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| Type |
Oral Presentation |
| Area |
Current Trends in Environmental and Energy Chemistry |
| Room No. |
407호 |
| Time |
THU 10:00-: |
| Code |
ENVR.O-5 |
| Subject |
Highly Selective and Efficient Photoelectrochemical CO2 reduction by Nanoporous Au on Si Photoelectrode |
| Authors |
송준태, 오지훈1,*
KAIST 나노융합연구소, Korea
1KAIST EEWS, Korea
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| Abstract |
Photoelectrochemical (PEC) CO2 reduction reaction (CO2RR) has been intensively focused as a promising technology for producing fuel. Up to date, however, poor CO2RR catalysts performance is an obstacle to obtain efficienct PEC cell.
We present a Si photoelectrode decorated with a nanoporous Au thin film to achieve highly efficient and selective PEC CO2RR. It includes two important issues as follows.
(1) Fabrication of nanoporous Au thin film for co-catalysts
We successfully developed nanoporous Au on thin film structure by sequent electrochemical process (anodization & reduction reaction). This developed electrochemical treatment forms induces 20 nm thick nanoporous Au layers on plarnar Au surface. The nanoporous Au layer is observed to compose of a lot of nanoparticles with grain boundaries. For CO2RR performance, dramatically improved CO2 reduction catalytic activity is obtained for CO generation (remarkable selectivity and lowered overpotential) as compared to bare Au thin film. It is very significant that our 20 nm thick nanoporous Au layer shows very exceptional CO2RR activity.
(2) Novel design of Si photoelectrode with nanoporous Au thin film
To combine the successfully developed nanoporous Au thin film on Si photoelectrode, a novel Si photoelectrode design was proposed by adopting a mesh-type pattering of nanoporous Au thin film. Mesh-type patterned Au thin film is independently wired for electrochemical treatment and the back of the photoelectrode is utilized for Ohmic contact. As the result, our Si photoelectrode decorated by the nanoporous Au thin film exhibits 91% Faradiac efficiency of CO production at -0.03V (vs RHE). We note that this potential is more positive than even CO redox potential (-0.11V (vs RHE). These results should be originated from the superior CO2RR property of the nanoporous Au thin film and generated high photovoltage inside Si substrate.
To the best knowledge, it is first time to report high CO2 reduction selectivity (over 90%) at more positive potential than equilibrium potential. Furthemore, our work provides a general platform of an efficient PEC CO2 conversion cell with adopting various efficient co-catalysts regardless of substrate. |
| E-mail |
sjunkun87@kaist.ac.kr |
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119th General Meeting of the KCS