Chang Hyuck Choi, Minho Kim, Han Chang Kwon, Sung June Cho, Seongho Yun, Hee-Tak Kim, Karl J.J. Mayrhofer, Hyungjun Kim, Minkee Choi

Nature Communications, Vol. 7, page 10922 (March 8, 2016)

[Abstract] 

Maximum atom efficiency as well as distinct chemoselectivity is expected for electrocatalysis on atomically dispersed (or single-site) metal centers, but its realization remains challenging so far because carbon as the most widely used electrocatalyst support cannot effectively stabilize them. Here we report that a sulfur-doped zeolite-templated carbon, simultaneously exhibiting extra-large sulfur content (17 wt% S) as well as a unique carbon structure (i.e., highly curved 3-dimensional networks of graphene nanoribbons), can stabilize a relatively high loading of Pt (5 wt%) in the form of atomically dispersed platinum species. In the oxygen reduction reaction (ORR), this catalyst does not follow a conventional 4-electron pathway producing H₂O, but selectively produces H₂O₂ even over extended times without significant degradation of the activity. Thus this approach constitutes a potentially promising route for producing important fine chemical H₂O₂, and also offers new opportunities for tuning selectivity of other electrochemical reactions on various metal catalysts. 

그림1. 백금 단일원자 촉매에서의 과산화수소(H₂O₂)  생성반응 모식도

 그림 2. HAADF-STEM 분석법을 통해 관찰한 백금 단일 원자 사진(탄소: gray, 수소: white, 황 : yellow, 백금 : purple)