New insights on efficient electrochemical production of hydrogen peroxide

Published: 16 June 2025| Version 1 | DOI: 10.17632/mdx24hbs8h.1
Contributors:
Robson Rocha, Manuel Andres Rodrigo, Beatriz Nogueira, Robson Souto, Marcos Lanza

Description

Hydrogen peroxide production using a very efficient 3-D printed electrochemical reactor (height 4 cm and width 4 cm) equipped with a gas diffusion electrode was evaluated within a wide current density range, close to the necessary for industrial production. The system obtained outstanding efficiencies, which were found to depend on the electrolyte composition but not on the current density. It reached 100% when sodium sulfate was the salt contained in the electrolyte. Opposite to what was expected, efficiencies decreased notably when perchlorate and nitrate were used instead of sulfate in the electrolyte, pointing out the existence of catalytic effects associated with mediated oxidation mechanisms. This evidence pointed out the significance of the anodic process in the cathodic production of hydrogen peroxide and let us obtain a simple phenomenological model that sheds light on the mechanisms that primarily affect the efficient production of hydrogen peroxide and obtain recommendations about how the process efficiency can be increased, making the technology more competitive which takes up very little space at 4 cm high and 4 cm wide and with respect to other electrochemical technologies and facing promisingly the industrial anthraquinone process.

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Experimental setup. Tests were conducted in a small lab-scale plant consisting of an electrochemical reactor (height 4 cm and width 4 cm) manufactured in resin using 3-D printing technology (stereolithography) sized to host electrodes of 1.6 cm2, one power supply Minipa model MPC-3005, two peristaltic pumps Intlab model BT-100 and electrolyte reservoir tank of 1 L. The electrochemical reactor used in this work is a proprietary design of the E3L lab described elsewhere. It was equipped with MMO anodes DSA-Cl2 (exposed area of 1.6 cm2) and with a GDE (exposed area of 1.6 cm2) manufactured with carbon synthesized using sugarcane bagasse, where the material and electrode were characterized by Sperandio et al (2025)[31]. A cationic membrane Nafion 112 was used to evaluate performance of the reactor in a two compartments configuration. In tests made with the one compartment reactors, only one of the two hydraulic circuits were used. Analytical methods. During the electrolysis, the H2O2 was quantified (mg L-1) using titanium (IV) oxysulfate solution as an indicator reagent using UV-Vis spectroscopy (at λ = 408 nm, UV–vis 1700 Spectrophotometer from Shimadzu), according literature [30]. Experimental procedure. All tests were replicated in triplicate using three reactors’ prototypes with the same configuration to check not only reproducibility but also robustness of the results obtained with the reactors. Results shown are the average of the three replications. Current densities in the range 25 to 150 mA cm-2 and tests were carried out in discontinuous operation mode by recirculating the electrolyte between the tank and the reactor at 30 L h-1 using 50 mM sodium sulphate (pH 3 and conductivity 9.8 mS cm-1) or 13 mM sodium nitrate (pH 3 and conductivity 9.8 mS cm-1) or 10 mM sodium perchlorate (pH 3 and conductivity 9.8 mS cm-1). The GDE was fed with a flowrate of oxygen 99.9% with a flowrate of 60 mL min-1. In several tests, oxygen was substituted by nitrogen 99.9% to gain insights about the role of the anode processes. The linear sweep voltammetry experiments were performed in an Autolab model PGSTAT 302N using the same system presented in Figure 1, with Pt//Ag/AgCl as a reference system, according to Beati et al. (2012)[32], and DSA-Cl2 as a counter electrode.

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Categories

Hydrogen Peroxide, Electrochemical Reactor Theory

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