The production of green hydrogen requires catalysts that control the process of splitting water into oxygen and hydrogen. However, the structure of the catalyst changes under electrical tension, which also influences the catalytic activity. A team from the universities of Duisburg-Essen and Twente has investigated at BESSY II and elsewhere how the transformation of surfaces in perovskite oxide catalysts controls the activity of the oxygen evolution reaction.
In a climate-neutral energy system of the future, the sun and wind will be the main sources of electricity. Some of the “green” electricity can be used for the electrolytic splitting of water to produce “green” hydrogen. Hydrogen is an efficient energy storage medium and a valuable raw material for industry. Catalysts are used in electrolysis to accelerate the desired reaction and make the process more efficient. Different catalysts are used for hydrogen separation than for oxygen evolution, but both are necessary.
Perovskite oxide catalysts: inexpensive and with great potential
An interdisciplinary and international group of scientists from the University of Essen-Duisburg, the University of Twente, Forschungszentrum Jülich and HZB has now investigated the class of perovskite oxide catalysts for the oxygen evolution reaction in detail. Perovskite oxide catalysts have been significantly further developed in recent years, they are inexpensive and have the potential for further increases in catalytic efficiency. However, within a short time, changes appear on the surfaces of these materials which reduce the catalytic effect.
Read more on the HZB website
Image: Schematic side view of the transformed layer (light grey) on top of the perovskite film (green) grown on a substate (brown). (right) zoom-in of the side view of the transfromed layer together with spin density at the Ni sites from the density functional theory calculations.
Credit: © UDE/AG Pentcheva