Immobilization of iridium nanoparticles on an ITO substrate for selective transformation of glycerol to 1,3-dihydroxyacetone and process tracking

Abstract

Glycerol (Gly) is a major by-product of biodiesel production, and its conversion to high-value-added chemicals under mild conditions holds significant economic benefits. This study demonstrated that efficient and selective conversion of Gly to 1,3-dihydroxyacetone (DHA) can be achieved with a yield of 87% by using immobilized iridium nanoparticles (IrNPs) as the nanozyme catalyst. An IrNPs-ITO plate was prepared by electrodeposition of Ir³⁺ on ITO. As-prepared IrNPs-ITO exhibited excellent peroxidase-like (POD-like) activity, showing a K_m for H₂O₂ as low as 0.45 mM and a v_max of 1.02 × 10⁻⁴ mM s⁻¹. The IrNPs-ITO also exhibited remarkable durability, retaining about 90% of its original activity after 15 successive cycles. Furthermore, an in situ monitoring method was developed to track the Gly oxidation process based on the impedance changes caused by the specific adsorption of Gly onto the IrNPs-ITO electrode. Hence, the immobilization of IrNPs not only effectively suppresses their aggregation and facilitates recovery and reuse of the nanozyme but also provides a methodological foundation for real-time monitoring of the reaction processes.