Sun Yingjun, Huang Bolong, Xu Nuoyan, Li Yingjie, Luo Mingchuan, Li Chunji, Qin Yingnan, Wang Lei, Guo Shaojun
Department of Materials Science & Engineering, College of Engineering, Peking University, Beijing 100871, China; College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong SAR, China.
Sci Bull (Beijing). 2019 Jan 15;64(1):54-62. doi: 10.1016/j.scib.2018.12.008. Epub 2018 Dec 7.
Direct methanol fuel cells (DMFCs) have received extensive attention on their high efficiency, high reliability, and no carbon emission. Unfortunately, the poor methanol tolerance and sluggish oxygen reduction reaction (ORR) at cathode have seriously hindered their further development. Herein we report the synthesis of a new class of Rh-doped PdAg alloy nanoparticles (NPs) for boosting ORR activity with high methanol tolerance capacity concurrently. The ORR mass activity of typical RhPdAg NPs is 4.2 times higher than that of commercial Pt catalyst. Moreover, it shows a great methanol tolerance capability by maintaining 92.4% in ORR mass activity in alkaline solution with 0.1 mol L methanol, against a big decrease of almost 100% for commercial Pt. Even after 30,000 potential cycles with 1.0 mol L methanol, RhPdAg NPs still retain ORR mass activity of up to 68.3%. DFT calculations reveal that excellent ORR performance with excellent methanol tolerance originates the active d-band-pinning engineering for an efficient site-independent electron-transfer. A generalized d-band mediated fine electron-transfer tuning path has blueprinted for effectively minimizing intrinsic ORR barriers with high current density. The present work highlights the key role of Rh doping in enhancing the ORR activity and methanol tolerance ability of PdAg NPs for future high-performance DMFCs.
直接甲醇燃料电池（DMFCs）因其高效率、高可靠性和无碳排放而受到广泛关注。不幸的是，其较差的甲醇耐受性以及阴极上缓慢的氧还原反应（ORR）严重阻碍了它们的进一步发展。在此，我们报道了一类新型的Rh掺杂PdAg合金纳米颗粒（NPs）的合成，该纳米颗粒可同时提高ORR活性并具有高甲醇耐受能力。典型的RhPdAg NPs的ORR质量活性比商业Pt催化剂高4.2倍。此外，在含有0.1 mol/L甲醇的碱性溶液中，它表现出很强的甲醇耐受能力，其ORR质量活性保持在92.4%，而商业Pt几乎下降了100%。即使在含有1.0 mol/L甲醇的情况下经过30000次电位循环后，RhPdAg NPs仍保留高达68.3%的ORR质量活性。密度泛函理论（DFT）计算表明，具有优异甲醇耐受性的出色ORR性能源于用于高效的与位点无关的电子转移的活性d带钉扎工程。一个广义的d带介导的精细电子转移调节路径已被设计出来，用于有效地最小化具有高电流密度的本征ORR势垒。目前的工作突出了Rh掺杂在提高PdAg NPs的ORR活性和甲醇耐受能力以用于未来高性能DMFCs方面的关键作用。
