Low-Voltage Electrolytic Hydrogen Production Derived from Efficient Water and Ethanol Oxidation on Fluorine-Modified FeOOH Anode

Abstract

Highly active, earth-abundant anode catalysts are urgently required for the development of electrolytic devices for hydrogen generation. However, the reaction efficiencies of most developed electrocatalysts have been intrinsically limited due to their insufficient adsorption of reactants leading to high energy intermediates. Here, we establish that electronegative fluorine can moderate the binding energy between the Fe sites (FeOOH) and reactants (OH– or C2H5O–), resulting in more optimized adsorption, and can enhance the positive charge densities on the Fe sites to facilitate oxygen evolution reaction (OER) and ethanol oxidation. Consequently, a low electrolytic voltage (1.43 V to achieve 10 mA cm–2) for H2 production was obtained by integrating the efficiently anodic behaviors of OER and ethanol oxidation. The results reported herein point to fluorine moderation as a promising pathway for developing optimal electrocatalysts and contribute to ongoing efforts of mimicking water splitting.