Interstitial carbon atoms enhance both selectivity and activity of rhodium catalysts toward C-C cleavage in direct ethanol fuel cells

Zhenming Cao; Huiqi Li; Qiyuan Fan; Zhantao Liu; Zitao Chen; Yunchao Sun; Jinyu Ye; Maofeng Cao; Cong Shen; Yaqi Jiang; Miaofang Chi; Jun Cheng; Hailong Chen; Zhaoxiong Xie; Younan Xia

doi:10.1016/j.nanoen.2023.108597

Interstitial carbon atoms enhance both selectivity and activity of rhodium catalysts toward C-C cleavage in direct ethanol fuel cells

Zhenming Cao, Huiqi Li, Qiyuan Fan, Zhantao Liu, Zitao Chen, Yunchao Sun, Jinyu Ye, Maofeng Cao, Cong Shen, Yaqi Jiang, Miaofang Chi, Jun Cheng, Hailong Chen, Zhaoxiong Xie, Younan Xia

electron Microscopy and Microanalysis

Research output: Contribution to journal › Article › peer-review

7 Scopus citations

Abstract

Selective breaking of the C-C bond in ethanol holds the key to many industrial processes, including the operation of direct ethanol fuel cells and steam reforming. Interstitial C atoms in the subsurface region of noble-metal catalysts have major impacts on the selectivity and activity, but an understanding of the mechanistic details is still elusive due to their nature of in situ formation and metastability. Herein, we develop a method to obtain stable RhC_x (x ≈ 0.5) by introducing C atoms into the interstitial sites of well-defined Rh nanosheets of 8–10 at. layers in thickness, and further elucidate the electronic and geometric effects of the interstitial C atoms on the cleavage of C-C bond. With the introduction of C atoms into half of the octahedral sites, the Rh lattice changes from a cubic to an orthorhombic structure. The lattice expansion induced by the insertion of C atoms, together with the electron transfer between C and Rh atoms, effectively suppresses the coupling reaction between OH* and CH₃CO* to form acetic acid while making the cleavage of C-C bond more exothermic. As such, we obtain a selectivity of ethanol to CO₂ as high as 18.1 %, much higher than those of the Rh counterpart (10.0 %), together with 3.1-fold improvement in kinetics. Guided by these findings, a new method is also developed to directly introduce C atoms into the subsurface of a commercial Rh black to enhance its selectivity and activity by 2.5- and 1.6- folds, respectively.

Original language	English
Article number	108597
Journal	Nano Energy
Volume	113
DOIs	https://doi.org/10.1016/j.nanoen.2023.108597
State	Published - Aug 2023

Funding

This work was supported by the National Key Research and Development Program of China (2020YFB1505802), and the Natural Science Foundation of China (No. 21931009, 21721001). Part of the research was conducted at Georgia Tech under the partial support by the start-up funds from Georgia Tech while Zhenming Cao was a visiting graduate student in the Xia Group. Hailong Chen and Zhantao Liu acknowledge the financial support from the NSF (DMR 2004878). Part of the electron microscopy analyses was performed at the Oak Ridge National Laboratory's Centre for Nanophase Materials Sciences, which is a Department of Energy, Office of Science User Facility. Use of the Advanced Photon Source at Argonne National Laboratory was supported by the U. S. DOE, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This work was supported by the National Key Research and Development Program of China ( 2020YFB1505802 ), and the Natural Science Foundation of China (No. 21931009, 21721001 ). Part of the research was conducted at Georgia Tech under the partial support by the start-up funds from Georgia Tech while Zhenming Cao was a visiting graduate student in the Xia Group . Hailong Chen and Zhantao Liu acknowledge the financial support from the NSF ( DMR 2004878 ). Part of the electron microscopy analyses was performed at the Oak Ridge National Laboratory’s Centre for Nanophase Materials Sciences, which is a Department of Energy, Office of Science User Facility. Use of the Advanced Photon Source at Argonne National Laboratory was supported by the U. S. DOE, Office of Science, Office of Basic Energy Sciences , under Contract No. DE-AC02-06CH11357 . A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory.

Funders	Funder number
Oak Ridge National Laboratory
U. S. DOE
National Science Foundation	DMR 2004878
U.S. Department of Energy
Office of Science
Basic Energy Sciences	DE-AC02-06CH11357
Oak Ridge National Laboratory
National Natural Science Foundation of China	21721001, 21931009
National Key Research and Development Program of China	2020YFB1505802

Keywords

C-C cleavage
Direct ethanol fuel cells
Interstitial carbon atom
Rhodium catalyst
Selectivity

