Influence of Nickel Loading on Reduced Graphene Oxide-Based Nickel Catalysts for the Hydrogenation of Carbon Dioxide to Methane

Abstract

In this study, a series of novel nickel catalysts supported on reduced graphene oxide nanosheets (Ni/rGO) with Ni loadings of 10, 15 and 20 wt% were successfully synthesized via the incipient wetness impregnation method. The physicochemical properties of the catalysts and rGO support were thoroughly characterized by thermogravimetric analyser, X-ray diffraction, fourier-transform infrared spectroscopy, Raman spectroscopy, N2 adsorption-desorption, temperature programmed reduction, temperature programmed CO2 desorption and field emission scanning electron microscopy with energy dispersive X-ray spectroscopy. The properties of the catalysts are correlated to its catalytic activity for CO2 methanation which were investigated using three-phase slurry reactor at low temperature and pressure of 240 °C and 10 bar, respectively. Among the three catalysts of different Ni loading, Ni15/rGO shows the highest activity of 51% conversion of CO2 with total selectivity towards CH4. N2-physisorption and CO2-TPD analysis suggest that high catalytic performance of Ni15/rGO is attributed to the high surface area, strong basic sites and special support effect of rGO in anchoring the active metal.

Aromatic Ethers Induced Electronic Structure Reconstruction on Encapsulated Nickel Catalysts for High-Performance Catalytic Hydrogenation

“…The lowtemperature reduction peak at 127−284 °C is likely associated with the reduction of larger NiO particles, while the high-temperature reduction peak at 361−496 °C can be attributed to NiO particles strongly interacting with the carbon support. 54 It is worth noting that the O 5 -Ni@OC-80 °C-2 h catalyst does not exhibit a hydrogen consumption peak at lower temperatures, further indicating that H 2 cannot penetrate the GLS to undergo NiO reduction within the catalyst. However, hydrogen consumption peaks are observed at elevated temperatures (400 and 537 °C).…”

Graphene-Encapsulated Transition Metal@N/C Catalysts for Catalytic Copyrolysis of Biomass and Waste Plastics: Production of Linear α-Olefins and Aromatics

“…48 Similarly, sharp and broad reduction regions are observed around 250−350 °C for the Niloaded catalyst, indicating the reduction of Ni 2+ species that strongly interact with the graphene support. 47 The Znincorporated RGrO catalysts showed a broad reduction zone observed around 400−550 °C, indicating the reduction of surface ZnO, and another peak around 650−750 °C, indicating strong metal and support interaction.…”

Graphene-based nanomaterials for CO2 capture and conversion

“…Summary of utilization of graphene-based nanomaterials for different applications of CO 2 hydrogenation is provided in Table 8.4 (Deerattrakul et al, 2016;Fan & Wu, 2016;Jurca et al, 2019;Liu et al, 2019;Mohd Ridzuan et al, 2020;Nguyen et al, 2015;Primo et al, 2019;Witoon et al, 2018).…”