Electrochemical Synthesis of Thin Films for Use as Water and Biofuel Electrocatalysts
In creating a society focused on responsible energy production and consumption, green chemistry is now at the forefront of much scientific research. Interest in renewable energy and alternative fuels is by no means new but with the rapidly depleting fossil fuel resources, and hazardous byproducts of its production and use the areas hold the most promising answers to the looming energy crisis. Suitable catalyst materials for electrochemical water reduction and biomass conversion, specifically 5-hydroxymethylfurfural (HMF) reduction, have been previously identified. In the case of water electrolysis, precious metal catalysts are excellent due to the low energy input, however they are not economically feasible. With respect to HMF reduction, current methods of chemical reduction require harsh conditions that make its use unappealing. In this work, these drawbacks are tackled in several ways. First by using electrochemical synthesis to provide a tunable method for the construction of electrocatalyst electrodes. Many parameters that affect surface morphology, film composition and electrical connectivity including electrolyte composition, potential applied, and temperature are readily controlled. Second by using more suitable materials such as the non-precious metal catalyst material MoS2, recently identified as an excellent catalyst for the hydrogen evolution reaction (HER). A new deposition procedure was used to create a nanoporous molybdenum sulfide morphology. This material was chemically different than MoS2 but provided a more catalytic surface to investigate the promoter ion effect of transition metal ions on HER catalyst surfaces. After-deposition modification of the nanoporous film’s active surface using Pt and Co lowered the overpotential necessary for the HER. Third, using electrochemical reduction as an alternative to the established chemical reduction of HMF has many of the same advantages as with electrochemical synthesis. A major benefit is the electrochemical generation of hydrogen necessary for HMF reduction. Our study focused on comparing the efficiencies of electrodeposited Cu-based electrodes to commercial Cu metal foil.
Choi, Purdue University.
Alternative Energy|Chemistry|Materials science
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