Pérez Viramontes, Nicté; Collins Martínez, Virginia; Escalante García, Ismailia Leilani; Flores Hernández, José; Galván Valencia, Marisol; Durón Torres, Sergio Miguel
Resumen:
Mixed oxide Ir-Sn-Sb-O electrocatalyst was synthesized using thermal decomposition
from chloride precursors in ethanol. Our previous results showed that Ir-Sn-Sb-O possesses
electrocatalytic activity for an oxygen evolution reaction (OER) in acidic media. In the present
work, the physicochemical characterization and performance of Ir-Sn-Sb-O in an electrolysis cell
are reported. IrO2 supported on antimony doped tin oxide (ATO) was also considered in this study
as a reference catalyst. Scanning electron microscopy (SEM) images indicated that Ir-Sn-Sb-O
has a mixed morphology with nanometric size. Energy dispersive X-ray spectroscopy (EDS)
showed a heterogeneous atomic distribution. Transmission electron microscopy (TEM) analysis
resulted in particle sizes of IrO2 and ATO between 3 to >10 nm, while the Ir-Sn-Sb-O catalyst
presented non-uniform particle sizes from 3 to 50 nm. X-ray diffraction (XRD) measurements
indicated that synthesized mixed oxide consists of IrO2, IrOx, doped SnO2 phases and metallic Ir.
The Ir-Sn-Sb-O mixed composition was corroborated by temperature programmed reduction (TPR)
measurements. The performance of Ir-Sn-Sb-O in a single cell electrolyser showed better results for
hydrogen production than IrO2/ATO using a mechanical mixture. Ir-Sn-Sb-O demonstrated an onset
potential for water electrolysis close to 1.45 V on Ir-Sn-Sb-O and a current density near to 260 mA
mg−1 at 1.8 V. The results suggest that the mixed oxide Ir-Sn-Sb-O has favorable properties for further
applications in water electrolysers.