Microwave-Induced Single-Stage CO ₂ Hydrogenation to Light Olefins over a ZnO-ZrO ₂ /SAPO-34 Tandem Catalyst

High Resolution Image Download MS PowerPoint Slide The catalytic conversion of CO 2 to light olefins offers a promising route for sustainable carbon utilization. In this work, a single-stage mixed catalyst bed consisting of ZnO-ZrO 2, SAPO-34, and SiC was employed for the direct hydrogenation of CO 2 under microwave irradiation. The mixed system enables tandem CO 2 activation and methanol-to-olefins conversion, where ZnO-ZrO 2 generates reactive intermediates and SAPO-34 provides acid sites for C–C coupling, while SiC ensures effective microwave absorption and uniform heating. Reaction performance was evaluated across varied temperatures and pressures to assess microwave-induced enhancements. Selective microwave heating of polar intermediates and interfacial polarization at the ZnO-ZrO 2 interface lower the apparent activation energy for CO 2 conversion, promoting methanol formation and enhancing olefin yields at reduced bulk temperatures. Characterization by XRD and CO 2 -TPD confirmed the formation of Zn–O–Zr interfacial sites with improved reducibility and stronger basicity, promoting more efficient CO 2 activation. Overall, microwave-assisted tandem catalysis demonstrates a highly energy-efficient pathway for converting CO 2 to valuable light olefins with a CO 2 conversion of 26.3% and olefin selectivity of 58.6%.