Promoting the electrochemical hydrogenation of furfural by synergistic Cu0−Cu+ active sites

Recent progress of Cu-based electrocatalysts for upgrading biomass-derived furanic compounds

“…Zou and co-workers employed CuO/Cu foam for the ECH of FF, which exhibited excellent performance with the selectivity and FE approximately 90% at −0.20 V vs. RHE. 56 The prepared CuO nanowires (NWs) were observed in an oxidation state by in situ X-ray absorption spectroscopy (XAS), which confirmed that the Cu 0 and Cu + states co-existed during ECH (Fig. 7g).…”

“…A series of control experiments proved that the Cu I /Cu 0 species were the active sites for ECH, which agrees with other reports. 56,68 Compared with bulky Cu, the nanostructured Cu exposed more active sites, which enhanced the FE of FAL and inhibited the HER process.…”

Cu/SiO2 synthesized with HKUST-1 as precursor: high ratio of Cu+/(Cu+ + Cu0) and rich oxygen defects for efficient catalytic hydrogenation of furfural to 2-methyl furan

“…The higher Cu + /(Cu + + Cu 0 ) ratio in Cu/SiO 2 -MOF might be responsible for its higher catalytic performance for FF hydrogenation to 2-MF, which would agree well with the synergy effect between Cu + and Cu 0 species reported previously. 44 In the fields of CO 2 and dimethyl oxalate hydrogenation as well as FF electrochemical hydrogenation, it has also been demonstrated that the Cu + /(Cu + + Cu 0 ) ratio and catalytic activity as well as catalytic stability are positively correlated. 31,43,44 To analyze whether oxygen vacancies were present in the Cu/SiO 2 catalysts prepared from the different methods, the in situ ESR spectra were also measured.…”

“…44 In the fields of CO 2 and dimethyl oxalate hydrogenation as well as FF electrochemical hydrogenation, it has also been demonstrated that the Cu + /(Cu + + Cu 0 ) ratio and catalytic activity as well as catalytic stability are positively correlated. 31,43,44 To analyze whether oxygen vacancies were present in the Cu/SiO 2 catalysts prepared from the different methods, the in situ ESR spectra were also measured. As shown in Fig.…”

Recent Advances in Furfural Reduction via Electro- And Photocatalysis: From Mechanism to Catalyst Design

“…Two pathways were proposed: (1) the red path indicated that FF was first captured by the Cu catalyst and then combined with H ads on the catalyst surface to form FAL and (2) the blue path indicated that FF first lost electrons and combined with water to form free activated furfural radicals, which were subsequently bound to H ads on the surface of the catalyst to form FAL or alternatively the two combined to form HFN (Figure a) . For the latter, since the furfural radicals were dissociative in solution without the adsorption by the catalyst, it could easily dimerize to form HFN and reduced the selectivity of FAL, consistent with that report by Li et al Furthermore, Zou et al used density functional theory (DFT) to elucidate the role of Cu 0 –Cu + species in an electrocatalytic reduction for the first time (Figure b–d) . The activation barriers for the first hydrogenation step of F-CH 2 O (F represents the furan ring) formation is smallest on the surface of Cu 0 –Cu + (0.28 eV), followed by Cu(111) (0.65 eV), and Cu 2 O­(111) (0.66 eV).…”