Hydrothermal synthesis of graphene-LaFeO3 composite supported with Cu-Co nanocatalyst for higher alcohol synthesis from syngas

Abstract

The composite of graphene and a perovskite-type oxide (PTO) should be an attractive new material, owing to the special properties of graphene and the flexibility of PTO. Both graphene and PTO are promising support for some metallic nanoparticles. Therefore, in this work, taking LaFeO 3 as the representative for PTO, a novel composite of graphene sheets-LaFeO 3 has been prepared by using hydrothermal synthesis, and bimetallic nanoparticles of Cu-Co have been loaded on the composite. The resultant catalyst is applied to higher alcohols synthesis (HAS) from syngas. The morphology, structure and the state of the bimetallic composite catalyst are characterized by using techniques of SEM, TEM, AFM, XRD, TPR, Raman and N 2 adsorption-desorption. For the graphene-LaFeO 3 support, the graphene sheets are embedded into the bulk LaFeO 3 or uniformly deposited on the surface of the LaFeO 3 grains, resulting in high specific surface area.And the mass transferring ability of the bimetallic catalyst is optimized by uniform mixing of graphene and LaFeO 3 and the formation of the mesopores. For the active component, the Cu-Co alloy nanoparticles are highly dispersed on the graphene-LaFeO 3 composite, which leads to the high activity, high selectivity and

Mixed Oxides Confined and Tailored Cobalt Nanocatalyst for Direct Ethanol Synthesis from Syngas: A Catalyst Designing by Using Perovskite-Type Oxide as the Precursor

“…During the calcination process, the polymer decomposes and microlite of La, Sr, Co, and Ga oxide particles with uniformly dispersion forms. In higher temperature, the sintering of the microlite occurs and a solid phase reaction happens to generate PTO, during this process, the pores of the catalysts emerge and the formation of the pores can be contributed to the stacking of grains of PTOs, which is consistent with the literature. , …”

“…In higher temperature, the sintering of the microlite occurs and a solid phase reaction happens to generate PTO, during this process, the pores of the catalysts emerge and the formation of the pores can be contributed to the stacking of grains of PTOs, which is consistent with the literature. 39,40 For LCG and LSCG-x, with the increasing content of Sr, the pores sizes and pore volume become larger, the initial hysteresis loop moves to lower P/P 0 and the hysteresis loop becomes bigger. Thus, the higher BET surface area can be seen in Table 1.…”

High-Performance CoCu Catalyst Encapsulated in KIT-6 for Higher Alcohol Synthesis from Syngas

“…High dispersion and stability of active sites play an important role in enhancing catalyst activities for HAS as well. 17,19 However, for the CoCu catalyst, the alloy phase is easy to separate, causing particle aggregation and catalyst deactivation. For example, a (Cu 1 Co 2 ) 2 Al layered double hydroxide catalyst was reported to have great initial activity, but in the following 100 h, the CO conversion decreased from 61.3 to 40.6% and the selectivity to alcohols decreased from 56.8 to 51.0%.…”

“…Significant progress has been achieved in the fabrication of CoCu bimetallic catalysts, where the reported precursors mainly include CuCo 2 O 4 spinel oxides, , perovskite-structured oxides, and layered double hydroxides. − It is believed that because Co and Cu ions were closely confined in the same oxide structure, the intimate contact between them could be maintained, which would boost the selectivity of HA. High dispersion and stability of active sites play an important role in enhancing catalyst activities for HAS as well. , However, for the CoCu catalyst, the alloy phase is easy to separate, causing particle aggregation and catalyst deactivation. For example, a (Cu 1 Co 2 ) 2 Al layered double hydroxide catalyst was reported to have great initial activity, but in the following 100 h, the CO conversion decreased from 61.3 to 40.6% and the selectivity to alcohols decreased from 56.8 to 51.0%.…”

In Situ Encapsulated CuCo@M-SiO2 for Higher Alcohol Synthesis from Biomass-Derived Syngas

“…Furthermore, it has been claimed that the closer the vicinity of both Cu–Co metal species, the better the synergistic effect will be . Fortunately, the Cu–Co bimetallic catalyst can be successfully achieved from several precursors mainly including crystalline porous materials (CPMs), − layered double hydroxides (LDHs), ,,,− oxalate co-precipitation oxides, − and perovskite morphology oxides. − As a new class of promising materials, CPMs have exhibited enhanced activity, selectivity, and stability owing to synergistic catalysis. In the case of LDHs, the Cu–Co NPs exhibited excellent catalytic performance for HAS because of uniformly distributed and highly dispersed Cu–Co particles at the nano-size level, as well as they were confined into the oxide structure derived from the LDH structure .…”