Energy conversion challenges in solar-driven photoelectrochemical water splitting and carbon dioxide reduction
Event details
| Date | 07.09.2016 |
| Hour | 16:00 |
| Speaker | Prof. Joel W. Ager, University of California, Berkeley |
| Location | |
| Category | Conferences - Seminars |
Solar to fuel conversion, if it could be performed in a sustainable manner, could provide an alternative to mankind’s currently unsustainable use of fossil fuels. Solar fuel generation by photoelectrochemical (PEC) methods is a potentially promising approach to address this fundamental and important challenge.
Experimental demonstrations of PEC systems which convert solar energy to hydrogen via water splitting and to carbon-based fuels via CO2 reduction date back to the 1970s. However, an approach which could be practical and scalable has not yet been developed. The key research bottlenecks that need to be addressed before practical and scalable solar fuel devices become a reality will be outlined. The analysis will focus on a fundamental requirement of any sustainable solar conversion technology, which is to generate more energy over its useful lifetime than was required to manufacture and maintain it (positive return on energy investment).
Reported laboratory solar to hydrogen (STH) conversion efficiencies range from <1% to over 20%, with a number of approaches that yield efficiencies comparable to solar PV. However, there are very few reports of long term operational stability, which is a clear prerequisite for a positive energy return on investment. The long term stability of protective coatings for water oxidation photoanodes will be discussed, with an emphasis on the experimental procedures required to predict the operational lifetime.
Electrochemical CO2 reduction is comparatively less mature as a technology and hence the challenges are more basic. While there has been considerable recent progress in lowering overpotentials for CO2 reduction via nanostructuring of heterogeneous catalysts, most of these systems produce two- electron reduction products (CO or formate), both of which will require further processing to be used as a fuel. Indeed, there are very few report of systems which produce products other than CO or formate with high selectivity. Recently, we have found that the activity of Cu nanoparticles for methane production can be greatly enhanced when supported on sp2-based carbon materials. Moreover, building on work performed with Cu nanocubes, we have designed Cu nanostructures which achieve up to 70% conversion of CO2 to C2+ products.
Bio: Joel W. Ager III is a Staff Scientist in the Materials Sciences Division of Lawrence Berkeley National Laboratory and an Adjunct Professor in the Materials Science and Engineering Department, UC Berkeley. He is a Principal Investigator in the Electronic Materials Program and in the Joint Center for Artificial Photosynthesis (JCAP) and is Associate Program Leader of the Singapore Berkeley Initiative for Sustainable Energy (SinBeRISE). He graduated from Harvard College in 1982 with an A.B in Chemistry and from the University of Colorado in 1986 with a PhD in Chemical Physics. After a post-doctoral fellowship at the University of Heidelberg, he joined Lawrence Berkeley National Laboratory in 1989. His research interests include the fundamental electronic, optical, and transport characteristics of photovoltaic materials, development of new photoelectrodes and electrocatalysts for solar fuels production, and the development of new oxide and sulfide based transparent conductors. Professor Ager is a frequent invited speaker at international conferences and has published over 290 papers in refereed journals. His work is highly cited, with over 21,000 citations and an h-index of 70.
Experimental demonstrations of PEC systems which convert solar energy to hydrogen via water splitting and to carbon-based fuels via CO2 reduction date back to the 1970s. However, an approach which could be practical and scalable has not yet been developed. The key research bottlenecks that need to be addressed before practical and scalable solar fuel devices become a reality will be outlined. The analysis will focus on a fundamental requirement of any sustainable solar conversion technology, which is to generate more energy over its useful lifetime than was required to manufacture and maintain it (positive return on energy investment).
Reported laboratory solar to hydrogen (STH) conversion efficiencies range from <1% to over 20%, with a number of approaches that yield efficiencies comparable to solar PV. However, there are very few reports of long term operational stability, which is a clear prerequisite for a positive energy return on investment. The long term stability of protective coatings for water oxidation photoanodes will be discussed, with an emphasis on the experimental procedures required to predict the operational lifetime.
Electrochemical CO2 reduction is comparatively less mature as a technology and hence the challenges are more basic. While there has been considerable recent progress in lowering overpotentials for CO2 reduction via nanostructuring of heterogeneous catalysts, most of these systems produce two- electron reduction products (CO or formate), both of which will require further processing to be used as a fuel. Indeed, there are very few report of systems which produce products other than CO or formate with high selectivity. Recently, we have found that the activity of Cu nanoparticles for methane production can be greatly enhanced when supported on sp2-based carbon materials. Moreover, building on work performed with Cu nanocubes, we have designed Cu nanostructures which achieve up to 70% conversion of CO2 to C2+ products.
Bio: Joel W. Ager III is a Staff Scientist in the Materials Sciences Division of Lawrence Berkeley National Laboratory and an Adjunct Professor in the Materials Science and Engineering Department, UC Berkeley. He is a Principal Investigator in the Electronic Materials Program and in the Joint Center for Artificial Photosynthesis (JCAP) and is Associate Program Leader of the Singapore Berkeley Initiative for Sustainable Energy (SinBeRISE). He graduated from Harvard College in 1982 with an A.B in Chemistry and from the University of Colorado in 1986 with a PhD in Chemical Physics. After a post-doctoral fellowship at the University of Heidelberg, he joined Lawrence Berkeley National Laboratory in 1989. His research interests include the fundamental electronic, optical, and transport characteristics of photovoltaic materials, development of new photoelectrodes and electrocatalysts for solar fuels production, and the development of new oxide and sulfide based transparent conductors. Professor Ager is a frequent invited speaker at international conferences and has published over 290 papers in refereed journals. His work is highly cited, with over 21,000 citations and an h-index of 70.
Practical information
- General public
- Free
Organizer
- Buonsanti Raffaella <[email protected]>
Contact
- Buonsanti Raffaella <[email protected]>