Titanium PTL for PEM Electrolyzers: How to Choose One

To choose a titanium porous transport layer for a PEM electrolyzer, balance two things that pull against each other: close contact with the anode catalyst layer, and open pores that let oxygen bubbles escape. Research shows that thinner, more porous titanium PTLs tend to perform better at high current, but too little titanium at the interface weakens contact. This guide turns those findings into a practical choice for your test cell.

It is written for researchers and engineers building PEM water electrolyzer test cells, including those moving over from PEM fuel cell work. Researchers at Lawrence Berkeley National Laboratory describe the PTL as a key component that is still one of the least explored in the cell, largely because few structures have been available to test.

What does a titanium PTL do in a PEM electrolyzer?

The PTL sits between the anode catalyst layer and the flow field. It has to let water reach the catalyst, let oxygen gas leave, carry electrons, and support the catalyst layer and membrane under compression. Every design choice, from structure to thickness, shifts the balance between these jobs.

Titanium PTL structures you will see

Structure	How it is made	What to check before buying
Sintered powder	Titanium powder pressed and sintered into a porous plate	Particle size, porosity, thickness, surface flatness
Felt / fibre	Titanium fibres laid down and sintered	Fibre diameter, porosity, how the surface meets the catalyst layer
Mesh or expanded metal	Woven or expanded titanium sheet	Opening size; often used behind a finer layer
Tape-cast (research)	Titanium slurry with poreformers cast into sheets, then sintered	Mostly lab-made today; pore size set by poreformer

 

Supplier data sheets vary in what they report. Ask for thickness, porosity and pore size at minimum, and photos of the surface that will face the catalyst layer.

Titanium porous transport layer for a PEM electrolyzer: thickness and porosity

A 2025 study at Istanbul Technical University compared titanium PTLs of different thickness and porosity, including PTLs thinned by rolling. Thinner PTLs performed better, especially at high current densities, and gave higher overall efficiency. Higher porosity improved gas removal and reactant transport.

For a test cell, that points to starting with the thinnest PTL your hardware can support mechanically, with good porosity. Very thin PTLs can deform under compression, so check that your cell design spreads the load evenly.

Contact with the catalyst layer vs bubble removal

The interface between PTL and catalyst layer is where the trade-off is sharpest. In a 2023 study, Berkeley Lab researchers made titanium PTLs by tape casting, a low-cost and scalable method, and controlled the pores with PMMA poreformer beads. More titanium improved contact with the catalyst layer but caused severe mass-transport losses from gas bubbles. Adding large poreformer beads created a highly porous structure that removed gas well while staying mechanically sound.

Their best PTL, with a 60:40 titanium-to-PMMA ratio and 60 µm beads, outperformed a standard commercial titanium powder PTL by 62 mV at 4 A/cm², according to the Berkeley Lab publication. The lesson for buyers: a dense, flat surface helps contact, but the bulk of the PTL must stay open enough to clear oxygen.

What about carbon GDLs from fuel cell work?

Fuel cell researchers often ask whether the carbon paper or GDL they already stock can go on the electrolyzer anode. The PEM electrolyzer studies cited in this guide all use titanium PTLs on the anode side. Before using carbon on the anode, ask your supplier or the literature for evidence that it survives your operating conditions. For carbon materials on the fuel cell side, see our overview of membranes, catalysts and GDLs for fuel cell research.

Selection checklist for your test cell

• Confirm the active area and the space your cell hardware allows for the PTL.
• Choose a structure (sintered powder or felt for most test cells).
• Start thin, if your hardware supports it mechanically.
• Ask for porosity, pore size and thickness data, plus a surface photo.
• Check flatness: uneven surfaces cause poor contact and local hot spots.
• Keep compression the same across every PTL you compare.
• Record cell voltage at fixed current densities, so differences can be compared fairly.
• Test at least two PTLs side by side rather than relying on one result.

Our range of fuel cell experimental materials includes materials for PEM electrolyzer and fuel cell test cells. Results always depend on your hardware, catalyst layer and compression, so no PTL choice is right for every cell. This guide was prepared by Canrd’s materials team.

Frequently asked questions

Why are PEM electrolyzer PTLs usually made of titanium?

The PEM electrolyzer studies cited here all use titanium PTLs on the anode side. They carry water in, oxygen out and electrons through the cell while supporting the catalyst layer. Ask your supplier for corrosion and stability data for your operating conditions.

Is a thinner PTL better?

Often, yes. A 2025 Istanbul Technical University study found thinner titanium PTLs performed better, especially at high current density, with higher overall efficiency. Very thin PTLs can deform under compression, though, so match thickness to what your cell hardware can support evenly.

How porous should a titanium PTL be?

Porous enough to clear oxygen bubbles, while keeping good contact with the catalyst layer. Research shows higher porosity improves gas removal, but too little titanium at the interface weakens contact. Compare at least two porosities in your own cell rather than relying on one number.

Can I make my own titanium PTLs?

Some labs do. Berkeley Lab researchers made PTLs by tape casting titanium slurry with PMMA poreformers, a low-cost and scalable method. Their best design beat a commercial titanium powder PTL by 62 mV at 4 A/cm². Making PTLs needs sintering equipment and careful control of pore structure.

 

Choosing a PTL for your electrolyzer test cell? Tell us your cell size and test plan, and we will suggest options: book a technical call.