Catalytic Steam Reforming of Ethanol to Produce Hydrogen: Modern and Efficient Catalyst Modification Strategies

Abstract

Hydrogen is regarded as one of the most promising renewable energy that carriers with a high heating value for replacing fossil fuels and meeting clean energy requirements. Steam reforming has shown considerable promises in the creation of hydrogen. Many studies on catalytic steam reforming of ethanol have been published. Hence, developing efficient and stable catalysts capable of producing large H2 yields and ethanol conversion is a crucial step. Nickel is an essential industrial catalyst because it enhances hydrogenation and dehydrogenation reactions by promoting the scission of C−C bonds. Many studies have been conducted by employing noble metal‐based catalysts to reduce coke deposition and enhance metal stability against sintering since they are known to successfully break the C−C bond, resulting in less carbonaceous deposits and hence more stable catalysts. To avoid carbon production, alkaline promoters, and bimetallic heterogeneous catalysts are commonly utilized in catalysis. However, because huge amounts of by‐product CO2 produced by SRE courses are usually regarded as the primary cause of hydrogen purity degradation, it is recommended to remove CO2 in‐situ to achieve high hydrogen production.

Reforming of ethanol with carbon dioxide catalysed by silver-promoted copper–ceria–zirconia composites

“…1 Ethanol is a common product, not toxic, safely preserved, transferred, treated and further could be a very attractive hydrogen source. However, DRE has not been studied as much as steam reforming [38][39][40][41][42][43][44][45][46][47][48][49][50][51] probably because the former needs relatively higher temperature and selectivity for H 2 and CO does not increase due to the ease of decomposition of ethanol into hydrocarbon fragments at higher temperature. Nevertheless, DRE has still been desired since syngas with a H 2 /CO ratio of 1 suitable for hydrocarbon production in the Fischer-Tropsch reaction could be produced.…”

Global Vision of the Reaction and Deactivation Routes in the Ethanol Steam Reforming on a Catalyst Derived from a Ni–Al Spinel

“…The most common catalysts for the ESR are based on Ni or Co supported on various oxides and less commonly based on noble metals, such as Pt or Rh. [8][9][10]19,20 Those based on Ni are preferred due to their high activity in the steps of the reforming reaction mechanism, including C−C and C−H bond cleavage, H 2 O adsorption and dissociation, and their comparatively low cost. 21,22 The problem of rapid deactivation of the Ni catalysts by sintering and coke deposition has been a topic of interest to study different preparation strategies and formulations.…”

“…The catalyst and reaction conditions are the main factors that tip the balance toward certain products by favoring selectively the extent of reactions in Table . The most common catalysts for the ESR are based on Ni or Co supported on various oxides and less commonly based on noble metals, such as Pt or Rh. − ,, Those based on Ni are preferred due to their high activity in the steps of the reforming reaction mechanism, including C–C and C–H bond cleavage, H 2 O adsorption and dissociation, and their comparatively low cost. , The problem of rapid deactivation of the Ni catalysts by sintering and coke deposition has been a topic of interest to study different preparation strategies and formulations. ,, The dehydrogenation reactions are favored on noble metals, which leave dehydrogenated surface species that are effectively oxidized to CO or CO 2 , suppressing the formation of CH 4 and carbon . Regarding the important role of the catalyst support, the properties that determine the reaction routes are its acidity/basicity/neutrality, hydrophilicity, and oxygen mobility capacity.…”