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Kim D, Lim H, Seo M, Shin H, Kim K, Jung M, Jang S, Chae B, Park B, Lee J, Choi Y, Kim KJ, Kim J, Tong X, Hunt A, Waluyo I, Mun BS. Study of CO 2 Adsorption Properties on the SrTiO 3(001) Surface with Ambient Pressure XPS. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 38982984 DOI: 10.1021/acsami.4c04729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
The adsorption properties of CO2 on the SrTiO3(001) surface were investigated using ambient pressure X-ray photoelectron spectroscopy under elevated pressure and temperature conditions. On the Nb-doped TiO2-enriched (1 × 1) SrTiO3 surface, CO2 adsorption, i.e., the formation of CO3 surface species, occurs first at the oxygen lattice site under 10-6 mbar CO2 at room temperature. The interaction of CO2 molecules with oxygen vacancies begins when the CO2 pressure increases to 0.25 mbar. The adsorbed CO3 species on the Nb-doped SrTiO3 surface increases continuously as the pressure increases but starts to leave the surface as the surface temperature increases, which occurs at approximately 373 K on the defect-free surface. On the undoped TiO2-enriched (1 × 1) SrTiO3 surface, CO2 adsorption also occurs first at the lattice oxygen sites. Both the doped and undoped SrTiO3 surfaces exhibit an enhancement of the CO3 species with the presence of oxygen vacancies, thus indicating the important role of oxygen vacancies in CO2 dissociation. When OH species are removed from the undoped SrTiO3 surface, the CO3 species begin to form under 10-6 mbar at 573 K, thus indicating the critical role of OH in preventing CO2 adsorption. The observed CO2 adsorption properties of the various SrTiO3 surfaces provide valuable information for designing SrTiO3-based CO2 catalysts.
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Affiliation(s)
- Dongwoo Kim
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Hojoon Lim
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Minsik Seo
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Hyunsuk Shin
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Kyungmin Kim
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Moonjung Jung
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Subin Jang
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Byunghyun Chae
- Gwangju Science Academy for the Gifted, Gwangju 61005, Republic of Korea
| | - Buseung Park
- Gwangju Science Academy for the Gifted, Gwangju 61005, Republic of Korea
| | - Jungwoo Lee
- Gwangju Science Academy for the Gifted, Gwangju 61005, Republic of Korea
| | - Yongseok Choi
- Gwangju Science Academy for the Gifted, Gwangju 61005, Republic of Korea
| | - Ki-Jeong Kim
- Pohang Accelerator Laboratory, POSTECH, Pohang-si, Gyeongsangbuk-do 37673, Republic of Korea
| | - Jeongjin Kim
- Pohang Accelerator Laboratory, POSTECH, Pohang-si, Gyeongsangbuk-do 37673, Republic of Korea
| | - Xiao Tong
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Adrian Hunt
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Iradwikanari Waluyo
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Bongjin Simon Mun
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
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Bhat AY, Jain P, Bhat MA, Ingole PP. Mechanistic insights into the electrolyte effects on the electrochemical nitrogen reduction reaction using copper hexacyanoferrate/f-MWCNT nano-composites. Phys Chem Chem Phys 2024; 26:1777-1791. [PMID: 38168681 DOI: 10.1039/d3cp04302a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Developing an efficient, selective, and stable electrocatalysis system for the electrocatalytic N2 reduction reaction (ENRR) is a promising strategy for the green and sustainable production of ammonia. The activity, selectivity, and stability of various electrocatalysts in different electrolyte solvents, mainly acidic and alkaline electrolytes, are commonly compared in the literature. However, a mechanistic insight into the effect of these electrolytes on ENRR activity is lacking. Herein we demonstrate that the acidity or alkalinity of the electrolyte is a key factor in determining the rate-limiting step and, by extension, the ENRR performance of an electrochemical setup for the electroproduction of ammonia. Our results from ex situ X-ray photoelectron, Raman, and FTIR spectroscopy analysis of the fresh and spent Cu-hexacyanoferrate Prussian blue analogue-decorated functionalized carbon nanotube (CuFe PBA/f-CNT) catalyst reveal that NH4+-species are more strongly adsorbed on the catalyst surface during the ENRR in acidic than in alkaline electrolytes. The results of our detailed rotating ring-disc electrode voltammetry studies suggest that the ENRR over CuFe PBA/f-CNT is mostly controlled by surface adsorption in an acidic electrolyte and by mass transport in an alkaline electrolyte. In situ Raman spectroscopy confirms this finding and shows that the leaching of Fe(CN)6 species from the CuFe PBA/f-CNT composite in an alkaline electrolyte greatly affects the ENRR performance. We believe that the work presented herein offers a new insight into the mechanistic aspects of the ENRR in different electrolyte systems and hence can prove very valuable for the development of effective ENRR electrode/electrolyte systems for practical applications.
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Affiliation(s)
- Aamir Y Bhat
- Department of Chemistry, Indian Institute of Technology Delhi, New Delhi - 110016, India.
| | - Priya Jain
- Department of Chemistry, Indian Institute of Technology Delhi, New Delhi - 110016, India.
| | - Mohsin A Bhat
- Department of Chemistry, University of Kashmir, Hazratbal Srinagar, 190006, India
| | - Pravin P Ingole
- Department of Chemistry, Indian Institute of Technology Delhi, New Delhi - 110016, India.
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