Homolytic H2 dissociation for enhanced hydrogenation catalysis on oxides
Chengsheng Yang1, Sicong Ma2, Yongmei Liu1
1Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai, 200438, China.
Researchers identified how hydrogen splits on gallium oxide (Ga2O3) surfaces, boosting hydrogenation reactions. This discovery enhances oxide hydrogenation capabilities for cleaner chemical production.
Area of Science:
- Catalysis
- Surface Science
- Materials Chemistry
Background:
- Efficient hydrogenation reactions are crucial but limited by low hydride coverage and activity on oxide surfaces.
- Understanding hydrogen dissociation pathways on oxides is key to improving catalytic performance.
Purpose of the Study:
- To quantitatively distinguish between homolytic and heterolytic hydrogen dissociation on Ga2O3.
- To elucidate the role of coordinatively unsaturated Ga3+ in enhancing hydrogenation.
Main Methods:
- Transient kinetic analysis.
- Infrared (IR) spectroscopy.
- Mass spectrometry (MS).
Main Results:
- Identified coordinatively unsaturated Ga3+ as a key site for homolytic H2 dissociation.
- Achieved high hydride coverage on Ga2O3 (H/surface Ga3+ ratio of 1.6, H/OH ratio of 5.6).
- Demonstrated that Ga-Ga distance, influenced by Ga3+ coordination, governs homolytic dissociation effectiveness.
Conclusions:
- Tuning Ga3+ coordination and hydride coverage/activity significantly enhances CO2 hydrogenation.
- Achieved a 4-6 fold increase in hydrogenation of CO2 to CO, methanol, or light olefins.
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