New catalyst improves clean hydrogen production to 99.9% efficiency

Hydrogen carries about 120 megajoules of energy per kilogram, roughly triple the punch of gasoline. Yet producing it without carbon emissions still hinges on squeezing every last electron through water.

Global electrolyzer capacity doubled to 1.4 gigawatts in 2023, but the International Energy Agency says the world needs 560 gigawatts by 2030 to meet net‑zero goals.

That gap keeps chemists awake at night. Heng Liu of Tohoku University just gave them a reason to sleep better. His team reports a cobalt–molybdenum catalyst that turns nearly every electron into hydrogen.

Precatalysts set the stage

Many industrial catalysts begin life as a precatalyst that reshapes under voltage. That makeover, called reconstruction, can raise or wreck performance.

“It’s hard to design a catalyst that works well when that catalyst itself can change,” explained Liu, noting the challenge of hitting a moving target. His group decided to steer the change rather than fight it.

When an electrode drives electrolysis, water molecules split into hydrogen and oxygen. The half‑reaction that releases hydrogen is the hydrogen evolution reaction.

During that reaction Liu’s cobalt‑rich Co2Mo3O8 precursor sheds molybdenum into the liquid. The exposed cobalt atoms then bind hydroxide ions and reorganize into a nanoscale shell of Co(OH)₂.

Cobalt and clean hydrogen

Cobalt holds a sweet spot on the periodic table when it comes to catalytic activity. It has just the right balance of electron density to attract and release protons during hydrogen production.

When combined with molybdenum, the alloy forms a conductive and stable surface that resists corrosion in alkaline solutions. That durability is essential for keeping large-scale electrolysis running without constant maintenance.

Voltage control lets the shell wrap the crystal core evenly, creating a tidy heterostructure. Laboratory tests show the interface speeds the step in which water donates its first proton.

Meanwhile the dissolved molybdate anions drift back and perch on the shell. At slightly more negative potentials they pair up as Mo₂O₇²⁻, loosening hydrogen’s grip and letting bubbles escape faster.

Molybdate ions and clean hydrogen

The presence of MoO₄²⁻ (molybdate anion) and Mo₂O₇²⁻ ions isn’t just a side effect of the reconstruction process, it plays a direct role in performance.

These ions alter the way hydrogen sticks to and leaves the surface, which is key to keeping the reaction fast and efficient.

When Mo₂O₇²⁻ forms under slightly more negative voltage, it encourages weaker hydrogen binding. This makes it easier for hydrogen atoms to pair up and detach as gas, rather than staying stuck on the surface.

Faradaic efficiency measures what fraction of current produces the desired product. The new catalyst reaches 99.9 percent at –0.4 volts versus the reversible hydrogen electrode, with a hydrogen output of 1.85 moles per hour.

Those numbers hold for more than a month at about 100 milli‑amps per square centimeter, a current density relevant to alkaline industrial cells.

Commercial platinum‑on‑carbon electrodes in the same test lost three‑quarters of their activity within a day.

From lab bench to factory floor

The study showed the material keeps working after sitting on the shelf for weeks. That stability lowers shipping and storage costs for large‑scale projects.

Cobalt and molybdenum are already mined for batteries and steel, so supply chains exist. Even so, recycling plans will be needed to prevent price spikes if demand climbs sharply.

Analysts expect the hydrogen‑electrolyzer market to jump from $1.75 billion in 2025 to $40 billion by 2032, a 56 percent annual growth rate. Near‑perfect catalysts like Liu’s could help those projections stick.

Difficulty of clean hydrogen scaling

Scale‑up still faces hurdles such as heat management and electrode fouling. The Tohoku group plans pilot studies that pair their catalyst with intermittent wind power on Japan’s Pacific coast.

A separate challenge lies in sourcing alkaline electrolytes at the volumes gigawatt systems demand. Recycling potassium hydroxide and capturing stray molybdenum will be part of the engineering brief.

Researchers outside the project welcome the mechanistic insights. By tracking both the solid surface and the changing liquid, the team underscored that chemistry never happens in isolation.

Every efficiency gain cuts electricity bills, the biggest cost in green hydrogen. That is why a single decimal point (99.9 instead of 99.0) echoes far beyond the laboratory.

Changing hydrogen infrastructure

If scaled successfully, this catalyst could lower the cost of producing hydrogen by cutting energy waste and extending equipment life.

That kind of savings makes on-site hydrogen generation more practical for industries like shipping, steelmaking, and fertilizer.

It also opens the door for smaller, distributed electrolyzer units that could plug directly into local solar or wind farms.

More localized production would mean less reliance on pipelines or cryogenic transport, simplifying the hydrogen supply chain.

The study is published in Nature Communications.

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