Assistant Professor Adam Holewinski received a three-year, $750,000 grant from the US Department of Energy for his research, entitled "Electrochemically-assisted dehydrogenation reactions for dual-electrode hydrogen evolution." The DOE's Office of Basic Energy Sciences grant, which began in September and ends in August 2025, advances clean energy technologies and low-carbon manufacturing.
Holewinski's grant research centers on water electrolysis, which produces H2 (hydrogen)and O2 (oxygen); his research involves replacing the reaction that makes O2 with something more valuable to improve the overall value and drive down cost of H2 production. His research looks in particular at reactions that upgrade biomass-derived organics into useful chemicals, while co-producing more hydrogen as a byproduct.
Abstract
Electrochemically-Assisted Dehydrogenation Reactions for Dual-Electrode Hydrogen Evolution
Water electrolysis is a frontrunner technology for carbon-neutral hydrogen, as it can be efficiently coupled to renewable electricity. Conventional electrolysis generates H2 at the cathode of an electrochemical cell (hydrogen evolution reaction, HER), and O2 at the anode (oxygen evolution reaction, OER). Each H2 molecule generated requires passage of 2 electrons at a thermodynamic minimum potential of 1.23 V at standard conditions, with overpotential losses leading to higher applied voltages in practice. This proposal explores value-adding oxidation chemistries that can replace the OER while co-generating¬ H2 at the anode (in addition to the cathode). Despite the fact that electrolyzer anodes operate at potentials that can oxidize the hydrogen molecule, “anodic H2” can be generated if the reactant at the anode possesses hydrogen moieties with higher chemical potential than H2. This is the case for anodic valorization of several renewable organic molecules, including biomass-derived aldehydes. During (electro)oxidation of these compounds, control over chemical (pure thermally driven) vs. electrochemical steps allows for adsorbed hydrogen (H*) formed in the process to preferentially desorb from the electrode by recombination (H*+H*-->H2) rather than by discharge (H*-->H++e-), which occurs during conventional electrolysis. For aldehyde-to-acid conversion, the recombination route, labeled here “electrochemically-assisted dehydrogenation” (EAD), can generate one mole of H2 (in total, both electrodes) per mole of electrons transferred. The process is accessible with cell voltages on the order of a few hundred millivolts, lowering energy consumption significantly in comparison to standard electrolysis.
Work will center around three scientific aims. The first is to understand, at a fundamental level, the surface reactivity requirements for the established alkaline EAD of aldehydes. The composition of alloy catalyst structures will be systematically varied to establish how the electronic structure of surfaces can be altered to accelerate this process. We will then shift focus to expanding the scope of substrates—in particular, achieving EAD of alcohol functional groups. This will be facilitated by synthesis of catalysts with atomically-dispersed reactive sites that can perform dehydrogenation without cleaving C-C bonds. Finally, material constraints will be investigated for achieving EAD under conditions of high H2 pressure and low pH, more applicable to PEM electrolysis. Detailed understanding will be developed by operando spectroscopic tools coupled to rigorous kinetic measurements and computational modeling. The overarching goal is a mastery of the factors that permit and facilitate EAD to create opportunities for process intensification of water electrolysis."