Superhydrophilic Self-supported Perovskite Oxides for Oxygen Evolution Reactions in Oilfield Wastewater

Abstract

Developing highly efficient catalysts for oxygen evolution reactions (OER) in complex water environments is crucial for promoting the photovoltaic electrolysis of water splitting for hydrogen production in arid areas. However, traditional catalysts often exhibit limitations in terms of reaction kinetics and electrode corrosion resistance. In this work, we successfully prepared a self-supporting perovskite complex oxide La_0.7Sr_0.3CoO_3-δ/NF (LSC/NF) catalyst by means of simple hydrothermal synthesis combined with programmed annealing, and successfully applied to OER reaction in oilfield wastewater. In alkaline oilfield wastewater, at a current density of 10 mA cm⁻², LSC/NF requires only 411 mV of overpotential, which is lower than that of LSC (493 mV) and traditional catalyst RuO₂ (451 mV), suggesting a high OER catalytic activity. The good electrocatalytic activity can be attributed to its superhydrophilicity, increased electrochemical active surface area, faster reaction kinetics and higher oxygen vacancy concentration. This research offers valuable new insights for the development of OER electrocatalysts with high catalytic activity in complex water systems in arid areas.

Graphical Abstract

A self-supporting perovskite oxide catalyst La_0.7Sr_0.3CoO_3-δ/NF was synthesized by a simple process combining hydrothermal and annealing. The growth of perovskite oxide nanosheets directly on the conductive nickel foam matrix gives the catalyst a strong hydrophilicity and significantly expands its electrochemical active surface area, thus enhancing the OER activity of LSC/NF in oilfield wastewater.