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1016/j.nanoen.2023.108597

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title = "Interstitial carbon atoms enhance both selectivity and activity of rhodium catalysts toward C-C cleavage in direct ethanol fuel cells",

abstract = "Selective breaking of the C-C bond in ethanol holds the key to many industrial processes, including the operation of direct ethanol fuel cells and steam reforming. Interstitial C atoms in the subsurface region of noble-metal catalysts have major impacts on the selectivity and activity, but an understanding of the mechanistic details is still elusive due to their nature of in situ formation and metastability. Herein, we develop a method to obtain stable RhCx (x ≈ 0.5) by introducing C atoms into the interstitial sites of well-defined Rh nanosheets of 8–10 at. layers in thickness, and further elucidate the electronic and geometric effects of the interstitial C atoms on the cleavage of C-C bond. With the introduction of C atoms into half of the octahedral sites, the Rh lattice changes from a cubic to an orthorhombic structure. The lattice expansion induced by the insertion of C atoms, together with the electron transfer between C and Rh atoms, effectively suppresses the coupling reaction between OH* and CH3CO* to form acetic acid while making the cleavage of C-C bond more exothermic. As such, we obtain a selectivity of ethanol to CO2 as high as 18.1 %, much higher than those of the Rh counterpart (10.0 %), together with 3.1-fold improvement in kinetics. Guided by these findings, a new method is also developed to directly introduce C atoms into the subsurface of a commercial Rh black to enhance its selectivity and activity by 2.5- and 1.6- folds, respectively.",

keywords = "C-C cleavage, Direct ethanol fuel cells, Interstitial carbon atom, Rhodium catalyst, Selectivity",

author = "Zhenming Cao and Huiqi Li and Qiyuan Fan and Zhantao Liu and Zitao Chen and Yunchao Sun and Jinyu Ye and Maofeng Cao and Cong Shen and Yaqi Jiang and Miaofang Chi and Jun Cheng and Hailong Chen and Zhaoxiong Xie and Younan Xia",

note = "Publisher Copyright: {\textcopyright} 2023",

year = "2023",

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doi = "10.1016/j.nanoen.2023.108597",

language = "English",

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T1 - Interstitial carbon atoms enhance both selectivity and activity of rhodium catalysts toward C-C cleavage in direct ethanol fuel cells

AU - Cao, Zhenming

AU - Li, Huiqi

AU - Fan, Qiyuan

AU - Liu, Zhantao

AU - Chen, Zitao

AU - Sun, Yunchao

AU - Ye, Jinyu

AU - Cao, Maofeng

AU - Shen, Cong

AU - Jiang, Yaqi

AU - Chi, Miaofang

AU - Cheng, Jun

AU - Chen, Hailong

AU - Xie, Zhaoxiong

AU - Xia, Younan

PY - 2023/8

Y1 - 2023/8

N2 - Selective breaking of the C-C bond in ethanol holds the key to many industrial processes, including the operation of direct ethanol fuel cells and steam reforming. Interstitial C atoms in the subsurface region of noble-metal catalysts have major impacts on the selectivity and activity, but an understanding of the mechanistic details is still elusive due to their nature of in situ formation and metastability. Herein, we develop a method to obtain stable RhCx (x ≈ 0.5) by introducing C atoms into the interstitial sites of well-defined Rh nanosheets of 8–10 at. layers in thickness, and further elucidate the electronic and geometric effects of the interstitial C atoms on the cleavage of C-C bond. With the introduction of C atoms into half of the octahedral sites, the Rh lattice changes from a cubic to an orthorhombic structure. The lattice expansion induced by the insertion of C atoms, together with the electron transfer between C and Rh atoms, effectively suppresses the coupling reaction between OH* and CH3CO* to form acetic acid while making the cleavage of C-C bond more exothermic. As such, we obtain a selectivity of ethanol to CO2 as high as 18.1 %, much higher than those of the Rh counterpart (10.0 %), together with 3.1-fold improvement in kinetics. Guided by these findings, a new method is also developed to directly introduce C atoms into the subsurface of a commercial Rh black to enhance its selectivity and activity by 2.5- and 1.6- folds, respectively.

AB - Selective breaking of the C-C bond in ethanol holds the key to many industrial processes, including the operation of direct ethanol fuel cells and steam reforming. Interstitial C atoms in the subsurface region of noble-metal catalysts have major impacts on the selectivity and activity, but an understanding of the mechanistic details is still elusive due to their nature of in situ formation and metastability. Herein, we develop a method to obtain stable RhCx (x ≈ 0.5) by introducing C atoms into the interstitial sites of well-defined Rh nanosheets of 8–10 at. layers in thickness, and further elucidate the electronic and geometric effects of the interstitial C atoms on the cleavage of C-C bond. With the introduction of C atoms into half of the octahedral sites, the Rh lattice changes from a cubic to an orthorhombic structure. The lattice expansion induced by the insertion of C atoms, together with the electron transfer between C and Rh atoms, effectively suppresses the coupling reaction between OH* and CH3CO* to form acetic acid while making the cleavage of C-C bond more exothermic. As such, we obtain a selectivity of ethanol to CO2 as high as 18.1 %, much higher than those of the Rh counterpart (10.0 %), together with 3.1-fold improvement in kinetics. Guided by these findings, a new method is also developed to directly introduce C atoms into the subsurface of a commercial Rh black to enhance its selectivity and activity by 2.5- and 1.6- folds, respectively.

KW - C-C cleavage

KW - Direct ethanol fuel cells

KW - Interstitial carbon atom

KW - Rhodium catalyst

KW - Selectivity

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DO - 10.1016/j.nanoen.2023.108597

M3 - Article

AN - SCOPUS:85161636725

SN - 2211-2855

VL - 113

JO - Nano Energy

JF - Nano Energy

M1 - 108597

ER -

Interstitial carbon atoms enhance both selectivity and activity of rhodium catalysts toward C-C cleavage in direct ethanol fuel cells

Abstract

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Keywords

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