Ammonia Hydrogen Carrier Patents: Leaders & Filing Trends 2026
- Filing peaked in 2024 at 69 families after years of near-flat activity through 2022, suggesting the field only recently moved from lab-scale to commercial interest.
- Catalysis and separation dominate the claim map C01B and B01J together cover the bulk of records, while combustion-side IPC classes like F02B and F02M remain comparatively thin.
- One assignee pair anchors nearly all co-filing Hitachi Zosen and Toyota co-file far more than any other pair in the dataset, pointing to a concentrated engine-and-cracking collaboration.
What the ammonia-carrier patent record actually shows
Ammonia is being pursued as a way to move hydrogen without the pressure or cryogenic burden of storing hydrogen itself, and the patent record reflects a field organised around three technical jobs: cracking ammonia back into hydrogen, storing and transporting it at usable density, and burning or converting it while controlling NOx. The 205 families captured here span a 2015-2026 filing window, with the receiving-office mix — PCT, Europe, the US, Singapore, the UK and Australia all represented in double digits — showing this is being filed as an international problem, not a single-country one.
Filing activity was close to flat through the late 2010s and early 2020s, then rose sharply into 2024. Because publication typically lags filing by around 18 months, the most recent one to two years in any trend chart will understate real activity — the actual 2025-2026 filing volume is likely higher than what has published so far.
Filing trend and technology composition
Two views of the same 205-family dataset: how filing volume moved year over year, and which IPC subclasses carry the claim density.
A late, sharp ramp rather than steady growth
Filings sat near zero through 2017 and stayed modest through the 2022 midpoint (6 families), then climbed to a peak of 69 in 2024. That shape is consistent with a technology that moved from exploratory filing to active claim-staking inside a narrow window, rather than one that has been building steadily for a decade.
Catalysis and separation outweigh combustion
C01B (non-metallic elements and inorganic compounds) appears in 197 of 205 records, and B01J (catalytic processes) in 74 — together these anchor the cracking-and-conversion side of the field. B01D (separation, 58) is also heavily claimed. Combustion-adjacent classes — F02C gas turbines, F25B refrigeration, F02B and F02M internal-combustion and fuel supply — each sit in the low teens, indicating the downstream use of cracked hydrogen or direct ammonia combustion is comparatively under-filed relative to the cracking step itself.
Shares are the percentage of the 205 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Ammonia as Hydrogen Carrier with Eureka
This page is one run against one query. Ask Eureka your own question about ammonia as hydrogen carrier and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records in this corpus
US9341111B2 — Ammonia-Engine System (Hitachi Zosen, 2016)
The patent describes an ammonia-fuelled engine system that adds an ammonia oxidising device between the engine and the ammonia cracking device, so the cracking catalyst can be kept at its required operating temperature even under low-load conditions where exhaust gas alone runs too cool to sustain the reaction.Filed by Hitachi Zosen Corporation; published 2016-05-17.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | WO2021257944A1 | Ammonia cracking for green hydrogen | 90 |
| 2 | US20190084831A1 | Ammonia cracking | 58 |
| 3 | JP1993330802A | Production of ammonia-cracked gas and production of hydrogen | 57 |
| 4 | WO2022243410A1 | Ammonia cracking for hydrogen production | 50 |
| 5 | WO2021257944A9 | Ammonia cracking for green hydrogen | 45 |
| 6 | WO2022265650A1 | Ammonia cracking process | 45 |
| 7 | JP2010121509A | Ammonia-engine system | 43 |
| 8 | WO2022265648A1 | Ammonia cracking for green hydrogen with NOX removal | 39 |
| 9 | WO2022265649A1 | Ammonia cracking for green hydrogen | 38 |
| 10 | US11084719B2 | Ammonia cracking | 36 |
Citation counts are drawn from the searched corpus and skew toward older filings; treat them as a signal of influence within this dataset, not as a ranking of current technical importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three patterns stand out once the raw counts are read against filing dates and IPC distribution.
The field is young and still accelerating
A midpoint of just 6 families in 2022 followed by a jump to 69 in 2024 signals that most of the active claim-staking in ammonia cracking and carrier chemistry has happened in the last two to three years. Given the typical 18-month publication lag, 2025-2026 activity is understated in the raw chart.
Cracking chemistry is the crowded core
Nearly every family in this dataset touches C01B, with B01J catalysis and B01D separation close behind. New filers should expect dense prior art on catalyst formulation and gas separation, and should look instead at the thinner combustion and refrigeration classes for open ground.
