Paper Mill Waste Becomes a Catalyst for Green Hydrogen

Turning Paper Mill Waste Into Hydrogen Catalysts

The key to green hydrogen production becoming a cornerstone of our economy is to make it cheap enough to compete with fossil fuels or other artificial liquid fuels.

The process also needs to be as sustainable as possible, as replacing fossil fuel pollution with another type of pollution would be counterproductive.

A lack of investment and infrastructure has also been a problem, something that megaprojects like the European Hydrogen Backbone (EHB) should solve.

Still, the main problem of hydrogen production is its catalysts. For a long time, hydrogen electrolysis relied on expensive catalysts using platinum or palladium. As these metals are very rare and expensive (as we explained in “Investing In Platinum – The Universal Catalyst”), the hydrogen electrolyzers are also very expensive.

Luckily, a series of alternatives are emerging, for example, nanorods of nickel, iron nanoscopic hollow balls, silicon carbide for photocatalysis, or cobalt tungsten oxide.

A new option that might be even more sustainable has been proposed by researchers at the Shenyang Agricultural University and Guangdong University of Technology (China), using waste products of paper production as a catalyst.

They published their findings in Biochar, under the title “Lignin-derived carbon fibers loaded with NiO/Fe3O4 to promote oxygen evolution reaction”.

Oxygen Evolution For Hydrogen Production

Water, being made of oxygen and hydrogen atoms (H₂O), needs to have the oxygen atoms turned into atmospheric oxygen to produce usable hydrogen (H₂).

This step is usually one of the hardest to engineer so that it happens efficiently and does not waste electrical power. It is also where expensive catalysts are required.

Instead of using these catalysts, the researchers used lignin, a component of wood and a byproduct leftover from the refining of wood pulp into paper. The process extracts cellulose, leaving behind the unwanted lignin.

Annual production of lignin exceeds 70 million tons. Currently, it is often simply burned for energy, despite producing little power, merely to dispose of it.

“Oxygen evolution is one of the biggest barriers to efficient hydrogen production.

Our work shows that a catalyst made from lignin, a low-value byproduct of the paper and biorefinery industries, can deliver high activity and exceptional durability. This provides a greener and more economical route to large-scale hydrogen generation.”

— Yanlin Qin, Guangdong University of Technology

Making Lignin Into A Hydrogen Catalyst

Carbon Fibers As Catalysts

In general, carbon scaffolds are considered ideal as catalysts because of their high surface area, tailorable porosity, chemical inertness, and excellent electrical conductivity.

But other materials like polyacrylonitrile fibers or CVD-grown carbon fibers are of limited use due to high costs, expensive manufacturing, or insufficient chemical characteristics.

The researchers took the unwanted lignin and realized that its aromatic-rich structure and complex microscopic structure make it a promising carbon precursor for the fabrication of high-performance porous carbon materials.

Lignin’s disordered microtexture can anchor ultrafine metal/metal-oxide nanoparticles. In addition, its interconnected fiber network offers straight electronic highways and open macroporous channels for electric current to flow in. Lastly, lignin’s life-cycle carbon footprint production is estimated to be < 0.5 kg CO₂ eq kg^–1, more than 10x lower than other carbon-based materials proposed so far.

Producing Lignin Catalysts

Lignin, polyacrylonitrile (PAN), and metal precursors (Ni²⁺, Fe³⁺) were co-dissolved in N,N-dimethylformamide (DMF) and processed via electrospinning to form uniform precursor fibers.

It was later carbonized to form the final lignin-derived carbon fibers with metal catalysts uniformly embedded into the fiber.

The resulting material was analyzed under transmission electron microscopy, revealing the NiO/Fe₃O₄ nanoparticles anchored onto the lignin-derived carbon fibers.

A nanoscale junction between NiO and Fe₃O₄ was also observed, and is expected to facilitate electron transfer and boost oxygen evolution reaction activity.

Further analysis using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy reveals the structural composition of the catalyst, finding the best conditions for the formation of the NiO and Fe₃O₄ junction.

Measuring Catalysis Performance

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The oxygen evolution reaction activity was then measured and compared to NiO and Fe₃O₄ material when separated.

It demonstrated that the chemical reactions for hydrogen production are strongest when both metallic catalysts are present. It also demonstrated the long-term stability of the catalyst, with more than 50 hours of continuous operation showing no significant damage to the catalyst.

The scientists then delved deeper, trying to understand exactly what reactions are occurring, proving that the reaction follows a process known as an “adsorption-evolution mechanism (AEM) pathway”, with successive absorption of electrons and temporary charged forms of oxygen, individual atoms, and molecules.

Applications

The usage of very cheap lignin, iron, and somewhat cheap nickel, to create a high-efficiency, low-cost, long-durability hydrogen catalyst is opening the path to two things at once:

• Valorization of lignin, a carbon by-product that is, for now, burned, making it into a green energy catalyst instead.
• The possibility of mass production of a hydrogen catalyst with a method that can be quickly scaled.

As all the methods and materials used in this study are easy to scale, this could be the first alternative catalyst material for hydrogen production that not only does not use rare metals of the platinum group, but also can be immediately deployed at scale for mass production.

Further studies will be needed to assess the very long-term stability of the modified lignin (>1 year of continuous or irregular use) in real-life conditions, with changes in moisture, temperature, UV light, etc, needing to be assessed for its viability as an industrial-scale hydrogen catalyst.

Investing in Hydrogen Production

Plug Power Inc.

Plug Power is a leader in green hydrogen, with a focus on fuel cells. The company reports 72,000+ fuel cells installed across 300+ locations, with a large footprint in material-handling fleets. In particular, its fuel cells power over 40,000 forklifts, with revenues up x8 since 2013.

It is also active in building hydrogen infrastructure, like hydrogen production, logistics, utility-scale power generation, and deliveries.

The company is aiming for scale to reduce hydrogen production costs from $10/kg to $4/kg, while multiplying production by 14x in 2027. It should also replace all the externally sourced hydrogen, which was often resold to customers at a loss.

Due to the massive investments to increase production capacity 19x since 2020, the company is not profitable yet, but progress in sourcing its own hydrogen should change that.

The company sees its solutions as either a direct mobility fuel or a complement to EVs, as hydrogen allows for the reduction of the pressure on the grid during EVs’ peak charging time, which does not match the periods of production of renewables during the day.

As a major producer of fuel cells, Plug Power would greatly benefit from a shift toward a hydrogen-based economy. A cheaper fuel cell catalyst could be integrated into its designs, and boost the adoption rate of hydrogen vehicles and grid-scale energy storage.

So this makes Plug Power a good stock to bet on a turn toward hydrogen in general, with a growth in demand for its fuel cells each time a cheaper method to produce, store, transport, or utilize hydrogen is invented.

(You can read more about Plug Power in our dedicated investment report on the company.)

Latest Plug Power (PLUG) Stock News and Developments

Study Referenced

^{1. Xuezhi Zeng, Yutao Pan, Yi Qi, Yanlin Qin, & Xueqing Qiu. Lignin-derived carbon fibers loaded with NiO/Fe3O4 to promote oxygen evolution reaction. BiocharX. 1, Article number: e011. 27 November 2025. https://www.maxapress.com/article/doi/10.48130/bchax-0025-0011}