Light or acid? Suppressing water deactivation in SAF production via phenyl-mediated charge transfer in WOx/ZrOx-functionalised PMOs

The aviation sector contributes ∼2.5 % of global energy-related CO 2 emissions, driving demand for sustainable aviation fuel production (SAF) from biomass. However, water, whether intrinsic or produced in situ, often drives on-stream catalyst deactivation, reducing efficiency and creating barriers to process scale-up. Here, we present an exciting new approach using WO x /ZrO x -functionalised periodic mesoporous organosilica (PMO) photocatalysts that exhibit exceptional stability and performance under aqueous conditions. The incorporation of bis(triethoxysilyl)benzene (BTSB) into the PMO framework not only enhances surface hydrophobicity and acidity but also strategically positions organic π-conjugated phenyl groups next to WO x /ZrO x active sites. These phenyl moieties act as conductive pathways, significantly enhancing charge separation and transfer from the light-activated WO x /ZrO x heterojunctions to the reactants. This synergistic control of surface polarity, acidity, and charge transfer mitigates water-induced deactivation and precisely directs reaction pathways, enabling the first-ever water-tolerant, solvent-free photocatalytic conversion of furfural (FAL) and cyclopentanone (CPO) to 2,5-bis(2-furylmethylidene) cyclopentanone (F 2 Cp), a crucial SAF precursor. Under UV irradiation (365 nm, 80 °C) and a 3:1 CPO:FAL ratio, WO x /ZrO x /PMO(50 %) delivered 92.9 % FAL conversion and 49.9 % F 2 Cp yield after 6 h, corresponding to a twofold enhancement in mass-normalised activity relative to SBA-15-supported analogues, and 3–4-fold enhancement over visible light operation. The catalyst remained stable over three reuse cycles without significant deactivation. By contrast, an unwashed control lost ∼35 % activity due to reversible surface carbon accumulation. These findings establish a new paradigm for designing stable, selective photocatalysts, enabling scalable and energy-efficient biomass conversion technologies. • Water-tolerant, solvent-free photocatalytic synthesis of SAF precursor F 2 Cp from furfural and cyclopentanone. • Synergistic WO x /ZrO x /PMOs: Hydrophobic pores prevent deactivation; tuneable electronics boost charge transfer. • Enhanced Activity: WO x /ZrO x /PMO(50 %) is 2 x more active than SBA−15 analogue; 3-4 x faster under UV than visible light. • Unique Water-Driven Mechanism: Controlled H 2 O addition increases rates up to 3 x as hydrophobic environment drives product formation. • Exceptional Stability: Catalysts are highly stable and regenerable, maintaining activity over multiple cycles with simple washing.