Enhanced photothermal dehydration of methanol over W18O49/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 W18O49/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 mu mol 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 W18O49 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 W18O49 nanoparticles, leading to a temperature as high as 250 degrees 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 W18O49 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.

Automated summary

This study reports a novel W18O49/Au/SAPO-34 multifunctional photothermal catalyst for the methanol-to-olefins (MTO) reaction, which exhibits excellent methanol conversion and ethylene yield. The physiochemical characterization reveals the properties of the catalyst and the role of W18O49 in regulating ethylene selectivity. This research provides new insights for designing heterostructures to improve photo-to-chemical conversion performance.