Interfacial Microenvironment Engineering Using Zr-Based Materials for High-Rate CO2 Electroreduction

Jun Tae Song^a^,^b, Yuta Takaoka^a, Motonori Watanabe^a^,^b, Miki Inada^a^,^b, Tatsumi Ishihara^a^,^b

^aDepartment of Applied Chemistry, Kyushu University

^bInternational Institute for Carbon-neutral Energy Research (WPI-I2CNER), Kyushu University

Proceedings of MATSUS Fall 2026 Conference (MATSUSFall26)

E4 Advances and Innovations in (Photo)Electrochemical CO2 and N2 Conversion and Water Splitting

Palma, Spain, 2026 October 26th - 30th

Organizer: Guillermo Díaz-Sainz

Oral, Jun Tae Song, presentation 195
Publication date: 22nd July 2026

Low-temperature electrochemical CO₂ reduction reaction (CO₂RR) is a promising strategy for producing formic acid, an attractive liquid hydrogen carrier and value-added chemical. Although Bi-based catalysts are highly selective toward formate, their CO₂ conversion rate remains limited under practical electrolysis conditions. To address this issue, we initially proposed a Zr-MOF-assisted Bi catalyst design, aiming to enhance the local CO₂ availability near Bi active sites through microenvironment modulation.

First, we proposed the novel Bi with Zr-MOF (UiO-66) catalysts structure as a strategy to enhance CO₂ availability. Bi was deposited on UiO-66, a Zr-based MOF, and evaluated for CO₂RR in a flow-cell reactor under continuous CO₂ supply. The Bi/UiO-66 catalyst exhibited a 2.5–3.0-fold increase in current density compared with Bi alone while maintaining comparable Faradaic efficiency for formate production. This result suggested that the incorporation of Zr-containing components can effectively promote CO₂ conversion at Bi catalysts. However, post-electrolysis structural analyses revealed that the original UiO-66 framework was not fully retained during electrolysis. Instead, carbonate-coordinated Zr-hydroxide species were formed, indicating that the enhanced activity originates not simply from the intact MOF structure, but rather from the role of Zr-derived species in the interfacial reaction environment.

To verify this concept, Bi–Zr composite catalysts were further investigated as model systems to clarify the function of Zr species. These catalysts showed significantly higher CO₂RR current density than Bi-only electrodes. In situ Raman spectroscopy revealed a lowered surface pH for the optimized Bi/Zr composition, suggesting increased local CO₂ availability near the catalyst surface. These findings demonstrate that Zr-derived components actively modulate the CO₂ microenvironment around Bi sites, thereby improving high-rate CO₂-to-formate conversion. This study highlights Zr-based interfacial microenvironment engineering as an effective strategy for overcoming local reactant limitations in CO₂ electroreduction.

References:

[1] Takaoka, Y; Song, J. T,; Takagaki, A, Watanabe, M; Ishihara, T, Bi/UiO-66-derived electrocatalysts for high CO2-to-formate conversion rate, Appl. Catal. B: Environ. 2023, 326, 122400.

[2] Takaoka, Y; Choi, E.; Kim H-Y.; Song, J. T., Kim, H. S.; Watanabe, M.; Inada, M.; Ishihara, T.; ChemSusChem. 2025, 18, e202501024

Acknowledgements:

This work was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI (grant nos. 24K08580 [Kiban C] and 24H00486 [Kiban A]). Also, it was partly supported by Japan Science and Technology Agency (JST) and the Aspire Program (grant numbers: JPMJAP2308.

nanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. Our worldwide conferences cover cutting-edge materials topics like perovskite solar cells, photovoltaics, optoelectronics, solar fuel conversion, surface science, catalysis and two-dimensional materials, among many others.

MATSUS

Previously nanoGe Spring Meeting (NSM) and nanoGe Fall Meeting (NFM), MATSUS is a multiple symposia conference focused on a broad set of topics of advanced materials preparation, their fundamental properties, and their applications, in fields such as renewable energy, photovoltaics, lighting, semiconductor quantum dots, 2-D materials synthesis, charge carriers dynamics, microscopy and spectroscopy semiconductors fundamentals, etc.

International Conference on Hybrid and Organic Photovoltaics

International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.

Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics

The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.

International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics

The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.