FuelCellsWorks

Chemists in Germany have taken a leaf out of nature’s book to develop a new, low-cost, iron-based catalyst powered by light that can extract hydrogen from formic acid. 

Formic acid is one of the major products formed during biomass processing, and has been widely investigated as a stable and readily available carrier for hydrogen, which could subsequently be used in fuel cells. However, pulling the hydrogen out of the formate relies on expensive catalysts based on noble metals. The new catalyst is based on inexpensive iron, and as it can be driven by sunlight does not require fossil fuels to provide energy to activate it.

In nature, iron-based hydrogenase enzymes are highly efficient at producing hydrogen. The iron centres within the enzyme are stabilised by coordinating groups within the surrounding protein. The team from the University of Rostock, led by Mathias Beller and Ralf Ludwig, created their catalytic system by screening a large number of organometallic compounds in the presence of various ligands to stabilise the iron centre – akin to an enzyme – that would decompose formic acid into hydrogen and carbon dioxide. 

The best catalyst system identified was triirondodecacarbonyl [Fe₃(CO)₁₂] in the presence of triphenylphosphine, 2,2′:6′2”-terpyridine and dimethylformamide.

These ingredients form a catalyst in situ, which is activated by visible light. ‘We do not know all the details of exactly how the system works,’ Ludwig says. ‘The ligands are stabilising the catalyst, enabling it to run for longer – if they were not there the iron would drop out of the system.’

When the system is exposed to visible light in the presence of formic acid, hydrogen and CO₂ are produced; when the light is switched off, the reaction stops.  

‘This means we can use sunlight to release hydrogen so we do not need conventional energy such as from fossil fuels,’ says Ludwig, adding that it should now be possible to experiment with modifying the iron compound and the ligands to produce a more efficient catalyst that is activated by optimal wavelengths of light. 

Justin Hargreaves, a catalyst expert at the University of Glasgow in the UK, says that the work represents a ’significant advance’ in the search for new, non-noble catalysts for hydrogen generation from formic acid, and ‘will stimulate further activity in this area.’ 

Edman Tsang, of the University of Oxford, who has investigated the feasibility of a ‘formic acid economy’ says, ‘Although only a moderate catalyst turnover number is obtained at present, the inexpensive and convenient combination of iron complex and ligands with simple switching on and off the light source have moved the technology a step forward towards applications.’ In terms of practical applications, Tsang suggests the next challenges will be to address catalyst separation issues and move away from the use of organic solvents and excess additive. 

Simon Hadlington 

Dr. David Dixon

TUSCALOOSA, Ala. — A University of Alabama researcher whose work could lead to more affordable hydrogen-powered vehicles on the roadways has been recognized for his contribution to the overall efforts of the U.S. Department of Energy’s Center of Excellence in Chemical Hydrogen Storage.  

Dr. David Dixon, professor and Robert Ramsay Chair in UA’s department of chemistry, received a 2010 Hydrogen Program Research and Development Award for Outstanding Contributions to Hydrogen Storage Technologies earlier this month at the Center’s Annual Review Award Lunch in Washington, D.C.  

The award recognizes Dixon’s work in computational chemistry in support of chemical hydrogen storage technologies under development by the Center.  

His research has predicted reliable thermodynamics for thousands of compounds for hydrogen release and spent fuel regeneration, factors that could dramatically reduce the time and efforts required to design and develop new materials.  

Dixon’s team at UA included Daniel Grant and Edward Garner, graduate students; Dr. Myrna Matus, a post-doctoral fellow; Minh Nguyen, a visiting professor, and Darryl J. Outlaw, Kevin Anderson, J. Pierce Robinson and Jacob Batson, undergraduate students.  

The Chemical Hydrogen Storage Center of Excellence is a collaboration among multiple university and industrial partners across the country, including The University of Alabama, and with the Los Alamos National Laboratory in New Mexico and Pacific Northwest National Laboratory in Washington.  

UA’s department of chemistry is part of the College of Arts and Sciences, the University’s largest division and the largest liberal arts college in the state. Students from the College have won numerous national awards including Rhodes Scholarships, Goldwater Scholarships and memberships on the USA Today Academic All American Team.

The European Commission Fuel Cells and Hydrogen Joint Undertaking has announced its 2010 Call for Proposals that outlines how funding will be distributed towards research, technological development and demonstration projects.

A whopping €89.1million will be made available across four areas: transportation and refuelling; storage and distribution; hydrogen production; and stationary power generation and CHP.

Among the specific topics outlined in the 2010 announcement are:

- Transportation and refuelling infrastructure - €36.1million will be dedicated for a large-scale demonstration of second generation fuel cell vehicles and of a refuelling infrastructure that will expand on the existing demo sites across Europe. Other activities will include research and development into membrane electrode assemblies of polymer electrolyte membrane fuel cells in the hope of reducing platinum loading; and investigating degradation phenomena particularly relating to transport applications.

- Hydrogen production and distribution – There will be a focus on research and development in an effort to improve reforming technologies for hydrogen production. A total of €11million will be dedicated to addressing mid-term fuelling requirements based on conventional and alternative fuels.

- Stationary power generation – Around €33million will go towards material development to improve performance of fuel cell stacks and balance of plants components. Money will also be invested into research for novel architectures for cells and stack design; while the improvement of fuel cell system components will also be looked at.

- Early markets – A further €11.5million of funding will go towards the demonstration of the readiness of fuel cell systems applied to materials handling vehicles. The aim is to stimulate the market for these applications.

- Cross cutting – Finally, €2million will focus on two topics – the development of a comprehensive technology monitoring and assessment framework; and the development of financing models for reusable or recyclable components of hydrogen and fuel cell technologies.