Co-filing is rare and concentrated
Only 10 co-assignee pairs exist across the whole dataset, and one pair — an engine-and-cracking-device collaboration — accounts for 9 of the co-filed families. Most other assignees are filing solo, which suggests the field has not yet consolidated around shared standards or joint-development structures.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to ammonia as hydrogen carrier, with the prior art for and against each one.
Who is filing, and who has gone quiet
Several assignees with historical filings show zero activity in the latest year, including some with a full year-over-year drop to zero — a pattern worth checking against each company's public roadmap rather than reading as exit from the field, since publication lag can hide filings still in the pipeline.
Historical leaders show no recent publications
A number of assignees with meaningful filing histories in this dataset, including industrial gas and catalyst specialists, show zero families in the most recent year and, in several cases, a full year-over-year decline. This is consistent with the publication lag rather than necessarily a pullback in R&D.
One engine-cracking partnership stands out
The strongest co-assignee relationship in the dataset links an engine manufacturer with a shipbuilding and industrial-equipment group, filing jointly on ammonia-engine and cracking-device systems. No other pair approaches this volume of shared filings.
Filing is genuinely international
PCT filings lead, followed closely by the European and US offices, with Singapore, the UK and Australia each carrying a double-digit share. That spread indicates applicants are seeking protection across multiple shipping and energy markets rather than concentrating on one home jurisdiction.
| Assignee | Recent year | YoY |
|---|---|---|
| Air Products and Chemicals, Inc. | 0 | — |
| Johnson Matthey Plc (UK) | 0 | -100% |
| Casale SA | 0 | -100% |
| Haldor Topsoe A/S | 0 | -100% |
| Johnson Matthey Davy Technologies | 0 | -100% |
| Hitachi Zosen Corporation | 0 | — |
| Toyota Motor Corporation | 0 | — |
| Nuovo Pignone Tecnologie S.r.l. | 0 | -100% |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, white-space filing, or partner scouting.
Check freedom-to-operate against the cracking core
With 197 of 205 families touching C01B and 74 touching B01J, any new cracking-catalyst or separation filing should be checked against this dense core before drafting claims.
Run a freedom-to-operate check in EurekaMap the thin combustion and refrigeration classes
F02B, F02M and F25B each carry only a handful of families relative to the cracking core, which is where a first-mover claim is more likely to stand cleanly.
Explore white space in EurekaTrack assignees that have gone quiet
Several historically active filers show zero publications in the latest year; watching their pipeline over the next 18 months will clarify whether that reflects a real slowdown or publication lag.
Set up assignee monitoring in EurekaCommon questions about ammonia hydrogen-carrier patents
Most filings sit in C01B, the IPC subclass for non-metallic elements and inorganic compounds, which appears in 197 of the 205 families in this dataset. B01J, covering catalytic processes, is the second most common at 74 families, since cracking ammonia into hydrogen and nitrogen requires a catalyst. B01D, separation processes, is also heavily represented at 58 families because cracked gas typically needs purification before use. A new filing in this space should expect to be searched against all three classes together, not just one.
The dataset shows filing concentrated among industrial gas, catalyst and heavy-equipment companies, with the strongest documented collaboration being a co-filing relationship between an engine manufacturer and a shipbuilding and industrial-equipment group that accounts for 9 shared families. Several other established assignees, including industrial gas and catalyst specialists, show no publications in the most recent year, which may reflect the normal 18-month gap between filing and publication rather than reduced activity. Anyone scouting partners or licensors should check each company's recent public announcements alongside the patent record.
Cracking-related chemistry is far more heavily claimed. C01B and B01J, the classes tied to breaking ammonia down into hydrogen and catalysing that reaction, together dominate the dataset, while combustion-adjacent classes such as F02B (internal combustion engines) and F02M (fuel supply) each sit at only 12 families. This gap suggests that engineering ammonia-fuelled combustion systems, rather than cracking catalysts, currently has more open claim space, though it also means less prior art exists to build on.
Filing was essentially flat through the late 2010s, with the 2022 midpoint at just 6 families, before rising sharply to a peak of 69 in 2024. That is a late, steep ramp rather than steady multi-year growth, consistent with the technology moving from research interest into active commercial claim-staking only recently. Because publications lag filing by roughly 18 months, the true 2025-2026 volume is almost certainly higher than what has published to date.
The thinnest IPC classes relative to the cracking core are combustion and thermal-management related: F02B and F02M (each 12 families), F25B refrigeration (15), and F02C gas turbines (18). These cover areas like NOx aftertreatment tuned to ammonia combustion, boil-off and refrigeration integration for ammonia transport, and marine gas-turbine co-firing. A first claim in one of these areas is less likely to run into the dense prior art that dominates cracking-catalyst and separation filings.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
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Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.