Boosting Hydrogen Production by Selective Anodic Electrooxidation of Ethanol over Trimetallic PdSbBi Nanoparticles: Composition Matters

The conventional hydrogen evolution from water electrolysis is severely impeded by the sluggish kinetics of oxygen evolution reaction (OER). In this work, an integrated electrolysis system of replacing the anodic OER with a thermodynamically favorable ethanol oxidation reaction (EOR) has been developed by using PdSbBi/C as an electrocatalyst. To maximize the EOR performance, the composition of PdSbBi nanoparticles is tuned by varying the ratio of Sb and Bi precursors. Ternary PdSbBi-based electrocatalysts exhibit enhanced activity and stability toward EOR compared to commercial Pd/C and binary catalysts. In particular, the Pd76Sb17Bi7/C catalyst delivers a very high specific activity up to 52.4 mA cm(-2) and mass activity of 2.66 A mg(Pd)(-1). Besides, this EOR process is demonstrated to have high selectivity with acetic acid as the oxidation product in the electrolyte. When coupled with a cathodic platinum mash, the two-electrode electrolyzer cell requires a voltage input of merely 0.61 V to afford a current density of 10 mA cm(-2). Density functional theory calculations reveal that the presence of Sb and Bi can promote the adsorption of hydroxide ions and facilitate the removal of reaction intermediates in the EOR pathway. This work provides a novel catalyst for the energy-efficient coproduction of acetic acid and hydrogen fuel.

Automated summary

In this study, an integrated electrolysis system was developed using PdSbBi/C as an electrocatalyst to replace the sluggish oxygen evolution reaction (OER) in water electrolysis with a thermodynamically favorable ethanol oxidation reaction (EOR), resulting in efficient energy production and coproduction of acetic acid. It was found that tuning the composition of PdSbBi nanoparticles significantly enhanced the activity and stability of the EOR process.