Co and La supported on Zn-Hydrotalcite-derived material as efficient catalyst for ethanol steam reforming

Abstract

Four samples of Zn-hydrotalcite containing different amounts of Co (5, 10, 20, and 30 wt.%) have been synthesized and tested in the steam reforming of ethanol. The best results were obtained with the sample containing 20 wt.% of Co (20CoHT), with a complete conversion of ethanol and yields to hydrogen close to the equilibrium (73 mol.%). The physicochemical characterization of the samples by DRX, BET area and TPR indicates that the excellent performance exhibited by the sample containing 20 wt.% of Co is due to the higher percentage of reduced cobalt and lower crystallite size of metallic cobalt present in this sample (11 nm). Additional studies have been carried out to improve the stability of this catalytic material against deactivation by the incorporation of 1 wt.% of La. Stability studies were carried out using an industrial alcoholic waste as feed. Deactivation after 24 hours of reaction time was found lower for the catalyst containing La (20CoLaHT), confirming the positive effect of lanthanum on the catalytic stability. The results presented here show that it is possible to prepare a catalyst based on Co supported on Zn-hydrotalcite and promoted with La with improved ethanol conversion, high hydrogen selectivity, and high stability to produce hydrogen by the steam reforming of an industrial alcoholic waste without commercial value.

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

“…It is a highly efficient energy carrier (143 MJ kg -1 ) and it is mainly applied in fuel cells [3]. Green hydrogen can be produced from water electrolysis [4,5], photocatalytic methods [6,7], and from steam reforming of organic compounds such as methanol, ethanol, glycerol, acetic acid, acetol, and methane [8][9][10][11][12][13][14][15][16][17][18][19][20][21]. In the latter process, ethanol steam reforming (ESR) to produce hydrogen is a green and promising process because ethanol is a green material arising from biomass via conventional fermentation [22][23][24][25].…”

Sustainable Production of Hydrogen by Steam Reforming of Ethanol Using Cobalt Supported on Nanoporous Zeolitic Material

“…However, each catalyst induces different reaction pathways and, therefore, the selection of the suitable catalyst is a key factor in the SR of bioethanol. The studies show that the best catalytic results are exhibited by Ni and Co among the non-noble metals [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. The main problems during the catalytic steam reforming of bioethanol are: (i) sintering of active metal and catalyst poisoning by coke depositing at high temperature, and (ii) formation at moderate temperatures of undesired products such as acetaldehyde, diethyl ether, acetic acid, or ethylene.…”

“…The main problems during the catalytic steam reforming of bioethanol are: (i) sintering of active metal and catalyst poisoning by coke depositing at high temperature, and (ii) formation at moderate temperatures of undesired products such as acetaldehyde, diethyl ether, acetic acid, or ethylene. All these problems were found to be related to the physicochemical properties of the catalyst, which highly depend on: the nature of the metal active site, the preparation methods, the type of metal precursors used, the nature of metal support, the presence of additives, and the operating conditions [ 32 , 33 , 34 ]. Among them, support plays a crucial role in the preparation of highly active and selective catalysts for the steam reforming of bioethanol, since it favors the dispersion of metal in the catalyst and increases its activity through metal-support interactions [ 32 , 33 , 34 ].…”

“…All these problems were found to be related to the physicochemical properties of the catalyst, which highly depend on: the nature of the metal active site, the preparation methods, the type of metal precursors used, the nature of metal support, the presence of additives, and the operating conditions [ 32 , 33 , 34 ]. Among them, support plays a crucial role in the preparation of highly active and selective catalysts for the steam reforming of bioethanol, since it favors the dispersion of metal in the catalyst and increases its activity through metal-support interactions [ 32 , 33 , 34 ]. Specifically, it has been found that the high specific surface of the support may enhance the catalytic activity [ 16 , 35 ], and its topology and the crystal structure may affect the dispersion of the metal particles, improving their stability against sintering [ 28 , 36 ].…”

Hydrogen Production Performances via Steam Reforming over Hydrotalcite Derived Catalyst: A Sustainable Energy Production Review

“…Different factors are strongly related to the catalytic performance of HT derived materials. The performance of HT derived catalyst mostly depends on its preparation procedure [14] [15] [16] [17] [18], pore size [19], total surface area [20] [21] [22], modification [23] [24] [25] [26], types of metal constituents [18] [27] [28], composition [1] [29] [30] [31], promoters [32] [33] [34] [35], operating temperature [36]. Different metallic oxides prepared by HT precursors have shown super catalytic performance during fuel processing [5] [6] [14] [28] [36] [37] [38] [39] [40].…”