Direct Hydrogenolysis of Cellulose to Methane Utilizing Rare‐Earth Promoted Nickel Catalysts

Abstract

Cellulose is one of the main components of plant matter, which makes it a viable target for biomass conversion to fuels. The direct conversion of cellulose to methane utilizing nickel‐based catalysts often has challenges associated with it. Carbon agglomeration creating nickel‐carbon nanoparticles deactivating catalytic hydrogenation of cellulose has been well reported. Utilizing rare‐earth metals as promoters increases the conversion of cellulose to methane, albeit with deactivation of the catalyst in the form of nickel‐rare‐earth‐carbon nanoparticles. Adding an additional zinc metal promoter eliminates the carbon agglomeration and allows for increased methane yields. Herein, we report an 81 % methane yield from cellulose in 48 hours utilizing a Ni/Zn/Y/Al2O3 catalyst at 225 °C and under 50 bar H2 pressure.

Phosphate assisted integrated carbon dioxide capture and conversion to methane

“…Heterogenous catalysts based on metals like ruthenium and nickel oen serve as methanation catalysts when a gas stream of CO 2 is used as the reagent in the well-known Sabatier process. 26,27 These ow reactions are routinely performed at relatively low pressures, but at higher reaction temperatures of 300-400 °C or above. There are reports on utilizing heterogenous catalysts in capture and conversion technologies.…”

Metal hydroxide assisted integrated direct air capture and conversion to methane with Ni/Al2O3catalysts

“…However, earth abundant metals, like nickel have also been shown to perform methanation reactions. [24][25][26][27] Capturing CO 2 with metal hydroxides to form bicarbonate or carbonate salts has also been researched and circumvents some of the issues with amine based systems including the discussed volatility and degradation concerns. 28,29 Recently, it was reported by Prakash et al that bicarbonate salts can be hydrogenated to methanol over a Cu/ZnO/Al 2 O 3 catalyst.…”

“…However, earth abundant metals, like nickel have also been shown to perform methanation reactions. 24–27…”

CO2 Capture and Direct Air CO2 Capture Followed by Integrated Conversion to Methane Assisted by Metal Hydroxides and a Ru/Al2O3 Catalyst

“…[37] Heterogeneous catalysts based on ruthenium have also been shown to convert CO 2 and other carbon sources to methane. [22,[50][51][52][53][54][55] In general, these ruthenium based catalysts are able to perform the reactions at a faster rate than the nickel based ones. [43,56,57]…”

“…Oligomeric and polymeric amines have been shown to capture CO 2 efficiently from the atmosphere, but can be susceptible to oxidative degradation [30,32] . Phosphate salts have also been investigated for the capture of CO 2 , but the subsequent conversion of the captured CO 2 species is not well studied [33–36] . Metal hydroxide salts were reported as well for the capture and conversion of CO 2 [23,37] .…”