Free-standing bimetallic Co/Ni-MOF foams toward enhanced methane dry reforming under non-thermal plasma catalysis

Abstract

The bimetallic-MOF polyhedrons supported on the free-standing 3D bacterial cellulose foams (Co/Ni-MOF@BC) with both a textural advantage to induce intensive predominant filamentary microdischarge and an interfacial merit with strong alkaline absorption sites to boost CO 2 absorption capacity demonstrated an excellent DRM performance with highest CO 2 and CH 4 conversion rates at 52.31 % and 71.50 %, showing overwhelming superiority over its monometallic counterparts and compact Co/Ni-MOF powder. • An independent BC foam supported bimetallic MOF polyhedron (Co/Ni-MOF@BC) was prepared, showing the advantage of enhancing the catalyst surface for plasma assisted DRM reaction. • The co-coordination of Co and Ni ions in MOF polyhedrons enabled a structure uplift for the malleable BC nanofibers network with more abundant pores. • A network structure with abundant pores is beneficial for enhancing filamentous micro discharges and surface discharges, inducing stronger plasma catalytic interactions. • The bimetallic Co/Ni-MOF@BC exhibited a substantially improved alkaline absorption ability, favoring the more kinetically constrained CO 2 reduction. Understanding of the structure and interfacial merits that reactive metal–organic frameworks (MOFs) undergo is critical for constructing efficient catalysts for non-thermal plasma-assisted conversion of greenhouse gases. Herein, we proposed a free-standing bimetallic (Co/Ni) MOFs supported on bacterial cellulose (BC) foams (Co/Ni-MOF@BC) toward the coaxial dielectric barrier discharge (DBD) plasma-catalytic system, of which the Co/Ni ions coordination demonstrated an intriguing textual uplifting of the malleable BC nanofiber network with abundant pores up to micrometer-scale, which could impart a more intensive predominant filamentary microdischarge current to 180 mA with stronger plasma-catalytic interaction. Remarkably, compared to the monometallic MOF@BC foams, this bimetallic Co/Ni-MOF@BC also delivered a substantially improved alkaline absorption ability as further confirmed by the CO 2 - temperature-programmed desorption (TPD) result. Benefiting from its 3D superiority and synergy of Co/Ni dual-regulation, the Co/Ni-MOF@BC, therefore, displayed the highest CO 2 and CH 4 conversion rates to 52.31 % and 71.50 %, which was above 1.5 and 1.3 times higher than those of monometallic counterparts and Co/Ni-MOF powder. Additionally, its robust cycling performance has also been evidenced by the excellent long-time DRM performance, unchanged crystallinity, morphology, and surface chemical states. By taking both the catalyst existing form and interfacial optimization of MOFs into consideration for designing a unique DRM catalyst, we believed this free-standing 3D Co/Ni-MOF@BC foams could inspire more research outputs on the design of functional catalysts with abundant pores and alkaline absorption sites to accelerate the redox kinetics of CO 2 /CH 4 conversion.

Topics & Concepts