Peking University, July 11, 2016: The development of highly efficient nanocatalysts for promoting oxygen reduction reaction (ORR) is the key to improve the energy density of fuel cells and lithium air batteries. Pt is the best metal for catalyzing ORR, however its rare reserve in Nature greatly limits the commercialization of fuel cells. The density function theory calculation results reveal that the ORR intrinsic activity on PtM(M=Fe, Co, Ni) thin films follows: hollow site of high-index facet>(111)>(100). In this regards, designing PtM nanostructured materials with high-index facets is very necessary for boosting ORR. However, one of the biggest challenging issues is that high-index facets usually can happen on nanomaterials with big diameter, which exhibits the limited surface area and catalytic active center, leading to the limited mass activity for ORR.
Recently, Prof. Guo Shaojun from College of Engineering, Peking University collaborated with Prof. Huang Xiaoqing from Soochow University for developing a new Zigzag-like high-density high-index faceted CoPt nanowires (NWs) for enhancing ORR mass and specific activity based on their early work making high-index faceted PtNi NWs with relative smooth surface (Adv. Mater. 2015, 27, 7204-7212 (IF="18.90)). Compared with the PtNi work, one key feature of Zigzag-like CoPt NWs is they have much higher high-index facets, making ORR catalysis more efficient. The catalytic results show that the ORR mass activity of Zigzag CoPt NWs reaches to 4 A/mg, almost 10 times higher than that of 2018 Department of Energy target. The DFT calculation reveals that introducing high-density high-index facets onto the surface of CoPt NWs is the key for achieving very high catalytic activity. The present work opens a new way for designing highly efficient heterogeneous catalysts. This work was published in Nature Communications 2016, doi:10.1038/ncomms11850.(http://www.nature.com/ncomms/2016/160629/ncomms11850/full/ncomms11850.html.
Moreover, a Pt NWs seed mediated process was used to make new Screw Thread-like PtCu NWs through the introduction of excess Cu precursor. Due to the integrated high-index facets, they show the much enhanced electrocatalytic activity for liquid fuel oxidations. The mass activity of CuPt NWs is 6.9 and 4.8 times higher than the commercial C/Pt catalyst for methanol oxidation and ethanol oxidation reactions, respectively. This result was published in Nano Letters 2016, DOI: 10.1021/acs.nanolett.6b01825 (IF="13.592).
Prof. Guo joined College of Engineering, Peking University in Sep. 2015, and focused his research in engineering advanced nanocrystals for energy catalysis, battery and sensors. Since joining Peking U, he published more than 30 top papers related to engineering, materials and energy as the corresponding author, among which there are 15 papers published in journals of IF>10 including Nat. Commun. (1), Adv. Mater. (5), Chem. Soc. Rev. (1), Angew. Chem. (2) and Nano Lett. (2), etc.
Source: PKU News (English)
