Zheng Yulin, Zhao Shulin, Liu Suli, Yin Huanhuan, Chen Yu-Yun, Bao Jianchun, Han Min, Dai Zhihui
Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, Nanjing Normal University , Nanjing 210023, People's Republic of China.
ACS Appl Mater Interfaces. 2015 Mar 11;7(9):5347-57. doi: 10.1021/acsami.5b01541. Epub 2015 Mar 2.
Exploring low-cost, high-activity, and long-durability hybrid electrocatalysts for cathodic oxygen reduction reaction (ORR) is vital to advance fuel cells technologies. In this paper, a series of graphene (G)-CuxPdy (Cu4Pd, Cu3Pd, CuPd, CuPd3, CuPd4) nanocomposites (G-CuxPdy NCPs) is obtained by assembly of CuxPdy alloy nanocrystals (NCs) with controlled component ratios on G nanosheets using the "dispersing-mixing-vaporizing solvent" strategy and used as electrocatalysts for ORR. Compared with pure CuxPdy NCs, greatly enhanced interfacial electron transfer dynamics are observed in G-CuxPdy NCPs, which show a strong correlation with the alloy compositions of the NCPs. The electrocatalytic experiments in alkaline solution reveal that the ORR activities of those G-CuxPdy NCPs are also strongly dependent on alloy components and exhibit a double-volcano feature with variations of alloy components. Among them, G-Cu3Pd NCPs possess the highest electrocatalytic activity, which is much better than some reported electrocatalysts and commercial Pd/C catalyst and close to Pt/C catalyst. By correlating the Pd 3d binding energies and the sizes of CuxPdy NCs with the mass-specific activities of G-CuxPdy NCPs and considering the interfacial electron transfer dynamics, the best catalytic activity of G-Cu3Pd NCPs may result from the unique electronic structure and the smallest size of Cu3Pd NCs as well as the strong synergistic effect between G and Cu3Pd NCs. Moreover, the durability of G-Cu3Pd NCPs is superior to that of Pt/C catalyst, indicating that they are promising cathodic electrocatalysts for using in alkaline fuel cells.
探索用于阴极氧还原反应（ORR）的低成本、高活性和长耐久性的混合电催化剂对于推动燃料电池技术至关重要。本文采用“分散-混合-蒸发溶剂”策略，通过在石墨烯（G）纳米片上组装具有可控组分比的铜钯合金（CuₓPdᵧ，包括Cu₄Pd、Cu₃Pd、CuPd、CuPd₃、CuPd₄）纳米晶体（NCs），制备了一系列石墨烯（G）-铜钯（CuₓPdᵧ）纳米复合材料（G-CuₓPdᵧ NCPs），并将其用作ORR的电催化剂。与纯CuₓPdᵧ NCs相比，G-CuₓPdᵧ NCPs中观察到界面电子转移动力学显著增强，这与NCPs的合金组成密切相关。碱性溶液中的电催化实验表明，这些G-CuₓPdᵧ NCPs的ORR活性也强烈依赖于合金组分，并随着合金组分的变化呈现双火山特征。其中，G-Cu₃Pd NCPs具有最高的电催化活性，比一些已报道的电催化剂和商业Pd/C催化剂要好得多，接近Pt/C催化剂。通过将Pd 3d结合能和CuₓPdᵧ NCs的尺寸与G-CuₓPdᵧ NCPs的质量比活性相关联，并考虑界面电子转移动力学，G-Cu₃Pd NCPs的最佳催化活性可能源于其独特的电子结构、最小尺寸的Cu₃Pd NCs以及G与Cu₃Pd NCs之间的强协同效应。此外，G-Cu₃Pd NCPs的耐久性优于Pt/C催化剂，表明它们是用于碱性燃料电池的有前景的阴极电催化剂。
