Modular Design of Noble‐Metal‐Free Mixed Metal Oxide Electrocatalysts for Complete Water Splitting

TLDR

Electrocatalytic water splitting into H₂ and O₂ is a key technology for carbon‑neutral energy. We report a modular materials design that yields noble‑metal‑free composite electrocatalysts with high electrical conductivity, OER and HER reactivity, and durability. The scalable bottom‑up fabrication deposits mixed‑metal‑oxide nanostructures with distinct functionalities onto copper‑foam electrodes. The composite catalyst delivers sustained OER and HER activity in 0.1 M KOH for over 10 h at low overpotentials (≈300 mV for OER, ≈100 mV for HER) with near‑100 % faradaic efficiencies, enabling multifunctional mixed‑metal‑oxide electrocatalysts for high‑performance energy conversion and storage.

Abstract

Electrocatalytic water splitting into H2 and O2 is a key technology for carbon-neutral energy. Here, we report a modular materials design leading to noble metal-free composite electrocatalysts, which combine high electrical conductivity, high OER and HER reactivity and high durability. The scalable bottom-up fabrication allows the stable deposition of mixed metal oxide nanostructures with different functionalities on copper foam electrodes. The composite catalyst shows sustained OER and HER activity in 0.1 m aqueous KOH over prolonged periods (t>10 h) at low overpotentials (OER: ≈300 mV; HER: ≈100 mV) and high faradaic efficiencies (OER: ≈100 %, HER: ≈98 %). The new synthetic concept will enable the development of multifunctional, mixed metal oxide composites as high-performance electrocatalysts for challenging energy conversion and storage reactions.