ZnO As an Active and Selective Catalyst for Electrochemical Water Oxidation to Hydrogen Peroxide

Electrochemical synthesis of hydrogen peroxide (H₂O₂) via two-electron water oxidation reaction (2e-WOR) is an ideal process for delocalized production for water cleaning and other applications. Previously reported water oxidation catalysts have limited activity and selectivity, imposing a bottleneck for broad adoption of this technology. We identify ZnO as a new stable, nontoxic, active, and selective catalyst for 2e-WOR to generate H₂O₂. Using density functional theory calculations, we propose that the (1010) facet of ZnO is an effective catalyst for 2e-WOR and confirm the prediction experimentally. We synthesize ZnO nanoparticles with a high fraction of (1010) facets and find that this catalyst gives an overpotential of 40 mV at 0.1 mA/cm² and peak Faradaic efficiency of 81% toward H₂O₂ evolution.

Acknowlegment: This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Science, via Grant DE-SC0008685 to the SUNCAT Center of Interface Science and Catalysis. X.Z. thanks the generous support of the Stanford Woods Institute for the Environment and the Stanford Natural Gas Initiative.