Highly Dispersed Metal Carbide on ZIF‐Derived Pyridinic‐N‐Doped Carbon for CO₂ Enrichment and Selective Hydrogenation

Abstract

Catalytic conversion of CO into chemicals is a critical issue for energy and environmental research. Among such reactions, converting CO into CO has been regarded as a significant foundation to generate a liquid fuels and chemicals on a large scale. In this work, zeolitic imidazolate framework-derived N-doped carbon-supported metal carbide catalysts (M/ZIF-8-C; M=Ni, Fe, Co and Cu) with highly dispersed metal carbide were prepared for selective CO hydrogenation. Under the same metal loadings, catalytic activity for CO hydrogenation to CO follows the order: Ni/ZIF-8-C≈Fe/ZIF-8-C>Co/ZIF-8-C>Cu/ZIF-8-C. These catalysts are composed of carbide or metal supported on pyridinic N sites within the N-doped carbon structure. ZIF-8-derived pyridinic nitrogen and carbide effect CO adsorption, whereas dispersed Ni or Fe carbide and metal species serve as an active site for CO hydrogenation. The supported Ni catalyst exhibits extraordinary catalytic performance, which results from high dispersion of the metal and exposure of the carbide. Based on high-sensitivity low-energy ion scattering (HS-LEIS) and line scan results, density functional theory (DFT) was used to understand reaction mechanism of selective CO hydrogenation over Ni/ZIF-8-C. The product CO is derived mainly from the direct cleavage of C-O bonds in CO * rather than decomposition of COOH*. The CO* desorption energy on Ni/ZIF-8-C is lower than that for further hydrogenation and dissociation. Comparison of Ni/ZIF-8-C with ZIF-8-C indicates that the combined effects of the highly dispersed metal or carbide and weak CO adsorption result in high CO selectivity for CO hydrogenation.

Preparation and Performances of ZIF-67-Derived FeCo Bimetallic Catalysts for CO2 Hydrogenation to Light Olefins

“…In the test temperature range, three kinds of desorption peaks of 120 °C, 270 °C, and 350 °C were mainly observed. Among them, peaks around 120 °C comes from the weakly adsorbed alkaline sites, and the peaks at 270 °C and 350 °C correspond to the alkaline sites of medium intensity chemisorption [33,59]. It can be seen that with the raise of pyrolysis temperature, the adsorption of medium intensity became less and the weak physical adsorption increased.…”

Biomass Sucrose‐Derived Cobalt@Nitrogen‐Doped Carbon for Catalytic Transfer Hydrogenation of Nitroarenes with Formic Acid

“…[24][25][26] Doping with nitrogen atoms can lead to as light distortion in the crystal lattice of the carbon materiala nd thereby cause defects. [4,[33][34][35][36][37][38] For example, Beller andc o-workersr eported the use of nanoscale iron(-III) oxide (Fe 2 O 3 )p articles surrounded by N-doped graphene layers for the selectivet ransfer hydrogenation of nitroarenes with hydrazine hydratea sh ydrogen source. [27][28][29] In the past decade, non-noblem etals incorporated into NC materials have not only become an alternative to noble-metal-based catalysts in electrocatalysis, [30][31][32] but also their excellent properties for catalytic hydrogenation have been reported.…”

“…[27][28][29] In the past decade, non-noblem etals incorporated into NC materials have not only become an alternative to noble-metal-based catalysts in electrocatalysis, [30][31][32] but also their excellent properties for catalytic hydrogenation have been reported. [4,[33][34][35][36][37][38] For example, Beller andc o-workersr eported the use of nanoscale iron(-III) oxide (Fe 2 O 3 )p articles surrounded by N-doped graphene layers for the selectivet ransfer hydrogenation of nitroarenes with hydrazine hydratea sh ydrogen source. [39] We also reported a g-Fe 2 O 3 -modified NC material for CTH of nitroarenes.…”

Tailored N-doped porous carbons via a MOF assembly process for high-performance CO2 uptake

“…28,29 Especially for ZIF-8, a great deal of attentions has been paid to develop NPC from such a N-rich and commercialized MOF to improve CO 2 uptake. [30][31][32] By using ZIF-8 as a template, furfuryl alcohol and NH 4 OH as additional carbon and nitrogen, Xu and co-workers constructed NPC with a high surface area of 2747 m 2 /g and N-containing of 2.7% at 900°C, which performed 3.9 mmol/g of CO 2 uptake at ambient condition. 33 Moreover, the direct carbonization of ZIF-8 has been studied by Guo and coworkers, in which the pore structure could be tuned by adjusting the crystal size and the carbonization temperature.…”