Highly Dispersed Ni–Fe Alloy Catalysts on MgAl₂O₄ Derived from Hydrotalcite for Direct Ethanol Synthesis from Syngas

Abstract

In view of the dual active sites mechanism of direct ethanol synthesis and the excellent catalytic performance of bimetallic catalysts, a series of Ni–Fe alloy catalysts with different Ni/Fe molar ratios derived from layered double hydroxides (LDHs) precursors are synthesized. During the calcination and reduction process of LDHs precursors, the Ni–Fe alloy is obtained, and attributed to all the elements being evenly dispersed at the atomic level in the LDHs precursors; meanwhile, a strong interaction between Ni–Fe alloy and MgAl2O4 support exists. As a result, Ni–Fe alloy nanoparticles are highly dispersed on the MgAl2O4 surface. The high CO adsorption ability on the Ni–Fe alloy and synergism catalysis between Ni and Fe result in excellent catalytic activity and high selectivity to ethanol on the bimetallic Ni–Fe alloy. In addition, the strong antisintering ability and stable alloy structure bring about a good catalytic stability. This research proposes a new catalytic system for direct ethanol synthesis from syngas.

Influence of Ni on Fe and Co-Fe Based Catalysts for High-Calorific Synthetic Natural Gas

“…With increasing Ni in Fe catalysts, the bimetallic catalysts present a higher CO conversion (99.9%) compared to Fe catalysts. It was reported that Fe-Ni bimetallic catalysts not only showed a high metal dispersion but also improved reducibility [18][19][20][21][22][23][24]. This confirms that the addition of Ni to Fe catalysts could facilitate higher dispersion and enhance the reducibility (Table 1 and Figure 2).…”

“…With an increase in Ni in Fe catalysts, peaks of NiO gradually increased and an additional peak was observed at 43. [18][19][20][21][22][23][24]. Alternatively, for the 10Fe-10Ni/γ-Al 2 O 3 catalyst, peaks of NiFe 2 O 4 were observed, suggesting that a higher Ni ratio increases the interaction between Fe and Ni [18,20].…”

Dual Active Sites of Ni and FeNi3 Constructed from Layered Double Hydroxides for One-Pot Hydrogenation of Furfural to Tetrahydrofurfuryl Alcohol

“…14-0191). In addition, no diffraction peaks of metal oxides or hydroxides are detected in all precursors, indicating that the relatively pure hydrotalcites are synthesized at the optimal conditions . The peaks in the Ni/MgAl-LDH precursor are sharp and distinct.…”

“…In addition, no diffraction peaks of metal oxides or hydroxides are detected in all precursors, indicating that the relatively pure hydrotalcites are synthesized at the optimal conditions. 24 The peaks in the Ni/MgAl-LDH precursor are sharp and distinct. However, the intensity of the hydrotalcite peak decreases significantly and the half-peak width increases continuously as the Fe content increases.…”

Co–Ni Alloy Nanoparticles on La-Doped SiO2 for Direct Ethanol Synthesis from Syngas

“…Except for LaCoO 3 /SiO 2 , the size of the metallic NPs in the reacted Ni-containing catalysts decreased in some degrees compared with their reduced catalysts, and the sizes of the NPs obtained according to 2d sinθ = n λ are listed in Table S1. ICP–OES results suggested that metallic Ni would evaporate dramatically because of the formation of evaporable Ni-carbonyls under the reaction condition. − Hence, the decrease of NPs’ sizes for Ni-containing catalysts after reaction should be attributed to nickel loss. As for LaCo 0.3 Ni 0.7 O 3 /SiO 2 after stability test, similarly, the slight decrease in the size of Ni–Co alloy NPs compared with that of the corresponding reacted catalyst is ascribed to the further nickel evaporation and the loss of cobalt species, agreeing with the ICP results.…”