Photoelectrocatalytic Hydrogen Production

The products of photosynthetic processes such as photocatalysis and CO₂ reduction are motivating technological developments in artificial photosynthesis. If properly replicated, such photosynthetic processes could be used to efficiently and sustainably produce highly desirable fuels and chemicals such as hydrogen.

Photoelectrocatalysis and electrolysis

Photoelectrocatalytic processes offer the potential to use solar energy to split water into oxygen and hydrogen at low operating temperatures and with very high efficiency. While electrolysis technologies are rapidly advancing to produce green hydrogen, the large energy demand and operating costs are still limiting its viability. Investing into the research of photoelectrocatalytic hydrogen production therefore has the potential to provide an additional way to obtain green hydrogen — without the need for electrolysis

Photoelectrocatalytic hydrogen research and projects

A range of compounds are under investigation as potential catalysts to facilitate photoelectrocatalytic hydrogen generation. Many techniques utilize TiO₂ based photocatalysts for such processes. As an example, one research group in China is using TiO₂ nanotube arrays in conjunction with semiconducting nanoparticles to act as a water splitting catalyst to form H₂.

The oil company Repsol is also keen to find more efficient means of green hydrogen production. As the largest producer and consumer of hydrogen in Spain, they’ve worked on several photoelectrocatalytic hydrogen plants, including a recent project at the Petronor complex in Basque Country. They had previously collaborated with Spanish research institutes and Enagás to fulfill both onshore and offshore electrolysis projects in Mallorca and Asturias.

Challenges with the scalability of photoelectrocatalytic hydrogen production

Process efficiency

Due to the high energy requirements and the multi-electron transfer mechanism involved in water splitting, it is challenging to produce hydrogen with high efficiency — so researchers are getting creative. In 2020, Shinshu University developed an aluminum-doped SrTiO₃ catalyst system which is nearly 100% efficient under very specific light and semiconductor conditions. This process will require optimization to become truly viable, but it is a significant step towards achieving efficient photocatalytic water splitting. A second study in 2021 found biomass can be used as the source of hydrogen to increase yields up to 70%.

But the challenge remains to find a practical photocatalyst that can be formed from earth-abundant materials, doesn’t make toxic waste products, and is able to efficiently capture and convert solar energy. With that in mind, yet another study is experimenting with the use of charred wood as a substrate to increase the efficiency of the water splitting reaction. For now, though, photoelectrochemical solar-to-hydrogen conversion remains below 20% efficiency for practical, non-lab based systems.

Water source

Another challenge is finding a viable water source for photoelectrocatalytic hydrogen processes as they scale, as it is unlikely that high-purity, fresh water can be used as a reactant. Some researchers are examining the possibility of splitting sea water, although this requires specialized compounds. The use of Co₃O₄ is currently under investigation, as it is a stable, non-toxic, porous film that can act as a catalyst with the sea water. For now, hydrogen produced using this method only has 8% efficiency.

Photobiological hydrogen production

Trying to mimic the role of photosystem II, composed of 17 protein subunits and numerous cofactors, is proving to be quite a challenge. Therefore researchers are also investigating alternatives, such as the use of microalgae which exhibit natural photolytic and photofermentive hydrogen production. Hydrogen yield via this method is still low, but researchers are investigating how to improve efficiency and are finding creative ways to fuel their processes such as with wastewater.

Conclusion

Like many aspects of the hydrogen economy, the study of photoelectrocatalytic hydrogen production is still in its infancy and has quite a way to go before it is commercially viable. With time and continued interest, this research will hopefully provide solutions to current climate and technical challenges faced around the world.

Enabling Liquid Hydrogen Fuel Systems in Maritime Innovation

Alicat MCRQ Mass Flow Controllers Support TU Delft Hydro Motion Team’s Hydrogen Boat for the Monaco Energy Boat Challenge

Jun 12, 2025 | Hydrogen

Empowering Discovery on Water

The transition to sustainable energy in the maritime sector demands more than ambition, it requires precision. That is why Alicat Scientific is proud to support the TU Delft Hydro Motion Team as a Bronze Partner in their groundbreaking 2025 campaign: to design, build, test and race Mira, a liquid hydrogen-powered boat at the Monaco Energy Boat Challenge.

Equipping this innovative project with our MCRQ mass flow controllers enables the team to manage hydrogen fuel delivery safely and accurately, helping them prove that liquid hydrogen can power the next generation of clean marine propulsion.

Figure 1: Mira at the official reveal. Hydro Motion Team’s 2025 liquid hydrogen-powered boat.

