Pyrolysis-catalysis is a promising method to realize the recycling of waste plastic. Thereinto, metal-support interaction (MSI) has a crucial impact on the properties and performances of catalysts. Different active metal components (Ni or/and Fe) and pre-reduction process were introduced to adjust the metal-support interaction in this work. The results showed that moderate MSI was obtained from NiFe while Ni presented the weaker MSI and a stronger one was revealed for Fe. After pre-reduction, the promotion of MSI was observed for all catalysts, leading to the increase of active metal particle size. For the carbon deposition process , a higher CNMs yield (44.4 wt%) was obtained from NiFe, followed by 30.0 wt% of Fe and 18.2 wt% of Ni. The moderate MSI and synergistic effects of two metal species contributed to the CNMs production. However, different results were observed after fresh Ni Fe catalysts were reduced. Less carbon was formed on reduced monometallic Fe or bimetallic NiFe catalyst. This might be ascribed to the stronger MSI promoted by the pre-reduction of Fe-containing catalysts, inhibiting the catalyst activity. In addition, the strengthened MSI made the CNMs growth mechanism shift from tip-model to base-model and the graphitization degree of CNMs was also decreased. Our study may provide specific guidance for the production of high-valued CNMs recycling from waste plastics.
Bin Chen,Fan Bai,Yingjie Feng,Sipu Wang,Xinyi Cao,Wei Li,Lianqin Wang,Xiaoyue Fu,Li Jin,Junfeng Zhang,Yan Yin,Michael D. Guiver
The limited surface reconstruction of NiFe alloy-based catalysts in an anion exchange membrane water electrolysis (AEMWE) restricts the utilization of active sites in the membrane electrode assembly (MEA), hindering further improvements in mass activity and AEMWE performance. Additionally, during MEA preparation using highly active powder-based catalysts, challenges such as contamination and coverage of the active sites may arise, impacting performance. This work presents an in situ anodic oxidation method to selectively leach Mo ions from pre-designed NiFe alloy particles, achieving bulk transformation and forming cation vacancy defects. Results demonstrated that the leaching of Mo ions facilitated the bulk transformation of NiFe to NiFeOxHy with an optimized electronic state, while Mo cation vacancies accelerated the deprotonation of hydroxyl (*OH) species, significantly lowering the free energy barrier required for *OOH formation. The resulting VMo-NiFe catalyst achieved an overpotential of 222 mV during rotating disk electrode (RDE) testing. After rapid in situ activation, the AEMWE equipped with a VMo-NiFe catalyst layer delivered 1.0 A cm−2 at 1.71 V, exhibiting high stability in galvanostatic and fluctuation tests. The in situ bulk transformation method developed in this work effectively enhances MEA performance and reduces the risk of activity loss during MEA preparation.
危险品化学品经营许可证（带存储）