CO2 reforming of ethane using Ni-La intermetallic sites within a nanocapsule framework

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-07, Vol.491, p.152091, Article 152091
• Main Authors: Wang, Changzhen, Liu, Lingji, Liu, Yupeng, Yu, Xiaosheng, Chen, Zhou, Han, Yaohua, Wang, Yongzhao, Zhao, Yongxiang
• Format: Article
• Language: English
• Subjects: C2 intermediate coking/elimination; CO2 reforming of ethane; Nanocapsule; Ni-La intermetallic sites; Unconventional gas utilization
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2024.152091

NiLa intermetallic NPs inside a nanoreactor can lower the activation energy of C2H6 and CO2, which facilitates the transport/conversion of C2*, then significantly improves the dry reforming selectivity of ethane C-C bond breaking over Ni-La@Si catalysts. [Display omitted] •Dry reforming of ethane to syngas is a novel route to co-utilize CO2 and unconventional gas to get hydrogen energy.•Spatial-chemical bifunctional confinement strategy was offered by Ni-La intermetallic sites within nanocapsule material.•The nanoreactor raised an outstanding catalytic performance in DRE which is the most stable ever reported.•C2* is more likely to polymerize than C1*, but can be curbed by functional Ni-La nanoreactors.•Physical confinement from the nanocapsule framework plays a more leading role in the anti-coking formation. CO2 reforming of light alkanes from unconventional gas resources (shale gas/coalbed gas) presents an attractive route to achieve CO2 utilization and valuable chemical production. However, it remains challenging in both high stability and product selectivity due to the inevitable strong competition between dry reforming and oxidative dehydrogenation pathways. We report here a La modified Ni@SiO2 nanocapsule as the thermal-catalyst for CO2 reforming of ethane, achieving complete ethane conversion and remarkable CO2 conversion of 86.5 %, with stability for more than 200 h experiencing no carbon deposition. Detailed kinetic study, in situ characterizations and DFT calculation results revealed that the formation of NiLa intermetallic sites improved the adsorption of active oxygen species and activation of C2H6, which stabilized the key intermediate CH3CH2O* as well as the subsequent C2* cracking to CHx(O)*, leading to high selectivity toward syngas. Meanwhile, the removal of carbon deposits on Ni-La2O3 interfaces are faster than Ni surface. The synergism of spatial confinement structure provided by the nanocapsule with sufficient mechanical strength together with the chemical Ni-La2O3 interface of the enwrapped Ni-La mixed metal (oxide) NPs can timely eliminate C2* intermediates, which results in the most effective anti-coking ability during ethane reforming. This work highlights a tangible process towards unconventional (C2+) gas utilization with fine-tunable nanoreactor catalysts.