PPh₃ functionalized Rh/rGO catalyst for heterogeneous hydroformylation: Bifunctional reduction of graphene oxide by organic ligand

Designing catalyst with the combined merits of heterogeneous catalysts and homogeneous catalysts through much simple one-step preparation process is always a challenge in catalysis. In this report, organic ligand triphenylphosphine (PPh₃) is first introduced as a reducing agent to reduce graphene oxide (GO) and accomplish a reduced graphene oxide (rGO) supported metal-ligand complex catalyst simultaneously. Here, the employed PPh₃ not only acts as an effective reducing agent to reduce GO, but also as a functional group to in-situ form ligand functionalized rhodium catalyst immobilized on rGO (PPh₃-Rh/rGO). The prepared PPh₃-Rh/rGO catalyst, as a heterogeneous catalyst, is applied in 1-olefins hydroformylation to form normal aldehyde, exhibiting remarkable catalytic activity and selectivity compared with other heterogeneous catalysts. It affords aldehydes in higher yields with better regioselectivity on linear products than those of other two reference catalysts reduced by ethylene glycol and hydrazine hydrate. More importantly, this efficient and simple method for preparing ligand modified metal complex catalyst supported on rGO is scalable. The great varieties of organic ligands can be chosen to extend the synthetic strategy for preparing rGO supported metal-ligand complex catalysts for various reactions.