Scientists develop new strategies to strengthen oxidation catalysts

The research team has developed extremely stable and efficient hydroxylation catalysts and demonstrated significant advances in the field of green water production via water separation technology.

Their research was published in Science on April 25th. The team is led by Professor Yang Ya of the Shanghai Institute of Science, China Academy of Sciences, and was led in collaboration with scientists from Huazhong University of Science and Technology, Shanghai Jiao Tong University, and Auckland University.

Water oxidation, in which water molecules are split into oxygen gas, protons and electrons, is an important half-reaction of electrolyzed water resolution. However, due to high energy consumption and slower speeds, it remains a bottleneck and requires a very efficient catalyst to overcome these barriers.

Current transition metal-based catalysts exhibit good activity due to alkali hydroxylation, but rapidly decrease under high current densities at industrial levels, primarily due to structural strain and dissolution of active metal sites under strong oxidation conditions.

To tackle this challenge, researchers proposed an innovative strategy to simultaneously balance high catalytic activity and durability under high current density at the industrial level. We built MOF@POM SuperStructure by targeting the CoFE Metal Organic Framework (MOF) on Ni-Bridged Polyoxometalate (POM).

Under hydroxylation conditions, COFE-MOF undergoes field conversion of a single layer COFE layer covalently bound to the POM unit via a Ni–O bridge into a dual hydroxide (COFE-LDH). Thus, a highly active and stable monolayer COFE hydroxide superstructure catalyst was successfully achieved.

In-situ electrochemical spectroscopy revealed a synergistic catalytic process between the active sites of Co and Fe and the Ni and W tuning centers. The valence states of catalytically active cobalt and iron gradually increase during operation, while the Ni–O and W–O tuning components undergo dynamic valence vibrations.

Systematic analysis showed that POM units play an important role in stabilizing the catalyst by regulating electron density and relieving lattice strain.

COFE-LDH@POM Catalyst demonstrated exceptional performance with alkaline electrolytes, requiring only 178 mV of radicality at 10 mA/cm2, which was able to outperform traditional transition metal-based catalysts. Integrated into an anion exchange membrane electrolyzer, the device displays a 3 A/cm2 current density at just 1.78 V cell voltage at 80°C, exceeding the US Department of Energy’s 2025 industrial target.

Long-term testing further emphasized the robustness of the system. The electrolyzer operates stably at 2 A/cm² at room temperature for over 5,140 hours, minimizing a voltage decay rate of just 0.02 mV/h. Even at high temperatures of 60°C, the system maintained continuous operation for over 2,000 hours.

This work not only sets new benchmarks for high-performance hydroxylation catalysts, but also establishes a design framework for next-generation electrocatalysts, and advances alkaline water electrolysis for industrial, high current, and low energy operations.