Improved ethanol electrooxidation performance by shortening Pd-Ni active site distance in Pd-Ni-P nanocatalysts.
Improved ethanol electrooxidation performance by shortening Pd-Ni active site distance in Pd-Ni-P nanocatalysts.
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DOI：
10.1038/ncomms14136
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发表时间：
2017-01-10
影响因子：
16.6
通讯作者：
Wang L
中科院分区：
文献类型：
--
作者：
Chen L;Lu L;Zhu H;Chen Y;Huang Y;Li Y;Wang L
在贵金属基催化剂中加入亲氧金属是提高燃料电池电催化剂催化性能的一种新兴策略。然而，贵金属和亲氧金属活性位点之间的距离对催化性能的影响很少被研究。在此，我们报道了用于乙醇电氧化的超小（~ 5 nm） Pd-Ni-P三元纳米颗粒。通过将Pd/Ni - p异源二聚体转变为Pd - Ni - p纳米粒子，并将Ni/Pd原子比调整为1:1，缩短了Pd和Ni活性位点之间的距离，使活性提高到4.95 A / mgPd，比商业Pd/C （0.72 A / mgPd）高6.88倍。密度泛函理论计算表明，活性和稳定性的提高源于自由基OH （Ni活性位点）的产生促进了碳质毒性的氧化去除，并与邻近Pd活性位点的CH3CO自由基结合。在贵金属催化剂中掺入亲氧金属可以提高电催化性能；然而，贵金属与亲氧金属活性位点之间距离的影响尚不清楚。在此，作者制备了用于乙醇氧化的Pd-Ni - p纳米催化剂，通过缩短Pd-Ni距离来提高性能。
Incorporating oxophilic metals into noble metal-based catalysts represents an emerging strategy to improve the catalytic performance of electrocatalysts in fuel cells. However, effects of the distance between the noble metal and oxophilic metal active sites on the catalytic performance have rarely been investigated. Herein, we report on ultrasmall (∼5 nm) Pd–Ni–P ternary nanoparticles for ethanol electrooxidation. The activity is improved up to 4.95 A per mgPd, which is 6.88 times higher than commercial Pd/C (0.72 A per mgPd), by shortening the distance between Pd and Ni active sites, achieved through shape transformation from Pd/Ni–P heterodimers into Pd–Ni–P nanoparticles and tuning the Ni/Pd atomic ratio to 1:1. Density functional theory calculations reveal that the improved activity and stability stems from the promoted production of free OH radicals (on Ni active sites) which facilitate the oxidative removal of carbonaceous poison and combination with CH3CO radicals on adjacent Pd active sites. Incorporating oxophilic metals into noble metal catalysts can improve electrocatalytic performance; however, the influence of the distance between noble metal and oxophilic metal active site is not well understood. Here the authors make Pd–Ni–P nanocatalysts for ethanol oxidation, with improved performance achieved by shortening the Pd–Ni distance.