The changeable structure of 2 D graphene nanosheets makes the Pt-based nanoparticles（NPs） possess a low efficiency toward oxygen reduction reaction（ORR） and a short lifetime for proton exchange membrane fuel cells...The changeable structure of 2 D graphene nanosheets makes the Pt-based nanoparticles（NPs） possess a low efficiency toward oxygen reduction reaction（ORR） and a short lifetime for proton exchange membrane fuel cells. Thus, a unique Ti C@graphene core-shell structure material with low surface energy is designed and prepared by an in situ forming strategy, and firstly applied as a stable support of Pt NPs.The as-prepared Pt/GNS@Ti C catalyst presents a high activity. Especially, its ORR stability is remarkably improved. Even after 15000 potential cycles, the half-wave potential and mass activity toward ORR have almost no change. This can be attributed to that the graphene nanosheet existing in a sphere shape effectively avoids the restacking or folding caused by the giant surface tension in 2 D graphene nanosheets,impeding the decrease of the triple-phase boundary on Pt NPs. Significantly, the power density of fuel cells with our novel catalyst reaches 853 m V cmunder a low Pt loading(0.25 mg Pt cm) and H/Air conditions. These indicate the new ceramic@graphene core-shell nanocomposite is a promising application in fuel cells and other fields.展开更多
基金supported by the National Science Foundation of China(nos.51372186 and 51672204)
文摘The changeable structure of 2 D graphene nanosheets makes the Pt-based nanoparticles（NPs） possess a low efficiency toward oxygen reduction reaction（ORR） and a short lifetime for proton exchange membrane fuel cells. Thus, a unique Ti C@graphene core-shell structure material with low surface energy is designed and prepared by an in situ forming strategy, and firstly applied as a stable support of Pt NPs.The as-prepared Pt/GNS@Ti C catalyst presents a high activity. Especially, its ORR stability is remarkably improved. Even after 15000 potential cycles, the half-wave potential and mass activity toward ORR have almost no change. This can be attributed to that the graphene nanosheet existing in a sphere shape effectively avoids the restacking or folding caused by the giant surface tension in 2 D graphene nanosheets,impeding the decrease of the triple-phase boundary on Pt NPs. Significantly, the power density of fuel cells with our novel catalyst reaches 853 m V cmunder a low Pt loading(0.25 mg Pt cm) and H/Air conditions. These indicate the new ceramic@graphene core-shell nanocomposite is a promising application in fuel cells and other fields.
