An environmentally benign and catalytically efficient non-pyrophoric Ni catalyst for aqueous-phase reforming of ethylene glycol

Abstract

A non-pyrophoric Ni catalyst (NP Ni) was prepared by alkali leaching of a Ni 50 Al 50 alloy using only ~1/10 of the amount of NaOH required for the preparation of the conventional Raney Ni catalyst. Characterizations reveal that the as-prepared NP Ni catalyst can be looked at as a Ni-Al(OH) 3 composite catalyst with Ni in the metallic state and Al(OH) 3 in forms of gibbsite and bayerite. After 100 h on stream in aqueous-phase reforming (APR) of ethylene glycol, phase transformation of gibbsite and bayerite to flake-like boehmite occurred, along with the growth of Ni crystallites and partial oxidation of metallic Ni to Ni(OH) 2 . Under identical reaction conditions for APR of ethylene glycol, the NP Ni catalyst is about 40-52% more active than Raney Ni in terms of the conversion of ethylene glycol to gas products, which is attributed to the stabilizing effect of hydrated alumina on Ni crystallites. The higher selectivity toward H 2 and the lower concentration of CO in the product gas on the NP Ni catalyst are attributed to the activation of water by hydrated alumina which is beneficial to the water-gas shift reaction.

H2 production by selective decomposition of hydrous hydrazine over Raney Ni catalyst under ambient conditions

“…27 It has been reported that this remaining Al species could modify the chemisorption properties of reactant molecules. 28,29 The lower activity and selectivity on Raney Ni-40 reflects the detrimental effect of residue Ni-Al alloy, which prevents the selective activation of NAH bond. Hereafter, we focused our following study on Raney Ni-300 catalyst.…”

Progress in the aqueous-phase reforming of different biomass-derived alcohols for hydrogen production

“…Different types of catalysts were applied in the APR of ethylene glycol, including noble metal-based catalysts, such as Pt, Pd, Rh, Ru, and Ir (Liu et al, 2008;Skoplyak et al, 2009;Kim et al, 2011;, Sn modified Raney Ni , NiMgAl layered double hydroxide catalysts, Ni/Sn/Al hydrotalcite derived catalysts (Pan et al, 2012), rapidly quenched skeletal Ni (Xie et al, 2006), non-pyrophoric Ni catalysts (Zhu et al, 2008), and Co/ZnO catalysts (Chu et al, 2011).…”

Preparation of Ce-modified Raney Ni Catalysts and Their Application in Aqueous-Phase Reforming of Cellulose

“…5b. It was found that the peaks located at 73.7 and 66.9 eV, which were assigned to Al 2p level [30] and Ni 3p level [31], severely attenuated when large quantities of Ce were added. This attenuation could be ascribed to the heavy coverage by Ce as shown in the SEM characterization.…”

“…It was found that the Ce and Ni concentrations in the liquid effluent were 29 and 62 wppm, respectively, indicating that the gradual deactivation of the catalyst was partly attributed to the Ce and Ni leaching. In addition, the gradual deactivation was also likely to be ascribed to sintering [31], the interactions between catalyst and water (e.g., oxidation by water) during the reaction [38,39] and catalyst loss during the recycling of the catalyst [14].…”