TY - JOUR
T1 - Photocatalytic reduction of CO2 under supercritical CO 2 conditions
T2 - Effect of pressure, temperature, and solvent on catalytic efficiency
AU - Kawanami, Hajime
AU - Grills, David C.
AU - Ishizaka, Takayuki
AU - Chatterjee, Maya
AU - Suzuki, Akira
N1 - Funding Information:
H.K. is funded by the Japan-U.S. cooperation project for research and standardization of Clean Energy Technologies, The Ministry of Economy, Trade and Industry (METI), Japan . D.C.G. is funded under Contract DE-AC02-98-CH10886 with the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences . We thank Dr. Etsuko Fujita (Brookhaven National Laboratory) for helpful discussions. We also thank Ms. Saeko Yaeshima for her support in our experiments.
PY - 2013
Y1 - 2013
N2 - The photocatalytic reduction of CO2 to CO in single-phase, high-pressure mixtures of supercritical CO2 and N,N-dimethylformamide (DMF), using fac-ReCl(bpy)(CO)3 as a catalyst in the presence of triethanolamine as a sacrificial electron donor has been investigated. The catalytic efficiency was found to be strongly influenced by both the CO 2 and DMF concentrations. For example, the turnover number (TON) for CO formation increases linearly with CO2 pressure up to 60 at 17.8 MPa/60 C. It also increases dramatically as the [DMF] is increased from 3.8 to 6.3 M, and then remains almost constant with further increases in [DMF]. This resulted in an optimized TON of 62 at 17.8 MPa CO2/60 C and [DMF] = 6.3 M, and an initial turnover frequency (TOF) of ∼56 h-1 at 17.8 MPa CO2/60 C and [DMF] = 11.4 M. These values are 5× and 2.3× higher, respectively than those obtained under biphasic low-pressure conditions (0.1 MPa CO2), demonstrating that significant improvements in catalytic performance are possible through the use of high concentrations of CO2. Manipulation of the incident light intensity led to further improvements in both TON (up to 72 under low light levels) and TOF (up to 117 h-1 under the highest light level investigated).
AB - The photocatalytic reduction of CO2 to CO in single-phase, high-pressure mixtures of supercritical CO2 and N,N-dimethylformamide (DMF), using fac-ReCl(bpy)(CO)3 as a catalyst in the presence of triethanolamine as a sacrificial electron donor has been investigated. The catalytic efficiency was found to be strongly influenced by both the CO 2 and DMF concentrations. For example, the turnover number (TON) for CO formation increases linearly with CO2 pressure up to 60 at 17.8 MPa/60 C. It also increases dramatically as the [DMF] is increased from 3.8 to 6.3 M, and then remains almost constant with further increases in [DMF]. This resulted in an optimized TON of 62 at 17.8 MPa CO2/60 C and [DMF] = 6.3 M, and an initial turnover frequency (TOF) of ∼56 h-1 at 17.8 MPa CO2/60 C and [DMF] = 11.4 M. These values are 5× and 2.3× higher, respectively than those obtained under biphasic low-pressure conditions (0.1 MPa CO2), demonstrating that significant improvements in catalytic performance are possible through the use of high concentrations of CO2. Manipulation of the incident light intensity led to further improvements in both TON (up to 72 under low light levels) and TOF (up to 117 h-1 under the highest light level investigated).
KW - Rhenium catalyst
KW - Turnover frequency
KW - Turnover number
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U2 - 10.1016/j.jcou.2013.07.008
DO - 10.1016/j.jcou.2013.07.008
M3 - Article
AN - SCOPUS:84889086923
VL - 3-4
SP - 93
EP - 97
JO - Journal of CO2 Utilization
JF - Journal of CO2 Utilization
SN - 2212-9820
ER -