Solar Thermochemical Redox Cycle Patents 2026 — PatSnap Eureka
Solar Thermochemical Redox Cycle Patents 2026
Solar thermochemical redox cycles split H₂O and CO₂ using concentrated solar heat, producing hydrogen and synthesis gas without electricity conversion. This dataset snapshot covers 13 patents and 30+ literature records spanning 2010–2026.
Two-Step Solar Redox: From Metal Oxide to Green Fuel
Solar thermochemical redox cycles (STRC) use concentrated solar radiation to drive a two-step metal oxide sequence: thermal reduction at 1,400–1,600°C releases O₂, then re-oxidation at 800–1,100°C with H₂O or CO₂ produces H₂ or CO. The net reaction splits water or carbon dioxide using solar energy as the only external input, with no intermediate electricity conversion.
Among the dominant redox material families identified in this dataset, ceria (CeO₂/CeO₂₋δ) is consistently rated as the benchmark due to fast oxidation kinetics, reversibility, and thermal stability. Perovskites offer higher oxygen exchange capacity per cycle but slower kinetics. High-entropy oxides (HEOs) represent the most recent material class, designed to overcome the ceria/perovskite trade-off through configurational entropy effects.
The field spans three developmental phases in this dataset: a foundational phase (2010–2016) establishing volatile and non-volatile cycle concepts; a development and scaling phase (2017–2021) focused on reactor prototyping, ceria kinetics, and system integration; and a maturation phase (2022–2026) targeting heat recuperation, HEOs, direct air capture integration, and adaptive control under variable irradiance.
In this dataset, Chinese institutional filers account for approximately 77% of all identified patent records by count, with 10 of 13 patents carrying CN jurisdiction. In retrieved records, all active Chinese patents represent university and research institute filers, reflecting state-directed R&D investment. US and European assignees each account for 2 patents in this dataset, concentrated in national laboratories and individual inventors.
Technology Clusters and Efficiency Benchmarks Across the Dataset
Retrieved records in this dataset span four primary technology clusters — ceria-based cycles, perovskite/HEO materials, reactor architecture/heat recovery, and methane-assisted hybrid cycles — each with distinct efficiency profiles and patent activity patterns from 2010 to 2026.
Patent & Literature Records by Technology Cluster (Dataset Snapshot)
Ceria-based non-volatile cycles account for the largest share of literature records in this dataset, followed by reactor architecture and heat recovery systems, reflecting the benchmark role of CeO₂ across experimental and review publications retrieved.
↗ Click bars to exploreReported Solar-to-Fuel Efficiency Ranges by Approach (Literature Dataset)
Efficiency values reported across retrieved literature records in this dataset span from 1–12% experimentally to modeled values exceeding 40%, with methane-assisted cycles and advanced heat recuperation designs occupying the highest projected efficiency ranges.
↗ Click bars to exploreKey Application Areas for Solar Thermochemical Redox Cycles
Retrieved patents and literature in this dataset identify five principal application domains for STRC technology: green hydrogen production, solar synthetic fuels, CSP with thermochemical energy storage, distributed polygeneration, and CO₂ utilization with carbon removal.
UAE Solar Hydrogen Production
A 2022 techno-economic analysis explicitly modeled CSP-driven STRC for hydrogen export from the United Arab Emirates under realistic meteorological conditions. The study benchmarks solar-to-H₂ efficiency and compares STRC against competing pathways including PV-electrolysis and photoelectrochemical routes for sunbelt regions. It positions STRC as a viable long-term pathway for renewable H₂ destined for fuel cells or liquid fuel synthesis.
Green HydrogenSaudi Arabia Solar-to-Liquid Fuels
Two 2021–2022 studies model integrated direct air capture, STRC syngas production, and Fischer-Tropsch or methanol synthesis pathways for Saudi Arabia and comparable locations. The DLR 2022 DE patent formally extends the STRC process chain to downstream organic compound synthesis, targeting carbon-negative liquid fuel production. Techno-economic assessment confirms the concept is technically coherent, with DAC cost reduction and STRC scale-up identified as the key remaining barriers.
