Interfacial chemical regulation and catalytic performance of CeO2-TiO2/fly ash heterojunction photocatalyst for hydrogen evolution

A CeO 2 -TiO 2 /fly ash heterojunction uses waste-derived fly ash as a porous, defect-rich interfacial support. • Hydroxyl groups and defect sites in fly ash anchor TiO 2 /CeO 2 nanodomains, suppress aggregation and stabilize interfaces. • FTC extends the visible-light absorption edge to ca. 550 nm and narrows the apparent bandgap to ca. 2.25 eV. • Photocurrent, IPCE, EIS, EPR and a ca. 49 ns TRPL lifetime support enhanced charge separation and transfer. • In situ 13 C CP-MAS NMR tracks stepwise methanol oxidation, linking hole consumption to electron delivery for H 2 evolution. Solar-driven photocatalytic hydrogen evolution stores sunlight in chemical bonds, while coal fly ash provides a low-cost route to valorize industrial solid waste. Yet TiO 2 - and CeO 2 -based photocatalysts remain limited by weak visible-light absorption and rapid charge recombination, and the interfacial function of fly ash is poorly defined. Herein, we report a CeO 2 -TiO 2 /fly ash (denoted as FTC) heterostructured compositefor hydrogen evolution combination with the numerous characterizations of structural, optical, photoelectrochemical, spectroscopic and in situ solid-state C 13 cross-polarization magic-angle-spinning nuclear magnetic resonance analysis. The FTC composite extends absorption to approximately 550 nm, narrows the apparent bandgap to ca. 2.25 eV and achieves efficient hydrogen evolution of 32 μmol h −1 g −1 under an air mass 1.5 global (AM 1.5G) irradiation. Fly ash supplies hydroxyl- and defect-rich anchoring sites for TiO 2 -CeO 2 interfaces stabilization, thus promoting charge separation and couple methanol oxidation with electron delivery for proton reduction. This work establishes waste-derived interface regulation as a practical strategy for low-cost photocatalytic solar-fuel generation. Download: Download high-res image (243KB) Download: Download full-size image