Improved Hydrogen Production from Sorption-Enhanced Steam Reforming of Ethanol (SESRE) Using Multifunctional Materials of Cobalt Catalyst and Mg-, Ce-, and Zr-Modified CaO Sorbents

Abstract

Hydrogen (H 2 ) was produced via sorption-enhanced steam reforming of ethanol (SESRE) over multifunctional hybrid materials made of cobalt (10 wt %) and a Ca-based sorbent modified by CeO 2 , ZrO 2 , and MgO. SESRE provides an excellent opportunity for producing pure H 2 from renewable ethanol by merging catalytic steam reforming and removal of the co-product carbon dioxide (CO 2 ) in a single process. The chosen hybrid materials were synthesized using the coprecipitation method and denoted as Co−CaO/CeO 2 (or HM1), Co−CaO/ZrO 2 (or HM2), and Co−CaO/MgO (or HM3). Their features were investigated using electron microscopy, X-ray diffraction, and CO 2 -temperature-programmed desorption. Their sorption capacity and adsorption breakthrough time were determined. All of the chosen materials performed remarkably well and improved H 2 production. Especially, hybrid materials containing cerium (HM1) and zirconium (HM2) displayed better adsorption capacity and extended breakthrough time than those bearing magnesium (HM3). At T = 773 K, HM1 showed the longest breakthrough time (45 min) and adsorption capacity (5.61 mol CO 2 /kg sorbent). Material HM2 demonstrated its highest breakthrough time (30 min) and adsorption capacity (3.78 mol CO 2 /kg sorbent) at T = 723 K and produced >85 mol % H 2 . HM3 displayed the highest breakthrough time (15 min) and adsorption capacity (1.51 mol CO 2 /kg sorbent) at T = 773 K, producing >75 mol % H 2 . The effects of reaction temperature, steam-tocarbon ratio in the feed, and gas hourly space velocity on the SESRE process were investigated. The performance of HM1, HM2, and HM3 was assessed over 20 cycles, and it was found that they were stable for up to 13, 10, and 5 cycles. Finally, probable reaction pathways for SESRE were discussed.

Effects of the addition of CeO2 on the steam reforming of ethanol using novel carbon-Al2O3 and carbon-ZrO2 composite-supported Co catalysts

“…As reported in the literature, 28 when recycling was repeated, deactivation was observed. Although the recycling experiments are not reported in the present study, the change in the inlet pressure with increasing temperature as shown in Table S1 † could be referred to in order to predict the reactivity for this type of catalyst.…”

“…However, the water gas shift reaction is often proposed to form carbon dioxide in SRE. 28 C–C bond cleavage of acetaldehyde on a metal site was also proposed in SRE. 26,28,33,40 Further, the steam reforming of acetone was stated in SRE.…”

“… 16 The effect of the addition of Co species to Ni/Al 2 O 3 was confirmed in oxidative SRE where Ni and Co oxides on alumina were reduced at the lower temperature and led to more stable activity and yield of hydrogen. 17 As other catalysts, Co/ZnO–Al 2 O 3 , 18 Co/CeO 2 , 19–21 Co/ZrO 2 , 19,21 Rh/Co/CeO 2 or Al 2 O 3 , 22 K/Co/Al 2 O 3 , 23,24 Co/CaO–Al 2 O 3 , 25 Cu promoted Ni–Co/hydrotalcite 26 for SRE, Co/Al 2 O 3 and Co/CeO 2 Al 2 O 3 for oxidative SRE, 27 and Co–CaO/CeO 2 , ZrO 2 and MgO, 28 CaO–Ni/Al 2 O 3 (ref. 29 ) for sorption enhanced SRE have been reported to have superior activity and selectivity.…”

Detection of Hydrogen Dissolved in Liquid Media: A Review and Outlook

“…[6][7][8] Specifically, steam reforming is the predominant process responsible for 48% of global H 2 production. [9,10] It may be combined with a catalytic partial oxidation process. This is known as an autothermal process, which yields lower amounts of hydrogen but uses less energy.…”

Ethanol Steam Reforming for Hydrogen Production Over Hierarchical Macroporous Mesoporous SBA-15 Supported Nickel Nanoparticles

“…Alkali metal or alkali earth metal promotors switch-off ethanol dehydration and ethylene polymerisation, through tuning of the acid/base nature [7], in contrast acidic supports, such as zeolites, enhance ethanol dehydration the formation of ethylene increase coking and deactivation [6]. Basic oxides of Ca and Mg have been used to increase H 2 production performance via sorptionenhance steam reforming [8,9], praseodymium and barium oxides have also promoted enhance steam reforming activity through reduced Ni sintering [10,11], whereas rare earth and transition metal oxides, e.g. CeO 2 or ZrO 2 , impart labile surface oxygen which assists oxidation of carbon deposits to CO 2 [12].…”