Structure-Performance Relationship of LaFe1-xCoxO3 Electrocatalysts for Oxygen Evolution, Isopropanol Oxidation, and Glycerol Oxidation

Mitigating high energy costs related to sustainable H-2 production via water electrolysis is important to make this process commercially viable. Possible approaches are the investigation of low-cost, highly active oxygen evolution reaction (OER) catalysts and the exploration of alternative anode reactions, such as the electrocatalytic isopropanol oxidation reaction (iPOR) or the glycerol oxidation reaction (GOR), offering the possibility of simultaneously lowering the anodic overpotential and generating value-added products. A suitable class of catalysts are non-noble metal-based perovskites with the general formula ABO(3), featuring rare-earth metal cations at the A- and transition metals at the B-site. We synthesised a series of LaFe1-xCoxO3 materials with x=0-0.70 by automated co-precipitation at constant pH and subsequent calcination at 800 degrees C. X-ray diffraction studies revealed that the phase purity was preserved in samples with x <= 0.3. The activity towards the OER, iPOR, and GOR was investigated by rotating disk electrode voltammetry, showing a relation between structure and metal composition with the activity trends observed for the three reactions. Additionally, GOR product analysis via high-performance liquid chromatography (HPLC) was conducted after 24 and 48 h electrolysis in a circular flow-through cell setup, pointing out a trade-off between activity and selectivity.

Automated summary

Mitigating high energy costs in sustainable H-2 production via water electrolysis is crucial for commercial viability. One approach is to investigate low-cost OER catalysts and explore alternative anode reactions to reduce overpotential and generate value-added products. Non-noble metal-based perovskites, such as LaFe1-xCoxO3, show promise as catalysts with structure-activity relationships observed for OER, iPOR, and GOR reactions.