College of Chemistry, Chemical Engineering and Materials Science, Soochow University , Suzhou 215123, Jiangsu, China.
Testing & Analysis Center, Soochow University , Suzhou 215123, Jiangsu, China.
ACS Appl Mater Interfaces. 2016 Aug 17;8(32):20642-9. doi: 10.1021/acsami.6b02818. Epub 2016 Aug 4.
Pd has been considered as the possible economical substitute of rare Pt for catalyzing the liquid fuels electrooxidation reaction. However, the biggest problem of Pd nanocatalysts for alcohol oxidations is that they show the limited stability and activity, greatly impacting the development of liquid fuels-based fuel cell technology. We report herein a new solvent-induced procedure for making distinct Pd NCs with geometry tuning from Pd nanosheets, Pd tetrapods, to Pd concave tetrahedra by switching the solvent from 1-methyl-2-pyrrolidone, formamide, to acetylacetonate. The key features for the preparation of dimension-controlled Pd NCs herein are that the use of molybdenum carbonyl (Mo(CO)6) determines the exposed {111} facet in the final Pd NCs, while different solvents control the reduction kinetics to induce the growth of Pd NCs with distinct morphologies. The as-prepared distinct Pd NCs show the interesting shape-dependent electrocatalytic activities toward multiple liquid fuels electrooxidation reactions including ethylene glycol oxidation reaction, glycerol oxidation reaction, ethanol oxidation reaction, and also methanol oxidation reaction with Pd nanosheets exhibiting higher activity than all the other Pd catalysts and higher activity than the commercial Pd/C and also Pd black due to the thin character of Pd nanosheets. Most importantly, the Pd nanosheets exhibit much higher stability for multiple liquid fuels electrooxidation than all the other Pd catalysts tested. The present work gives the first example in exploring the effect of solvent in tuning the dimensions of Pd NCs, and thus optimizing the electrocatalytic performance for liquid fuels electrooxidation.
钯（Pd）被认为是催化液体燃料电氧化反应的稀有铂（Pt）的可能经济替代品。然而，用于醇氧化的 Pd 纳米催化剂最大的问题是它们的稳定性和活性有限，这极大地影响了基于液体燃料的燃料电池技术的发展。本文报道了一种新的溶剂诱导方法，通过将溶剂从 1-甲基-2-吡咯烷酮、甲酰胺转换为乙酰丙酮酸盐，可从 Pd 纳米片、Pd 四足体到 Pd 凹四面体来制备具有几何形状可调的独特 Pd NCs。在此处制备尺寸可控的 Pd NCs 的关键特征是使用六羰基钼（Mo(CO)6）决定最终 Pd NCs 中暴露的{111}面，而不同的溶剂控制还原动力学以诱导具有独特形貌的 Pd NCs 的生长。所制备的独特 Pd NCs 对多种液体燃料电氧化反应（包括乙二醇氧化反应、甘油氧化反应、乙醇氧化反应以及甲醇氧化反应）表现出有趣的形状依赖性电催化活性，其中 Pd 纳米片表现出比所有其他 Pd 催化剂更高的活性，并且比商业 Pd/C 和 Pd 黑更高的活性，这是由于 Pd 纳米片的薄特性。最重要的是，Pd 纳米片在多种液体燃料电氧化反应中表现出比所有其他测试的 Pd 催化剂更高的稳定性。本工作首次探索了溶剂在调节 Pd NCs 尺寸方面的作用，从而优化了液体燃料电氧化的电催化性能。
