Syngas conversion catalyzed by copper-embedded graphene

Mechanistic exploration of syngas conversion at the interface of graphene/Cu(111): identifying the effect of promoted electron transfer on the product selectivity

“…The Cu/graphene catalyst, owing to the coexistence of Cu and C components, exhibits remarkable catalytic activity in forming the key intermediate CH 3 and promoting carbon chain growth. 15 Our experimental results consistently demonstrate that the mesoporous carbon-supported Cu-based catalyst exhibits excellent performance in converting syngas into higher alcohols. 16 The confinement effect of the graphene–metal interface impacts the substrate adsorption and intermediate stability, leading to a reduced reaction barrier that promotes catalytic reactions.…”

“…Therefore, CO is more easily activated by indirect dissociation, and the main product of CO hydrogenation activation is CHO at the interface of graphene/Cu(111), which is consistent with that observed on Cu(111) 50,51 and Cu 1 /graphene catalysts. 15,53 Along with the initial activation, CO migrates from the hcp Cu site to the fcc Cu site and forms the stable CHO intermediate. It can be observed that the unique confined environment between the 2D graphene cover and Cu(111) surface hardly influences CO activation during syngas conversion.…”

“…Therefore, CH 3 CHO is proven to be the most competitive product over CH 4 at the interface of graphene/Cu(111), which is in line with the results of syngas conversion on Cu 1 /graphene surfaces. 15,54 In stark contrast to graphene/Cu(111), CH 3 CHO has been identified as the most favorable product in the subsequent reaction of the CH 3 intermediate over the Cu(111) surface, 52 and CH 4 becomes the most competitive product of CH 3 CHO. Therefore, the comparison between graphene/Cu(111) and Cu(111) suggests that the interaction between graphene and Cu(111) can regulate the product distribution of syngas conversion over Cu-based catalysts.…”

“…Compared with the Cu 1 /graphene catalyst, the confinement of the interface between graphene and the Cu(111) surface remarkably promoted the formation of C 2 H 5 OH, because it needs to conquer a barrier as high as 1.60 eV over the Cu 1 /graphene catalyst. 15,54…”

“…The corresponding energy barrier of 0.59 eV needs to be overcome, and the reaction energy is −0.04 eV. The formed CH 4 can easily 15,54 Besides, the generated O species by breaking the C-O bond during syngas conversion could bond with CO or OH to produce CO 2 or H 2 O, therefore we also calculated their related activation barriers and reaction energies and listed them in Table 1. CO 2 will be generated by the elementary reaction between CO and O with a 0.66 eV activation barrier and a −0.34 eV reaction energy, and the O species is most likely to come from CH 2 O + H → CH 3 + O (R19).…”