A Protocol for Electrocatalyst Stability Evaluation: H₂O₂ Electrosynthesis for Industrial Wastewater Treatment

Abstract

Electrocatalysis has been proposed as a versatile technology for wastewater treatment and reuse. While enormous attention has been centered on material synthesis and design, the practicality of such catalyst materials remains clouded by a lack of both stability assessment protocols and understanding of deactivation mechanisms. In this study, we develop a protocol to identify the wastewater constituents most detrimental to electrocatalyst performance in a timely manner and elucidate the underlying phenomena behind these losses. Synthesized catalysts are electrochemically investigated in various electrolytes based on real industrial effluent characteristics and methodically subjected to a sequence of chronopotentiometric stability tests, in which each stage presents harsher operating conditions. To showcase, oxidized carbon black is chosen as a model catalyst for the electrosynthesis of H2O2, a precursor for advanced oxidation processes. Results illustrate severe losses in catalyst activity and/or selectivity upon the introduction of metal pollutants, namely magnesium and zinc. The insights garnered from this protocol serve to translate lab-scale electrocatalyst developments into practical technologies for industrial water treatment purposes.

Pulsed Electrolysis of Boron-Doped Carbon Dramatically Improves Impurity Tolerance and Longevity of H2O2 Production

“…We evaluated the viability of each catalyst in wastewater using a conventional H-cell with RDE and RRDE assemblies (Figure S5) and a custom electrolyte of Na 2 SO 4 + NaCl (50 mM each, pH 7), termed the baseline (BL) matrix throughout this study (Figure S6). This electrolyte was selected to emphasize Cl – and SO 4 2– as the two dominant species in real industrial effluents. , Relatively low catalyst mass loadings (0.05 mg cm –2 ) were utilized across all experiments to prevent operation at full conversion, which may mask deactivation kinetics . The ORR voltammograms, double-layer capacitance, and H 2 O 2 molar fraction selectivity measurements are presented in Figure S7.…”

Enhanced Degradation of Diclofenac by Electro-Activated Permanganate: A Critical Role of In Situ Formed H2O2

“…Electrochemical technologies have attracted growing attention due to their easy operation, low chemical agent inputs, and satisfactory adaptability. 14,15 Particularly, electrochemical processes have been applied in combination with various chemical oxidants such as ozone, persulfates, and chlorine for water decontamination, where highly reactive species (e.g., hydroxyl radical (HO•), sulfate radical (SO 4…”

Hierarchical N-Doped Co/Carbon Heterostructures with Tunable Selectivity for H2O2 Production from Air

“…Nowadays, some pioneering works use traditional gas diffusion electrodes that contain a catalyst coated with a superhydrophobic PTFE layer to maintain the stability of the catalyst, even at the expense of the ORR activity. − However, carbon-based materials as a support, especially hierarchical porous structures with abundant desirable macropores and high surface areas and conductivities, have gained interest as 2e – ORR electrocatalysts. − By adjusting the surface wettability, they remarkably boost H 2 O 2 production via enhancing the mass transport of the reaction gas …”