Abstract
Metallic silver (Ag) is known as an efficient electrocatalyst for the conversion of carbon dioxide (CO2) to carbon monoxide (CO) in aqueous or nonaqueous electrolytes. However, polycrystalline silver electrocatalysts require significant overpotentials in order to achieve high selectivity toward CO2 reduction, as compared to the side reaction of hydrogen evolution. Here we report a high-surface-area Ag nanocoral catalyst, fabricated by an oxidation-reduction method in the presence of chloride anions in an aqueous medium, for the electro-reduction of CO2 to CO with a current efficiency of 95% at the low overpotential of 0.37 V and the current density of 2 mA cm-2. A lower limit of TOF of 0.4 s-1 and TON > 8.8 × 104 (over 72 h) was estimated for the Ag nanocoral catalyst at an overpotential of 0.49 V. The Ag nanocoral catalyst demonstrated a 32-fold enhancement in surface-area-normalized activity, at an overpotential of 0.49 V, as compared to Ag foil. We found that, in addition to the effect on nanomorphology, the adsorbed chloride anions play a critical role in the observed enhanced activity and selectivity of the Ag nanocoral electrocatalyst toward CO2 reduction. Synchrotron X-ray photoelectron spectroscopy (XPS) studies along with a series of control experiments suggest that the chloride anions, remaining adsorbed on the catalyst surface under electrocatalytic conditions, can effectively inhibit the side reaction of hydrogen evolution and enhance the catalytic performance for CO2 reduction.
| Original language | English |
|---|---|
| Pages (from-to) | 5349-5356 |
| Number of pages | 8 |
| Journal | ACS Catalysis |
| Volume | 5 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - Jul 30 2015 |
Fingerprint
Keywords
- carbon dioxide reduction
- chloride modification
- electrocatalysis
- high selectivity
- nanoporous Ag
ASJC Scopus subject areas
- Catalysis
Cite this
Effect of Chloride Anions on the Synthesis and Enhanced Catalytic Activity of Silver Nanocoral Electrodes for CO2 Electroreduction. / Hsieh, Yu Chi; Senanayake, Sanjaya D.; Zhang, Yu; Xu, Wenqian; Polyansky, Dmitry.
In: ACS Catalysis, Vol. 5, No. 9, 30.07.2015, p. 5349-5356.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effect of Chloride Anions on the Synthesis and Enhanced Catalytic Activity of Silver Nanocoral Electrodes for CO2 Electroreduction
AU - Hsieh, Yu Chi
AU - Senanayake, Sanjaya D.
AU - Zhang, Yu
AU - Xu, Wenqian
AU - Polyansky, Dmitry
PY - 2015/7/30
Y1 - 2015/7/30
N2 - Metallic silver (Ag) is known as an efficient electrocatalyst for the conversion of carbon dioxide (CO2) to carbon monoxide (CO) in aqueous or nonaqueous electrolytes. However, polycrystalline silver electrocatalysts require significant overpotentials in order to achieve high selectivity toward CO2 reduction, as compared to the side reaction of hydrogen evolution. Here we report a high-surface-area Ag nanocoral catalyst, fabricated by an oxidation-reduction method in the presence of chloride anions in an aqueous medium, for the electro-reduction of CO2 to CO with a current efficiency of 95% at the low overpotential of 0.37 V and the current density of 2 mA cm-2. A lower limit of TOF of 0.4 s-1 and TON > 8.8 × 104 (over 72 h) was estimated for the Ag nanocoral catalyst at an overpotential of 0.49 V. The Ag nanocoral catalyst demonstrated a 32-fold enhancement in surface-area-normalized activity, at an overpotential of 0.49 V, as compared to Ag foil. We found that, in addition to the effect on nanomorphology, the adsorbed chloride anions play a critical role in the observed enhanced activity and selectivity of the Ag nanocoral electrocatalyst toward CO2 reduction. Synchrotron X-ray photoelectron spectroscopy (XPS) studies along with a series of control experiments suggest that the chloride anions, remaining adsorbed on the catalyst surface under electrocatalytic conditions, can effectively inhibit the side reaction of hydrogen evolution and enhance the catalytic performance for CO2 reduction.
AB - Metallic silver (Ag) is known as an efficient electrocatalyst for the conversion of carbon dioxide (CO2) to carbon monoxide (CO) in aqueous or nonaqueous electrolytes. However, polycrystalline silver electrocatalysts require significant overpotentials in order to achieve high selectivity toward CO2 reduction, as compared to the side reaction of hydrogen evolution. Here we report a high-surface-area Ag nanocoral catalyst, fabricated by an oxidation-reduction method in the presence of chloride anions in an aqueous medium, for the electro-reduction of CO2 to CO with a current efficiency of 95% at the low overpotential of 0.37 V and the current density of 2 mA cm-2. A lower limit of TOF of 0.4 s-1 and TON > 8.8 × 104 (over 72 h) was estimated for the Ag nanocoral catalyst at an overpotential of 0.49 V. The Ag nanocoral catalyst demonstrated a 32-fold enhancement in surface-area-normalized activity, at an overpotential of 0.49 V, as compared to Ag foil. We found that, in addition to the effect on nanomorphology, the adsorbed chloride anions play a critical role in the observed enhanced activity and selectivity of the Ag nanocoral electrocatalyst toward CO2 reduction. Synchrotron X-ray photoelectron spectroscopy (XPS) studies along with a series of control experiments suggest that the chloride anions, remaining adsorbed on the catalyst surface under electrocatalytic conditions, can effectively inhibit the side reaction of hydrogen evolution and enhance the catalytic performance for CO2 reduction.
KW - carbon dioxide reduction
KW - chloride modification
KW - electrocatalysis
KW - high selectivity
KW - nanoporous Ag
UR - http://www.scopus.com/inward/record.url?scp=84941137345&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84941137345&partnerID=8YFLogxK
U2 - 10.1021/acscatal.5b01235
DO - 10.1021/acscatal.5b01235
M3 - Article
AN - SCOPUS:84941137345
VL - 5
SP - 5349
EP - 5356
JO - ACS Catalysis
JF - ACS Catalysis
SN - 2155-5435
IS - 9
ER -