A Novel Catalyst for Aqueous Chlorate Reduction with High Activity, Salt Resistance, and Stability

Background

Both chlorate (ClO₃^-) and perchlorate (ClO₄^-) have negative effects on both human health and manufacturing process. In chlor-alkali plants (whose by-product is chlorate) the chlorate is currently remediated by either comproportionation reaction or catalytic reduction by H². Catalytic reduction of ClO3⁻ by platinum group metal catalysts and H₂ gas allows clean conversion of ClO3⁻ to innocuous Cl⁻ (the only byproduct is H₂O). However, practical applications of previously reported catalysts are challenged by:

• limited activity at ambient temperature and pressure;
• severe inhibition by concentrated salts in the brines; and,
• require high catalytic loadings to achieve a satisfactory reaction rate.

Brief Description

Inspired by biological systems, Prof. Jinyong Liu’s lab at UCR has developed a novel heterogeneous, bimetallic catalyst MoO_x-Pd/C. The catalyst contains earth-abundant molybdenum (Mo) and the carbon support of Pd/C has a high capacity to accomodate MoO_x species. The incorporation of a Mo^VI yields a highly active and robust catalyst. The porous carbon mimics the enzyme protein pocket (of microbes) to accommodate the oxygen atom transfer metal site. The representative figures shown below demonstrate the high activity and robustness of the catalyst for both chlorate and perchlorate reduction.

The effect of concentrated salts on the reduction of 1 mM ClO₃⁻ by the MoO_x-Pd/C catalyst at a loading of 0.2 g/L. The reactions were conducted at 25 ^oC and under 1 atm H₂.