Understanding the Role of Varying Ti3C2Tx MXene in Ni/Ti3C2Tx for the Oxygen Evolution Reaction

The current state-of-the-art catalysts for the oxygen evolution reaction (OER) in an anion exchange membrane (AEM) electrolyser are not efficient enough to surpass green H-2 produced by other electrolyser technologies, such as Proton Exchange Membrane (PEM) electrolysers. One reason for this is due to the AEM catalysts not being active enough and lacking long-term stability. In this work, we combine Ni based material with Ti3C2Tx MXene at different loadings (1, 5 and 10 %) to understand the effect of the MXene on the OER activity and stability. Our results show that the amount of MXene not only affects the OER performance, but the materials surface is also altered. Interestingly, the Ti3C2Tx is still present in the bulk for all composites but the surface of the composites contains different amounts of oxidized Ti3C2Tx i.e. TiO2. The optimum material in this study for the OER is the NiOx/1 %Ti3C2Tx which can be rationalized by the lower Ti/Ni ratio in the starting materials hence producing less overall surface TiO2 during OER. Additionally, when the pure NiOx and the 1 % Ni-Ti3C2Tx are compared by operando Raman spectroscopy, the NiOx/1 %Ti3C2Tx exhibits beta-NiOOH at lower overpotentials, which is known to be present for efficient OER on Ni materials.