Solar FuelsCSP Thermochemical Storage Plant
A 2021 techno-economic analysis demonstrates a 111.7 MWe CSP system using CaAl₀.₂Mn₀.₈O₂.₉₋δ (CAM28) as both heat storage medium and heat transfer agent, integrated with a Brayton combined cycle power block achieving turbine inlet temperatures of 1,200°C. The redox material serves a dual role as both fuel producer and high-energy-density thermal storage medium, enabling dispatchable solar power generation.
Thermochemical StorageChina Distributed Polygeneration Systems
China University of Petroleum (East China) filed two 2023 CN patents on thermochemical cooling-heating-power polygeneration based on a composite solar reactor. North China Electric Power University filed CN patents in 2023 and 2024 on a solar-driven reversible solid oxide cell (RSOC) distributed polygeneration system coupling CSP-driven methane reforming with RSOC electrolysis and fuel cell modes. These filings reflect a broader pattern of Chinese university IP covering combined cooling, heat, and power from STRC.
Distributed PolygenerationKey Patent Assignees in Solar Thermochemical Redox Cycles (Retrieved Records)
In this dataset, Chinese universities and national research institutes account for approximately 77% of the 13 identifiable patent records, with the Chinese Academy of Sciences holding the highest count at 4 patents in retrieved records. US and European assignees each contribute 2 patents in this dataset, concentrated in national laboratories and individual inventors.
Top Assignees by Patent Filing Count in Retrieved Records (Dataset Snapshot)
↗ Click bars to exploreChinese Academy of Sciences
The Chinese Academy of Sciences holds 4 patents in this dataset across two institutes: the Institute of Engineering Thermophysics (3 active CN patents from 2015 and 2017 on solar thermochemical fuel production, plus a 2025 pending patent on solar-driven chemical looping wet reforming for hydrogen production and CO₂ separation) and the Institute of Electrical Engineering (2 CN patents from 2023 and 2026 on photocatalytic–high-temperature thermochemical coupled fuel production with machine learning control). All active patents use CeO₂, ZnO, or Fe₂O₃ as oxygen carriers at reduction temperatures of 1,000–1,800°C.
China — CNNat’l Tech. & Eng. Solutions of Sandia
National Technology & Engineering Solutions of Sandia, LLC holds 1 active US patent (2017) in this dataset for a cascading pressure reactor and method for solar-thermochemical reactions, which introduced multi-chamber reactors operating at differential pressures to reduce O₂ partial pressure during ceria reduction — a key thermodynamic lever for improving cycle efficiency. This represents the sole active US patent in this dataset from a federal laboratory, with the earlier ABENGOA SOLAR LLC US patent (2015) now inactive due to corporate restructuring.
United StatesFive Directions Shaping STRC Innovation in 2022–2026
The most recent filings and publications (2022–2026) in this dataset point to five converging directions: intelligent adaptive control, photocatalytic–thermochemical hybridization, high-entropy oxide materials, DAC integration for carbon-negative fuels, and photothermal catalytic dry reforming.
Intelligent Adaptive Control Under Variable Irradiance
Harbin Institute of Technology’s 2023 and 2025 CN patents introduce CFD-based multi-physics reactor models combined with meteorological forecasting to dynamically switch between two-step redox and methane-assisted reduction depending on available solar irradiance. This operability-focused approach marks a shift from static thermodynamic design toward closed-loop operational intelligence, optimizing both economic and environmental performance in real time. The patents are both active and represent the most recent embodiment of this control strategy in this dataset.
High-Entropy Oxides as Next-Generation Redox Materials
The 2022 literature record on thermochemical properties of high-entropy oxides (HEOs) identifies this multicomponent single-phase class as potentially transformative, offering larger configurational entropy contributions that reduce oxygen release temperatures while retaining good oxidation kinetics. HEOs directly address ceria’s low specific O₂ exchange capacity (δ ≈ 0.05–0.25) and perovskites’ kinetic penalties. The first commercially viable post-ceria material based on HEO chemistry would represent a significant IP opportunity in this space.
