Abstract
Proton transfer is critically important to many electrocatalytic reactions, and directed proton delivery could open new avenues for the design of electrocatalysts. However, although this approach has been successful in molecular electrocatalysis, proton transfer has not received the same attention in heterogeneous electrocatalyst design. Here, we report that a metal oxide proton relay can be built within heterogeneous electrocatalyst architectures and improves the kinetics of electrochemical hydrogen evolution and oxidation reactions. The volcano-type relationship between activity enhancement and pKa of amine additives confirms this improvement; we observe maximum rate enhancement when the pKa of a proton relay matches the pH of the electrolyte solution. Density-functional-theory-based reactivity studies reveal a decreased proton transfer energy barrier with a metal oxide proton relay. These findings demonstrate the possibility of controlling the proton delivery and enhancing the reaction kinetics by tuning the chemical properties and structures at heterogeneous interfaces.
| Original language | English |
|---|---|
| Pages (from-to) | 26016-26027 |
| Number of pages | 12 |
| Journal | Journal of the American Chemical Society |
| Volume | 145 |
| Issue number | 48 |
| DOIs | |
| State | Published - Dec 6 2023 |
| Externally published | Yes |
Funding
The authors would like to acknowledge financial support from Chemical Transformation Initiative, a Laboratory Directed Research and Development Project at Pacific Northwest National Laboratory (PNNL) for materials synthesis, the US Department of Energy (DOE) Hydrogen and Fuel Cell Technology Office (Program Manager: Katie Randolph) for materials characterization and mechanisms study, and the US DOE Basic Energy Sciences, Chemical Sciences, Geosciences and Biosciences Division, Catalysis Program (FWP 47319) for DFT calculation study. The STEM and XPS measurements were performed at the William R. Wiley Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the U.S. Department of Energy’s Office of Biological and Environmental Research and located at PNNL. The computer resources were provided by the National Energy Research Center (NERSC) located at the Lawrence Berkeley National Laboratory (LBNL) and the PNNL Research Computing facility. PNNL is operated by Battelle for DOE under Contract DE-AC05-76RL01830. The authors thank Andrew T Pitman for language editing.
