Engineering a Pd-MXene hydrogen-supply interface on GaZnZrOx for methanol synthesis from CO2

A Pd-MX/GaZnZrO x hybrid catalyst was developed for CO 2 hydrogenation. • MXene acts as a hydrogen-delivery platform beyond a conventional support. • Interfacial coupling promotes H 2 activation and CO 2 conversion synergistically. • A methanol STY of 600.2 mg gcat −1  h −1 was achieved at 320 °C. • DFT and DRIFTS confirm an accelerated formate-mediated pathway. Efficient CO 2 hydrogenation to methanol requires a balanced interface where CO 2 activation is coupled with H 2 dissociation and subsequent hydrogenation. Herein, a Pd-modified MXene (Pd-MX)/GaZnZrO x hybrid catalyst was developed by integrating Pd-modified MXene with Ga-modified ZnZrO x oxide to overcome the limited hydrogen activation ability of Cu-free oxide catalysts. In this architecture, Pd provides H 2 dissociation sites, GaZnZrOx contributes to CO 2 adsorption and activation through its surface oxygen-related sites, and promotes the formation and hydrogenation of formate- and methoxy-related intermediates. Under 320 °C, 3.0 MPa, H 2 /CO 2  = 4:1, and GHSV = 24,000 mL gcat −1  h −1 , Pd-MX/GaZnZrO x achieved 10.5% CO 2 conversion, 83.26% methanol selectivity, and a methanol space-time yield of 600.2 mg gcat −1  h −1 , outperforming GaZnZrOₓ and Pd/GaZnZrO x while maintaining stability over 100 h. Spectroscopic characterization and DFT calculations reveal that MXene coupling enriches electrons on Pd, facilitates H 2 activation, improves interfacial adsorption behavior, and stabilizes formate- and methoxy-related intermediates. These results support a contact-dependent Pd-MX/GaZnZrO x architecture that enhances H 2 activation and facilitates the hydrogenation of CO 2 -derived intermediates over the Cu-free oxide catalyst. Download: Download high-res image (153KB) Download: Download full-size image