Enhancing the syngas production yield from ethane and CO₂ by optimizing the Pd–O–Ce interface

CO₂-assisted oxidative dehydrogenation of ethane (CO₂-ODHE) and dry reforming of ethane (DRE) have provided a promising way to simultaneously upgrade CO₂ and ethane to produce value-added industrial feedstocks, such as syngas (CO and H₂) or ethylene. CeO₂-supported Pd bimetallic catalysts have been demonstrated to be efficient catalysts for these reactions. In particular, the Pd–O–Ce and Pd–O–Fe (or Pd–O–In) interfaces were verified as the key active sites for producing syngas and ethylene, respectively. However, how to regulate the amount of interface to further enhance the product yield is still a major challenge in this area. In this study, we show that the ratio of the Pd–O–Ce interface can be optimized through the CeO₂ nano-island strategy. CeO₂ nano-islands with different loadings and sizes are grafted onto the high-surface-area SiO₂ and are then used for anchoring PdFe_n bi-metals, thus leading to the formation of interfaces with different amounts of Pd–O–Ce. The results show that when the Ce loading reaches 15 wt.%, the supported PdFe_n catalyst has the highest ratio at the Pd–O–Ce interface, resulting in a significant increase in the syngas yield (879.1 μmol·g⁻¹·min⁻¹ for CO and 508.1 μmol·g⁻¹·min⁻¹ for H₂ respectively), which is the best among all the reported state-of-the-art catalysts in the literature. At the same time, the ethylene production rate can be maintained at a high level of 172.5 μmol·g⁻¹·min⁻¹.