Promotional role of MgO on sorption‐enhanced steam reforming of ethanol over Ni/CaO catalysts

Abstract

This article describes the design and synthesis of MgO‐modified Ni/CaO catalysts for sorption‐enhanced steam reforming of ethanol. The results show that the introduction of MgO effectively increases the dispersion of CaO via forming MgCa(CO3)2 precursor. In the prepared MgO‐modified Ni/CaO catalysts, metallic Ni exists around MgO supported on CaO. Both 100% ethanol conversion and >96% hydrogen purity can be stabilized in 10 cycles over the catalyst containing 20 wt% MgO. The interaction between metallic Ni and MgO enhances the sintering resistance of the catalyst. More importantly, reaction pathway studies have confirmed that the formation of CaCO3 hinders the activation of H2O on the Ni/CaO catalyst surface, and thus inhibits the conversion of the reaction intermediates including HCO* and CH x*. MgO can dissociate H2O to form hydroxyl groups which participate in the conversion of the reaction intermediates, thereby the MgO‐modified Ni/CaO catalysts have better catalytic performance and carbon deposition resistance.

Effect of Supports and Promoters on the Performance of Ni‐Based Catalysts in Ethanol Steam Reforming

“…Additionally, “cheap” basic materials like Mg can also work as good promoters of Ni‐based catalysts in ESR , . They can be good candidates for application in the industry because they are very robust and available at low prices.…”

“…They can be good candidates for application in the industry because they are very robust and available at low prices. For example, the addition of MgO into Ni/CaO can increase the dispersion of CaO via forming a MgCa(CO 3 ) 2 precursor and suppresses the particle growth and sintering of metallic Ni by strengthening the metal‐support interaction . The increased dispersion of CaO and the reduced Ni sintering by the interaction of metallic Ni with MgO improve the ethanol sorption capacity and the catalytic activity (100 % ethanol conversion and > 96 % hydrogen over 20 wt % MgO).…”

“…Additionally, when developing catalysts for the industry, they should be inexpensive and have high stability. Currently, several candidates have shown a high hydrogen yield (> 95 %) at full ethanol conversion, including Ni‐Co/Al 2 O 3 , Ni/Al 2 O 3 ‐ZrO 2 , Ni‐Sr/Al 2 O 3 ‐ZrO 2 , Ni/10Mg‐ATP , and Mg‐Ni/CaO . These catalysts have been developed and tested on the pilot scale, before application in the industry.…”

CO2 capture using solid sorbents: Fundamental aspects, mechanistic insights and recent advances

“…CH4 [671]- [674], biomass [413], glycerol [448], [675]- [678] or ethanol [679]- [682]), to capture CO2 at a high efficiency for a long time, and possibly to enable redox-reactions simultaneously for a better heat integration [683]- [686]. Combining these functionalities in a single particle (bi-functional or tri-functional catalyst-sorbent [687]) would maximize the heat integration of the different sub-reactions, but the design of such multifunctional materials is challenging so that typically separated particle systems (i.e.…”

Ru–Ni bimetallic catalysts for steam reforming of xylene: effects of active metals and calcination temperature of the support

“…The incorporation of alkaline oxides such as MgO and CaO not only promotes the steam adsorption ability of the catalyst but also decreases the acidic sites on the alumina support which can catalyze the carbon formation during steam reforming reactions. 32,33 The other strategy is to modify the surface reactions by loading other oxides. La 2 O 3 was observed to enable the removal of carbon by forming oxycarbonate intermediates with CO 2 .…”