Understanding Selectivity in the Chlorate Process: A Step towards Efficient Hydrogen Production
Artikel i vetenskaplig tidskrift, 2018

Chlorate production is a highly energy demanding industrial process, where chlorate formation is accompanied with hydrogen formation on the cathode. To ensure a high cathodic current efficiency, sodium dichromate is added to the chlorate electrolyte to avoid reduction of hypochlorite formed as a reaction intermediate in the process. However, chromate is highly toxic to humans and environment, and therefore a replacement is desired. A model system with ex situ formed chromium oxide/hydroxide films were used to study hypochlorite reduction and hydrogen evolution. The experimental results demonstrate that the hypochlorite reduction is fully blocked while hydrogen evolution readily occurs. However, in the presence of hypochlorite the hydrogen evolution reaction is inhibited. By combining experimental findings with density functional theory (DFT) calculations, the mechanism of hypochlorite reduction was revealed and the reason for inhibition by the deposited chromium(III) film was demonstrated. Based on these results possible replacements for chromate are suggested.

Density Functional Theory

Reaction mechanism

Hypochlorite reduction

Chromate

Electrocatalysis

Författare

Adriano Gomes

Akzo Nobel - Pulp and Performance Chemicals

Göteborgs universitet

Michael Busch

Chalmers, Fysik, Kemisk fysik

Mats Wildlock

Akzo Nobel - Pulp and Performance Chemicals

Nina Simic

Akzo Nobel - Pulp and Performance Chemicals

Elisabet Ahlberg

Göteborgs universitet

ChemistrySelect

2365-6549 (eISSN)

Vol. 3 23 6683-6690

Ämneskategorier

Oorganisk kemi

Materialkemi

Annan kemiteknik

DOI

10.1002/slct.201800628