The Challenge: Making Hydrogen Work for Maritime Transport

The goal of the TU Delft Hydro Motion Team is as ambitious as it is inspiring: to design, build, test, and race a fully functioning boat powered by liquid hydrogen, all within one year, and to compete at the Monaco Energy Boat Challenge 2025. But beyond the competition itself, the team’s mission reaches further. By proving that a boat can operate successfully on liquid hydrogen, they aim to spark broader innovation across the maritime sector and demonstrate hydrogen’s potential as a clean, scalable alternative to fossil fuels.

This project builds on the team’s past successes with compressed hydrogen, already a proven, zero-emission marine fuel. But as the team pushes for longer range and greater onboard efficiency, storage volume and energy density become the next major challenges. To solve this, the team chose to work with liquid hydrogen. With a volumetric energy density three times higher than compressed hydrogen at 350 bar, liquid hydrogen offers a powerful solution for saving space and extending endurance, key requirements in performance vessels.

But storing and using liquid hydrogen introduces challenges. The fuel must be kept at -253°C, requiring insulated cryogenic tanks. The team addresses this with a custom double-walled, vacuum-insulated carbon-fibber tank system, limiting heat ingress to just 7 watts, equivalent to a small LED bulb. To avoid wasting energy, waste heat from the fuel cell is used to bring hydrogen up to the required ~20°C operating temperature before reaching the fuel cell.

These trade-offs (boil-off rates, tank volume, storage weight, and onboard vaporization) are exactly the kinds of real-world constraints this project is designed to explore. And while Mira is a compact, foiling boat, the broader engineering question remains: could a system like this scale to larger vessels, such as ferries? That is the kind of thinking Alicat is excited to support with partners who are pushing the boundaries of what is possible.

The Role of Alicat: Flow Control After Vaporization

In Mira’s hydrogen system, hydrogen is stored as a cryogenic liquid. Before reaching the fuel cell, it passes through a vaporizer, transitioning into gas at ambient temperature. This phase is critical: delivering gas at the right pressure and flow requires stable regulation, fast feedback, and precise control.

Figure 2: Simplified diagram of the Hydro Motion Team’s hydrogen system.

To meet this need, the team integrated the Alicat MCRQ mass flow controller immediately downstream of the vaporizer. This device manages the mass flow of hydrogen gas into the fuel cell and enables:

Delivers stable and precise feed pressure to the fuel cell.
Measures hydrogen consumption through real-time mass flow monitoring
Monitors pressure and temperature to help prevent fuel cell issues like dehydration or fuel starvation.
Supports test validation and real-world performance optimization.

Compact, ATEX Zone 2 certified, and designed for fast system response, the MCRQ integrates easily into the tight constraints of a race-ready vessel. Its role is vital during system development, helping the team collect data, tune parameters, and prepare for race-day performance. In short, it helps translate bold hydrogen engineering into operational reliability.

Figure 3: Alicat’s MCRQ unit mounted inside the Hydro Motion Team’s hydrogen control system.

Why the MCRQ Was Selected

The Hydro Motion Team, together with our application engineers, selected the Alicat MCRQ series for its proven capability in low-flow hydrogen gas applications, offering a powerful combination of precision, speed, and safety. Key features that influenced the decision include:

Flow range of 0–1.5 g/s, which translates to ±0.01 g/s uncertainty at a nominal 1 g/s flow, small enough to maintain consistent fuel cell output.
4–20 mA analog output, chosen specifically for its high-speed update rates (kHz range)
ATEX Zone 2 IIC certification, requiring minimal additional safety infrastructure.
Upstream valve position, enabling precise regulation of downstream feed pressure, supporting target values like the ~2.5 bar commonly seen in fuel cell stacks.
±1.0% accuracy of reading (or ±0.2% of full scale)

Together, these features provide the team with a robust, compact, and responsive solution, a key enabler of real-world testing and a step toward scalable, clean hydrogen propulsion.

Competition Progress and What Comes Next

The TU Delft team unveiled the boat, Mira, earlier this year and is now deep into the testing phase, preparing for the Monaco Energy Boat Challenge 2025.

As testing progresses, the team continues optimizing the integration between hydrogen storage, vaporization, and control systems. Alicat’s instrumentation plays a central role in capturing this performance data for analysis and refinement.

This partnership represents more than a technical contribution. It reflects our belief that sustainable innovation thrives where education, engineering, and real-world experimentation meet.

By supporting the Hydro Motion Team and their work on Mira, Alicat contributes to:

Advancing liquid hydrogen fuel systems in marine transport
Empowering hands-on engineering education
Promoting practical low-emission propulsion technologies

We are honoured to be part of this project and proud to know that our instruments are helping to steer the future of clean maritime energy.

Together, we are not just measuring hydrogen. We are helping to Fuel the Future.

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