(521bn) Boosting Low-Temperature Dry Methane Reforming on Supported Intermetallic Ni-Zn Nanocatalysts

Large-scale carbon capture and recycling (CCR) is projected to play a crucial role in mitigating the impacts of climate change. One promising method for achieving this goal is the industrial production of chemicals and fuel from CO₂ and CH₄. Transformation of CO₂ and CH₄ into a CO-rich stream through the dry reforming of methane (DRM) at low temperatures (<500°C) is highly desirable due to its potential for economic viability and high CO₂ utilization. Despite being a well-studied reaction, conventional catalysts have limitations, including coke formation, leading to rapid catalyst deactivation. Therefore, sophisticated heterogeneous catalyst design and surface chemistry modulation are necessary to overcome these hurdles. Intermetallic nanoparticles (iNPs) composed of an ordered crystal structure and a well-defined atomic arrangement of transition and post-transition metals, provide the catalytic design space for surface chemistry modulation for improved catalytic properties.

In this work, the electronic state and surface environment of a Ni_­­-Zn intermetallic catalyst for low-temperature CO₂ reforming of methane were effectively controlled. Through careful bimetallic combination and composition tuning, intermetallic bulk structures with distinct surface compositions and structures were created, altering the surface's reactivity and selectivity through electronic, ensemble, and steric effects. The results showed that charge separated paired sites (Ni^𝛿--Zn^𝛿+) iNPs encapsulated in SiO₂ increased catalytic activity (syngas production) by a factor of 4 and exhibited enhanced stability during a 160-hour time on stream test at 450°C, while limiting coke formation by four orders of magnitude compared to monometallic Ni. This work provides an approach for surface chemistry control through bimetallic compositional tuning and modification via adsorbate/ligand in heterogeneous catalyst design for relevant reaction systems involving C-H, C=O, and C-C activation.