Promoting Alcohols Electrooxidation Coupled with Hydrogen Production via Asymmetric Pulse Potential Strategy

Abstract

Electrocatalytic organic oxidation coupled with hydrogen production emerges as a profitable solution to simultaneously reduce overall energy consumption of H2 production and synthetic high‐value chemicals. Noble metal catalysts are highly efficient electrocatalysts in oxidation reactions, but they deactivate easily weakening the benefit in actual production. Herein, we report a universal asymmetric pulse potential strategy to achieve long‐term stable operation of noble metals for various alcohol oxidation reactions and noble metal catalysts. For example, by pulsed potentials between 0.8 V and 0 V vs. RHE, palladium (Pd)‐catalyzed glycerol (GLY) electrooxidation can continuously proceed for more than 2800 h with glyceric acid (GLA) selectivity of >70%. Whereas, Pd electrocatalyst becomes nearly deactivated within 6 h of reaction under conventional potentiostatic strategy. Experimental and theoretical calculation results reveal that the generated electrophilic OH* from H2O/OH− oxidation on Pd (denoted as Pd‐OH*) acts as main active species for GLY oxidation. However, Pd‐OH* is prone to be oxidized to PdOx resulting in performance decay. When a short reduction potential (e.g., 0 V vs. RHE for 5 s) is powered, PdOx can be reversibly reduced to restore the current. Moreover, we tested the feasibility of this strategy in a flow electrolyzer, verifying the practical application potential.