Sustained oxygen evolution reaction by 2D mesoporous polyoxometalate-derived composite electrocatalysts

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The electrocatalytic oxygen evolution reaction (OER) is the bottleneck for sustainable water electrolysis to access green hydrogen as a carbon-neutral energy carrier. Here, we report the modular design of a noble metal-free composite OER electrocatalyst, which features high electrical conductivity, high OER reactivity and high durability. To this end, we present a new synthetic strategy where the Keggin-type polyoxomolybdate Ni[HPMoVI 12O40] is used as the sole molecular precursor in a scalable top-down fabrication approach. This provides access to a high-performance OER composite electrocatalyst (η 10 = 320 mV) where Ni metal clusters are deposited on η-MoC/MoO2 nanocomposites anchored on electrically conductive N, P-doped mesoporous carbon. The composite catalyst shows sustained OER activity in 1 M aqueous KOH solutions over prolonged periods (t > 20 h) at a low overpotential (η = 360 mV) and high faradaic efficiency (>95%). This new synthetic concept will enable the development of multifunctional (mixed) metal carbide/oxide composites as high-performance electrocatalysts for challenging energy conversion and storage reactions.