This landscape identifies 30 patent families that combine photocatalysis terminology with explicit durability framing — stability, deactivation resistance or anti-photocorrosion — inside the core catalyst-structure IPC classes. That is a small, narrowly defined set compared to the broader photocatalysis literature, because it excludes general photocatalytic-activity filings that do not address degradation or corrosion. Because the search is deliberately narrow, treat this as a count of durability-specific claims, not of photocatalysis patents overall.

Not yet in a pronounced way. Filing moved from zero in 2017 to a midpoint of 3 families in 2022 and a peak of only 4 in 2025, which is flat-to-slightly-rising rather than an accelerating trend. The most recent one to two years are also understated because of the typical 18-month lag between filing and publication, so the true 2025–2026 picture will only become clear once later filings publish. On current evidence this reads as an early-stage, still-forming niche rather than a hot area.

Water and wastewater treatment is the leading application overlay, appearing in roughly half of all records classified under C02F alongside the core catalysis classification. Coatings, polymer additives, polymer compositions and separation processes each appear in a much smaller number of records, at 3–4 apiece. This means durability claims in this space are more often framed around water-treatment deployment than around coatings, air cleaning, or structural applications, which remain comparatively thin.

The assignee base is fragmented, spanning universities, a Korean electronics manufacturer, and individual filers, with only five recorded co-assignee relationships across the whole dataset. The strongest collaboration pairs a Korean university technology-transfer office with a major electronics manufacturer, appearing twice. No single assignee shows filing activity in the latest tracked year, which is consistent with the overall flat trend rather than indicating any one firm's retreat from the space.

US20190381476A1, filed by Flux Photon Corporation, claims a photocatalytic device architecture that spatially separates radiation-generated electrons and holes before they reach the reactant flow, directly targeting the electron-hole recombination problem that limits photocatalytic efficiency. Anyone building a device that manages charge-carrier separation at the catalyst surface to improve reaction specificity should review this filing's claim scope closely. Designing around it would likely mean using a different mechanism to reduce recombination, rather than a spatial-separation architecture with the same functional effect.