Co-design of zinc titantium nitride semiconductor towards durable photoelectrochemical applications

Contact Info

Product

Resources

About

Photovoltaic-Powered Electrochemical CO₂ Reduction: Benchmarking against the Theoretical Limit