Enhanced photothermal dehydration of methanol over W 18 O 49 /Au/SAPO-34 catalysts with broadened light absorption

Methanol-to-olefins (MTO) process is one of the most critical pathways to produce low carbon olefins. Typically, the reaction is driven by thermal catalysis, which inevitably needs to consume large amounts of fossil fuel. Developing a new technique to substitute for the fuel burning is urgent for MTO process to improve the industry prospects and sustainability. Herein, we report a novel W 18 O 49 /Au/SAPO-34 (W/Au/S), a multifunctional photothermal catalyst for the MTO reaction. A high methanol conversion was achieved under xenonum (Xe) lamp irradiation, yielding methyl ether (ME) and ethylene as the main products. The optimized W/Au/S catalysts showed ethylene yield as high as 250 μmol in 60 min, which was 2.5 times higher than that of Au/SAPO-34. The physiochemical characterization revealed that the SAPO-34 molecular sieves were surrounded by Au and W 18 O 49 nanoparticles, which exhibited a strong localized surface plasmon resonance excitation around 540 nm and light absorption beyond 500 nm. The multifunctional catalysts showed a strong photothermal effect, arising from the broadened light absorption of Au and W 18 O 49 nanoparticles, leading to a temperature as high as 250 °C on the surface of the catalysts. Mechanism study showed that the superior ethylene selectivity of W/Au/S catalysts was attributed to the moderating acidic sites of W 18 O 49 for methanol dehydration to ethylene. This research may provide new insight for designing heterostructures to improve photo-to-chemical conversion performance and is expected to accelerate progress toward the excellent multifunctional photothermal catalysts with broad light absorption for methanol activation and C–C bond formation. Graphical abstract