Combinatorial Development of Water Splitting Catalysts Based on the Oxygen Evolving Complex of Photosystem II

Woodbury, Neal

Arizona State University

关键词: 47 Other Instrumentation;   

DOI  :  10.2172/1080011
RP-ID  :  DE-FG36-05GO15016
RP-ID  :  FG36-05GO15016
RP-ID  :  1080011

美国|英语

来源: UNT Digital Library

【 摘 要 】

The use of methods to create large arrays of potential catalysts for the reaction H2O  ½ O2 + 2H+ on the anode of an electrolysis system were investigated. This reaction is half of the overall reaction involved in the splitting of water into hydrogen and oxygen gas. This method consisted of starting with an array of electrodes and developing patterned electrochemical approaches for creating a different, defined peptide at each position in the array. Methods were also developed for measuring the rate of reaction at each point in the array. In this way, the goal was to create and then tests many thousands of possible catalysts simultaneously. This type of approach should lead to an ability to optimize catalytic activity systematically, by iteratively designing and testing new libraries of catalysts. Optimization is important to decrease energy losses (over-potentials) associated with the water splitting reaction and thus for the generation of hydrogen. Most of the efforts in this grant period were focused on developing the chemistry and analytical methods required to create pattern peptide formation either using a photolithography approach or an electrochemical approach for dictating the positions of peptide bond formation. This involved testing a large number of different reactions and conditions. We have been able to find conditions that have allowed us to pattern peptide bond formation on both glass slides using photolithographic methods and on electrode arrays made by the company Combimatrix. Part of this effort involved generating novel approaches for performing mass spectroscopy directly from the patterned arrays. We have also been able to demonstrate the ability to measure current at each electrode due to electrolysis of water. This was performed with customized instrumentation created in collaboration with Combimatrix. In addition, several different molecular designs for peptides that bound metals (primarily Mn) were developed and synthesized and metal binding was demonstrated. Finally, we investigated a number of methods. We have shown that we can create surfaces on glass slides appropriate for patterning peptide formation and have made arrays of peptides as large as 30,000 using photolithographic methods. However, side reactions with certain amino acid additions greatly limited the utility of the photolithographic approach. In addition, we found that transferring this patterned chemistry approach to large arrays was problematic. Thus, we turned to direct electrochemical patterning using the Combimatrix electrode arrays. Here we were also able to demonstrate patterned peptide bond forming chemistry, but yield and consistency of the reaction remains insufficient to create the quality of array required for realistic optimization of catalytic peptide sequences. We are currently exploring both new polymerization chemistries for generating catalysts on surface as well as adopting methods developed at Intel for creating peptide arrays directly on electronic substrates (silicon wafers).