Pt monatomic wire supported on graphene nanoribbon for oxygen reduction reaction

Abstract

Among the issues inherent to fuel cells, the high cost of the Pt electrocatalyst restricts its widespread application. Controlling nano-or subnano-material structures could improve the utilization of Pt. Here, the catalytic activity of the oxygen reduction reaction (ORR) on Pt monatomic wire that is supported on the zigzag edges of graphene nanoribbon (Pt-GNR) is studied using density functional theory. It is found that Pt-GNR is inert for ORR, due to the strong binding of OH and H 2 O. However, when Pt-GNR is covered by the chain of OH and H 2 O (cPt-GNR), it becomes catalytically active for ORR. Through the free energy diagrams on cPt-GNR, we demonstrate that the highest potential U for ORR as an exothermic process is 0.82 eV. When U is larger than 0.82 V, the rate-determined step (RDS) of ORR is located at the reduction of O 2 * to OOH* (* denotes adsorbed species) where the energy barrier DG is less than 0.41 eV. These results support cPt-GNR as a candidate for ORR.

Ultrathin nanoporous metal electrodes facilitate high proton conduction for low-Pt PEMFCs

“…However, the surface of nanoporous metal has a higher high-coordinated environment than that of nanoparticles [41], which will facilitate the abovementioned electrochemical reactions. Through theoretical calculations, we investigated the rate of the key element reaction of ORR and HOR [42,43] in aqueous solution. The results show that the high-coordinated environment on the surface of nanoporous metal reduces the activation energy of the reactions (Fig.…”

The New Graphene Family Materials: Synthesis and Applications in Oxygen Reduction Reaction

“…Due to their intrinsic properties, such as abundant edges, thin walls, high surface area and excellent electrical conductivity, GNRs are extremely attractive to enhance the ORR activity [110][111][112][113][114][115][116][117][118]. In Liu's group, they used longitudinal unzipping technology to produce GNRs from CNTs [110].…”

“…All of the 3D-G can offer good catalytic properties towards ORR, and moreover, the ORR activity of 3D-G increased with the increasing number of graphene layers. The applications of GNRs can also be easily extended to other metal/metal oxides [112][113][114][115]118]. For example, combining GNRs with nanoparticles to form a hybrid is conceivable to integrate their respective merits and enhance their catalytic activity.…”

Computational chemistry for graphene-based energy applications: progress and challenges

“…Imposing strain on the graphene was found to lower the barrier of the rate-determining step in this process. As a recent and different way of approaching this problem, Xiao et al 167 explored the catalytic behaviour of a Pt nanowire adsorbed along the edge of a graphene nanoribbon substrate (see Fig 8). Building on an earlier study 166 , and using periodic PBE calculations, the authors calculated the free energy of binding of key ORR intermediates at the nanowire, indicating the viability of this substrate configuration.…”