Enhanced electrocatalytic activity of Au@Cu core@shell nanoparticles towards CO2 reduction
Enhanced electrocatalytic activity of Au@Cu core@shell nanoparticles towards CO2 reduction
复制标题
DOI：
10.1039/c5ta06804e
复制
发表时间：
2015-01-01
影响因子：
11.9
通讯作者：
Rodriguez, P.
中科院分区：
文献类型：
--
作者：
Monzo, J.;Malewski, Y.;Rodriguez, P.
开发将二氧化碳再循环为含碳燃料的技术是可持续能源研究的主要挑战之一。目前的两个主要限制是催化剂效率低和快速失活。核-壳纳米粒子是增强具有挑战性的反应的有前途的候选者。在这项工作中，Au@Cu核壳纳米粒子具有明确的表面结构的合成和评价作为催化剂的二氧化碳在中性介质中的电化学还原。采用电化学方法、在线电化学质谱（OLEMS）和在线高效液相色谱（HPLC）对该催化剂的活化电位、产物分布和长期稳定性进行了评价。我们的研究结果表明，催化活性和选择性可以作为铜壳层厚度的函数进行调整。我们已经观察到具有7-8层铜的Au立方纳米颗粒对氢气和乙烯的形成呈现出更高的选择性;另一方面，我们观察到具有多于14层铜的Au立方纳米颗粒对氢气和甲烷的形成具有更高的选择性。还可以得出气体产物形成的趋势。随着Cu层数的增加，H-2和CH 4的生成量增加，而乙烯的生成量减少。甲酸是CO2还原过程中检测到的唯一液体物质。与气态物质类似，甲酸的形成强烈依赖于核@壳纳米颗粒上的Cu层的数量。具有7-8层Cu的Au立方纳米颗粒在高于0.8 V（相对于RHE）的电势下显示出CO2向甲酸的最大转化。所观察到的反应性和选择性的趋势与催化剂的组成，表面结构和应变/电子效应。
The development of technologies for the recycling of carbon dioxide into carbon-containing fuels is one of the major challenges in sustainable energy research. Two of the main current limitations are the poor efficiency and fast deactivation of catalysts. Core-shell nanoparticles are promising candidates for enhancing challenging reactions. In this work, Au@Cu core-shell nanoparticles with well-defined surface structures were synthesized and evaluated as catalysts for the electrochemical reduction of carbon dioxide in neutral medium. The activation potential, the product distribution and the long term durability of this catalyst were assessed by electrochemical methods, on-line electrochemical mass spectrometry (OLEMS) and on-line high performance liquid chromatography. Our results show that the catalytic activity and the selectivity can be tweaked as a function of the thickness of Cu shells. We have observed that the Au cubic nanoparticles with 7-8 layers of copper present higher selectivity towards the formation of hydrogen and ethylene; on the other hand, we observed that Au cubic nanoparticles with more than 14 layers of Cu are more selective towards the formation of hydrogen and methane. A trend in the formation of the gaseous products can be also drawn. The H-2 and CH4 formation increases with the number of Cu layers, while the formation of ethylene decreases. Formic acid was the only liquid species detected during CO2 reduction. Similar to the gaseous species, the formation of formic acid is strongly dependent on the number of Cu layers on the core@shell nanoparticles. The Au cubic nanoparticles with 7-8 layers of Cu showed the largest conversion of CO2 to formic acid at potentials higher than 0.8 V vs. RHE. The observed trends in reactivity and selectivity are linked to the catalyst composition, surface structure and strain/electronic effects.