Bifunctional Strontium Cobalt Molybdenum Oxide (Sr2CoMoO6) Perovskite as an Efficient Catalyst for Electrochemical Water Splitting Reactions in Alkaline Media

Developing earth-abundant low-cost electrocatalysts is of prime research interest towards the need for clean energy technology, such as water-splitting reactions. Herein, we have explored the electrocatalytic activity of the double perovskite-based strontium cobalt molybdenum oxide (SCMO) towards water-splitting reactions, both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), in harsh alkaline condition (1 M KOH). Prepared by scalable autocombustion synthesis, the as-synthesised bulk SCMO perovskite exhibited impressive electrocatalytic performance attributed to its substantial electrochemical active surface area, measured at 26.3 cm(2). For the OER, it exhibited an overpotential of 350 mV with a Tafel slope value of 76 mV/dec. Concurrently, it showed proficient activity in the HER, revealing an overpotential of 270 mV and a Tafel slope of 112 mV/dec. Further, this perovskite material was stable during continuous electrocatalysis over a 24 h period in harsh alkaline media with a negligible increase in observed overpotential value. The electronic density of states confirmed that the Co plays a pivotal role in enhancing electrocatalytic activities. This is achieved by a substantial reduction in the band gap and enhancement of the d-band centre to an optimal level, rendering the system more favourable for electrocatalytic reactions. Our study contributes essential insights to the advancement of the design and utilization of perovskite-based catalysts in the realm of sustainable energy technologies.