Copper Tantalate by a Sodium-Driven Flux-Mediated Synthesis for Photoelectrochemical CO2 Reduction

Ariadne Köche; Kootak Hong; Sehun Seo; Finn Babbe; Hyeongyu Gim; Keon-Han Kim; Hojoong Choi; Yoonsung Jung; Inhyeok Oh; Gnanavel Vaidhyanathan Krishnamurthy; Michael Störmer; Sanghan Lee; Tae-Hoon Kim; Alexis T Bell; Sherdil Khan; Carolin M Sutter-Fella; Francesca M Toma

doi:10.1002/smtd.202401432

Copper Tantalate by a Sodium-Driven Flux-Mediated Synthesis for Photoelectrochemical CO₂ Reduction

Small Methods. 2025 Jan 15:e2401432. doi: 10.1002/smtd.202401432. Online ahead of print.

Authors

Ariadne Köche^{1

2}, Kootak Hong³, Sehun Seo^{1

4

5}, Finn Babbe^{1

4}, Hyeongyu Gim³, Keon-Han Kim^{1

4

6}, Hojoong Choi⁵, Yoonsung Jung⁷, Inhyeok Oh⁷, Gnanavel Vaidhyanathan Krishnamurthy⁵, Michael Störmer⁵, Sanghan Lee⁷, Tae-Hoon Kim³, Alexis T Bell^{1

4

6}, Sherdil Khan², Carolin M Sutter-Fella⁸, Francesca M Toma^{1

4

5}

Affiliations

¹ Liquid Sunlight Alliance, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, 94720, United States.
² Postgraduate Program in Materials Science, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre, RS, 91540-000, Brazil.
³ Department of Materials Science and Engineering, Chonnam National University, Gwangju, 61186, Republic of Korea.
⁴ Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, 94720, United States.
⁵ Institute of Functional Materials for Sustainability, Helmholtz-Zentrum Hereon, Kantstraße 55, 14513, Teltow, Germany.
⁶ Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, CA, 94720, United States.
⁷ School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea.
⁸ Molecular Foundry Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA, 94720, United States.

PMID: 39815160
DOI: 10.1002/smtd.202401432

Abstract

Copper-tantalate, Cu₂Ta₄O₁₁ (CTO), shows significant promise as an efficient photocathode for multi-carbon compounds (C₂₊) production through photoelectrochemical (PEC) CO₂ reduction, owing to its suitable energy bands and catalytic surface. However, synthesizing CTO poses a significant challenge due to its metastable nature and thermal instability. In this study, this challenge is addressed by employing a flux-mediated synthesis technique using a sodium-based flux to create sodium-doped CTO (Na-CTO) thin films, providing enhanced nucleation and stabilization for the CTO phase. To evaluate the PEC performance and catalytic properties of the films, copper(II) oxide (CuO) at the Na-CTO surface is selectively etched. The etched Na-CTO shows a lower dark current, with decreased contribution from photocorrosion, unlike the non-etched Na-CTO which has remaining CuO on the surface. Furthermore, Na-CTO exhibits 7.3-fold ethylene selectivity over hydrogen, thus highlighting its promising potential as a photocathode for C₂₊ production through PEC CO₂ reduction.

Keywords: copper tantalate; flux‐mediated synthesis; photoelectrochemical CO2 reduction.

Abstract

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