Effect of Additives on Ni‐Based Catalysts for Hydrogen‐Enriched Production from Steam Reforming of Biomass

Abstract

The catalytic steam reforming of biomass for hydrogen production is investigated in a fixed‐bed reactor. A suitable additive and precursor is found in various additives (cobalt, strontium, and lanthanum) and nickel salt precursors (nickel nitrate, nickel acetate, nickel chloride, and nickel sulfate). Synthesized samples are characterized by X‐ray diffraction (XRD), NH3 temperature‐programmed desorption (TPD), H2 temperature‐programmed reduction (TPR), and transmission electron microscopy (TEM). Results show that Co and La doping of the Ni/Al2O3 catalyst improves the dispersion of surface‐active particles and reduces the particle size, increasing H2 production. The hydrogen volume fraction of La‐modified catalysts with 10% Ni is 38.96%, which is higher than 30.39% for the unmodified Ni/Al2O3 catalyst. The lowest hydrogen yield of Ni–Sr/Al2O3 catalyst is 19.22%. This low catalytic activity is due to the reaction of Ni–Sr/Al2O3 with SiO2 found in biomass ash, which generates silicate without catalytic effect. The silicate melts and adheres to the catalyst surface at a high temperature, inhibiting the catalysis of nickel active sites. The maximum hydrogen yield obtained with nickel acetate as catalyst precursor is 51.41%, which is due to nickel acetate decomposing and forming more NiO in the amorphous state and improving the performance of catalyst.

Stability and activity maintenance of Ni catalysts supported on La‐, Ce‐, and Mg‐promoted Al 2 O 3 and ZrO 2 for H 2 production from steam reforming of glycerol

“…Subsequently, these metal oxides were impregnated with NiO particles by the same procedure with the first‐step impregnation method above. The three‐metal mixed oxides were finally reduced in an H 2 flow of 50 mL/min at 650°C for 2 hours to active Ni 6,33,34 . Weight ratio of Ni: promoter metal oxide: Al 2 O 3 /ZrO 2 for each final catalyst was designed as 20:10:70.…”

“…The three-metal mixed oxides were finally reduced in an H 2 flow of 50 mL/min at 650 C for 2 hours to active Ni. 6,33,34…”

“…Therefore, considerable research has focused on screening suitable supports and promoters for Ni or modifying the catalyst preparation method, trying to overcome these obstacles. Studied carriers for active Ni mainly include single metal oxide such as Al 2 O 3, 6‐11 ZrO 2, 4,8,12 La 2 O 3, 13 CeO 2, 10,14,15 MgO, 8 CaO, 16 SiO 2, 8,10,17 composite oxides such as CeO 2 ‐Al 2 O 3, 18‐23 La 2 O 3 ‐Al 2 O 3, 6,24‐26 MgO‐Al 2 O 3, 27‐31 CaO‐Al 2 O 3, 32 La 2 O 3 ‐ZrO 2, 33,34 CeO 2 ‐ZrO 2, 35‐38 CeO 2 ‐La 2 O 3 ‐Al 2 O 3, 39 and carbon material such as CNT, 30,40,41 activated biochar, 42 and graphene oxide 43,44 . Al 2 O 3 ‐supported Ni catalysts have received the most extensive study as stated above because the porous γ‐Al 2 O 3 with high surface area is very beneficial to form highly dispersed Ni crystals over the catalyst surface, thus achieving a high level of activity for SR reaction 8,10 .…”

Targeted Intermetallic Nanocatalysts for Sustainable Biomass and CO2 Valorization

“…To date, a number of economically viable catalysts for the conversion of biomass and its derivatives have been developed. 62,63 Among them, singlemetal catalysts have been widely explored in the conversion process of biomass and its derivatives. However, the addition of a second metal can significantly improve the catalytic performance of the catalyst compared to that with a single metal.…”

“…As a natural renewable resource, biomass has attracted more and more attention. To date, a number of economically viable catalysts for the conversion of biomass and its derivatives have been developed. , Among them, single-metal catalysts have been widely explored in the conversion process of biomass and its derivatives. However, the addition of a second metal can significantly improve the catalytic performance of the catalyst compared to that with a single metal. , Therefore, in recent years, IMCs have attracted increased attention as catalysts for biomass conversion.…”