Ceria vs. Perovskites: Key Performance Dimensions from the Dataset
Click any row to explore further.
| Dimension | Ceria (CeO₂/CeO₂₋δ) | Perovskites (e.g. La₀.₆Ca₀.₄MnO₃) |
|---|---|---|
| Material Type | Non-volatile fluorite oxide | Non-volatile ABO₃ structure |
| Reduction Temperature | ~1,400–1,600°C | ~1,200–1,400°C (composition-dependent) |
| Oxidation Temperature | 800–1,100°C | 800–1,000°C |
| O₂ Exchange Capacity (δ) | δ ≈ 0.05–0.25 (low specific capacity) | Higher per-cycle oxygen exchange capacity |
| Oxidation Kinetics | Fast — consistently identified as benchmark | Slower — greater kinetic penalty |
| H₂O/CO₂ Flow Requirement | Moderate | High — greater gas-phase heat recuperation needed |
| Reversibility / Stability | High thermal stability, reversible | Composition-dependent; some degradation risk |
| Dataset Assessment | Confirmed benchmark across all comparative studies in dataset | Promising capacity but kinetic limitations confirmed in 2018 study |
Frequently Asked Questions: Solar Thermochemical Redox Cycles
A solar thermochemical redox cycle uses concentrated solar radiation as high-temperature process heat to drive a two-step metal oxide reaction sequence. In step one (thermal reduction), a metal oxide releases O₂ at typically 1,400–1,600°C. In step two (oxidation), the reduced oxide reacts with H₂O and/or CO₂ at 800–1,100°C to produce H₂ and/or CO. The net reaction splits water or carbon dioxide using solar energy as the only external input, without intermediate electricity conversion.
Ceria (CeO₂/CeO₂₋δ) is consistently identified as the benchmark material across experimental and review literature in this dataset due to fast oxidation kinetics, reversibility, and thermal stability. Perovskites (e.g. La₀.₆Ca₀.₄MnO₃) offer higher oxygen exchange capacity per cycle but suffer from slower kinetics. High-entropy oxides (HEOs) are an emerging class. Earlier benchmark materials include ferrites and nickel-ferrites, and the Zn/ZnO volatile cycle is covered in the foundational 2010 literature.
Experimental solar-to-fuel efficiencies are typically reported at 1–12% across literature records in this dataset. A fixed-bed ceria reactor array with solid-phase heat recovery achieves a projected 27% efficiency. Methane-assisted isothermal cycles approach ~30%. Advanced modeled designs with perfect solid- and gas-phase heat recuperation and a solar concentration ratio of 5,000 exceed 40% in thermodynamic projections from ETH Zurich research cited in the dataset.
Among the 13 patents with assignee and jurisdiction data retrieved in this dataset, China (CN) accounts for at least 10 records, representing approximately 77% of the total. Key Chinese assignees include the Chinese Academy of Sciences (4 patents), Harbin Institute of Technology (2 patents), Beijing Institute of Technology (2 patents), and North China Electric Power University (2 patents). The US contributes 2 identifiable patents (Sandia National Laboratories, HENRY ASEGUN), and Europe contributes 2 (DLR DE, ERICKSON WO).
Heat recuperation is identified in this dataset as the decisive efficiency lever. Theoretical solar-to-fuel efficiencies span from 1–12% experimentally to over 40% modeled with perfect solid- and gas-phase recuperation. Experimental validation of thermocline heat recovery achieving 70% extraction effectiveness from a 4 kW solar reactor was reported in 2023 literature in this dataset. A fixed-bed receiver-reactor array concept at ETH Zurich projects 81% solid-phase heat recovery effectiveness.
Multiple 2021–2022 studies in this dataset model end-to-end value chains combining direct air capture (DAC) of atmospheric CO₂ with STRC syngas production and Fischer-Tropsch or methanol synthesis. DLR’s 2022 DE patent formally covers the downstream organic synthesis step as part of the STRC process chain. The combination represents a complete solar-to-liquid (StL) pathway; remaining barriers identified in the dataset are DAC cost reduction and STRC scale-up, both active targets for EU Horizon Europe projects.
Data and insights on this page are based on a limited patent and literature dataset and are for reference only. Figures may not represent the complete technology landscape.