Effect of Co-Doping on Cu/CaO Catalysts for Selective Furfural Hydrogenation into Furfuryl Alcohol

Abstract

Cu/CaO catalysts with fine-tuned Co-doping for excellent catalytic performance of furfural (FAL) hydrogenation to furfuryl alcohol (FOL) were synthesized by a facile wetness impregnation method. The optimal Co1.40Cu1/CaO catalyst, with a Co to Cu mole ratio of 1.40:1, exhibited a 100% FAL conversion with a FOL yield of 98.9% at 100 °C and 20 bar H2 pressure after 4 h. As gained from catalyst characterizations, Co addition could facilitate the reducibility of the CoCu system. Metallic Cu, Co-Cu alloys, and oxide species with CaO, acting as the major active components for the reaction, were formed after reduction at 500 °C. Additionally, this combination of Co and Cu elements could result in an improvement of catalyst textures when compared with the bare CaO. Smaller catalyst particles were formed after the addition of Co into Cu species. It was found that the addition of Co to Cu on the CaO support could fine-tune the appropriate acidic and basic sites to boost the FOL yield and selectivity with suppression of undesired products. These observations could confirm that the high efficiency and selectivity are mainly attributed to the synergistic effect between the catalytically active Co-Cu species and the CaO basic sites. Additionally, the FAL conversion and FOL yield insignificantly changed throughout the third consecutive run, confirming a high stability of the developed Co1.40Cu1/CaO catalyst.

Continuous Furfural Hydrogenolysis into 2-Methylfuran and 2-Methyltetrahydrofuran over Cu/γ–Al2O3 with ReOx and WOx as Catalyst Boosters

“…As shown in the high-resolution TEM (HR-TEM) images (Figure c,g,k) and the diffraction patterns (Figure d,h,l), the d -spacing of all of the reduced catalysts reflected the presence of metallic Cu in the (111) plane, with values of 0.200–0.210 nm, confirming the formation of Cu 0 after the H 2 reduction process. These values are consistent with previous descriptions. ,, …”

“…To differentiate among Cu 0 , Cu 1+ , and Cu 2+ species (Figure b,d,f), the Cu LMM spectra were examined, and the deconvoluted peaks at binding energies of 568.1, 569.0, and 570.0 eV correspond to the Cu 0 , Cu 2+ , and Cu 1+ states, respectively. The reference binding energies align with previous deconvoluted data from XPS results. , As summarized in Table , the major fraction identified from the Cu LMM results in CuAl, ReCuAl, and WCuAl catalysts was Cu 0 , followed by the Cu 1+ and Cu 2+ states. Notably, the Cu 0 fraction appeared to be higher for the CuAl catalyst compared with ReCuAl and WCuAl catalysts.…”

“…These values are consistent with previous descriptions. 31,42,43 3.3. Catalytic Performance and Durability Test.…”

“…The reference binding energies align with previous deconvoluted data from XPS results. 9,31 As summarized in Table 3, the major fraction identified from the Cu LMM results in CuAl, ReCuAl, and WCuAl catalysts was Cu 0 , followed by the Cu 1+ and Cu 2+ states. Notably, the Cu 0 fraction appeared to be higher for the CuAl catalyst compared with ReCuAl and WCuAl catalysts.…”

Continuous flow hydrogenolysis of 5-hydroxymethylfurfural into 2,5-dimethylfuran over alumina-supported nickel–iron alloy catalysts

“…The GC conditions were adapted from earlier investigations. 27–29 The mass balance was above 95% for all the experiments. The calibration curves of 5-HMF and the main products were used to quantify the amount of remaining reactant and all the generated products.…”