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  Sajjadi, S.; Schultz, T.; Douglas-Henry, D. A.; Dharmaraj, K.; Emerenciano, A. A.; Kaplan, C.; Marks, N.; Exner, K. S.; Nicolosi, V.; Koch, N.; Browne, M. P.: Compositional Engineering of Ti₃C₂T_x MXene-NiMoO₄ Hybrid Nanostructures for Enhanced Electrocatalytic Water Oxidation. ACS Applied Energy Materials 8 (2025), p. 11313-11328

10.1021/acsaem.5c01467
Open Access Version

Abstract:
A critical step in realizing the vision of green hydrogen through water splitting is to design oxygen evolution reaction (OER) catalysts that showcase a good balance of activity and stability. This work reports the compositional tuning of a NiMoO4 material and then the subsequent varying of Ti3C2Tx MXene with the NiMoO4 hybrid nanostructures as OER catalysts in alkaline media. In this work, the optimum NiMoO4 hybrid catalyst retained good stability over 24 h of chronopotentiometry on industrial relevant supports (Ni Felt) with an overpotential value of ca. 339 mV at 100 mA cm?2. Operando Raman spectroscopy revealed that catalytically active ?-NiOOH species are formed during OER in NiMoO4 at lower overpotentials than for pure NiO and that a higher amount of the ?-NiOOH was found in the 5% MXene loading. The ICP-OES analysis showed that Mo dissolution follows a volcano trend with MXene loading (peaking at 5?wt %) before decreasing at 10?wt %. Overall, these results hold great promises for rational design strategies for MXene-supported water oxidation catalysts in alkaline electrolytes.