課題番号 ：S-17-KU-0065
利用形態 ：機器利用
利用課題名（日本語） ：CO2電気化学還元用白金電極触媒の開発
Program Title (English) ：Development of the Pt electrocatalyst for CO2 electrochemical reduction
利用者名（日本語） ：Paul J.A. Kenis
Username (English) ：Paul J.A. Kenis
所属名（日本語） ：University of Illinois
Affiliation (English) ：University of Illinois

１．概要（Summary ）
Cost effective electroreduction of CO2 to CO requires the development of electrochemical systems that exhibit high activity (partial current density (jCO) >150 mA cm-2) at low cell overpotentials (|ηcell| <1 V). However, achieving such benchmarks remain difficult. In this work, Au-based electrocatalyst loaded on multi-walled carbon nanotube (MWNT/PyPBI/Au) was used to aim low overpotential for electrochemical reduction of CO2. ２．実験（Experimental） The electrodes were prepared using a filtration method. The SWNT (0.8 mg) was dissolved in DMAc (3 mL), then sonicated for 1 h using a bath-type sonicator (Branson 5510). The obtained solution was then slowly casted on an SUS mesh (SUS316, 100 mesh). After washing with methanol, the electrode was dried under vacuum at 160 oC. No binder was used during the electrode fabrication processes. ３．結果と考察（Results and Discussion） In the CO2 Capture and Utilization (CCU), demonstration of a highly efficient electrochemical CO2 conversion system (electrolyzer), driven by renewable energy, and able to produce value-added chemicals (i.e., fuels or their intermediates) is the scope of the research. Through the interdisciplinary research between two divisions, highly active electroreduction of CO2 to CO at low overpotentials was realized. Specifically, the electrochemical system exhibits an onset cell potential of just −1.50 V, an onset cathode potential of just −0.04 V vs RHE, and jCO as high as 99 and 158 mA cm−2 at corresponding energetic efficiencies for CO of 63.8 and 49.4%, respectively, which exceeded our Roadmap target of energy efficiency > 60%.

Fig. 1 Preparation scheme, TEM image of MWNT/PyPBI/Au and CO2 electrochemical reduction profile.
４．その他・特記事項（Others）
The authors gratefully acknowledge technical support from the Ms. Yuriko Kakita for the preparation of CNT sheets.
５．論文・学会発表（Publication/Presentation）
(1) S. Verma, Y. Hamasaki, C-R. Kim, W. Huang, S. Lu, H-R. Molly Jhong, A. A. Gewirth, T. Fujigaya, N. Nakashima, P. J. A. Kenis, Insights into the Low Overpotential Electroreduction of CO2 to CO on a Supported Gold Catalyst in an Alkaline Flow Electrolyzer, ACS Energy Letters, 3, 193-198, 2018

６．関連特許（Patent）
No patent was obtained.