Electrochemical Fragmentation of Cu2O Nanoparticles Enhancing Selective C-C Coupling from CO2 Reduction Reaction
Electrochemical Fragmentation of Cu2O Nanoparticles Enhancing Selective C-C Coupling from CO2 Reduction Reaction
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DOI：
10.1021/jacs.8b11237
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发表时间：
2019-03-20
影响因子：
15
通讯作者：
Hwang, Yun Jeong
中科院分区：
文献类型：
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作者：
Jung, Hyejin;Lee, Si Young;Hwang, Yun Jeong
在这项研究中，我们证明了纳米粒子的初始形态可以转化为小碎片的纳米粒子，这是紧密接触到对方，在电化学CO2还原反应（CO2 RR）。通过使用半胱胺固定剂，基于Cu的纳米颗粒直接生长在碳载体上，并且合成的纳米颗粒催化剂在初始CO2 RR期间显示出增加的活性，使C2 H4生产的法拉第效率从27%增加到57.3%。C2 H4生产活性的增加与反应时间内的形态转化有关。在负电位下，20 nm立方相Cu_2O晶体颗粒逐渐发生原位电化学碎裂，碎裂为2-4 nm的小颗粒，且碎裂起始于Cu_2O表面。与Cu@CuO纳米颗粒/C或块状Cu-0箔相比，碎片化Cu基NP/C催化剂实现了提高的C2+产物选择性，占总CO2 RR产物的87%，并且抑制了H-2的产生。原位X射线吸收近边结构研究表明，金属Cu状态下观察到CO2 RR，但破碎的纳米粒子更容易再氧化在电解质内的开路电位，允许不稳定的Cu状态。提出了独特的形态，小纳米颗粒堆叠在另一个上，通过抑制HER来促进来自CO2 RR的C-C偶联反应选择性。
In this study, we demonstrate that the initial morphology of nanoparticles can be transformed into small fragmented nanoparticles, which were densely contacted to each other, during electrochemical CO2 reduction reaction (CO2RR). Cu-based nanoparticles were directly grown on a carbon support by using cysteamine immobilization agent, and the synthesized nanoparticle catalyst showed increasing activity during initial CO2RR, doubling Faradaic efficiency of C2H4 production from 27% to 57.3%. The increased C2H4 production activity was related to the morphological transformation over reaction time. Twenty nm cubic Cu2O crystalline particles gradually experienced in situ electrochemical fragmentation into 2-4 nm small particles under the negative potential, and the fragmentation was found to be initiated from the surface of the nanocrystal. Compared to Cu@CuO nanoparticle/C or bulk Cu-0 foil, the fragmented Cu-based NP/C catalyst achieved enhanced C2+, production selectivity, accounting 87% of the total CO2RR products, and suppressed H-2 production. In-situ X-ray absorption near edge structure studies showed metallic Cu state was observed under CO2RR, but the fragmented nanoparticles were more readily reoxidized at open circuit potential inside of the electrolyte, allowing labile Cu states. The unique morphology, small nanoparticles stacked upon on another, is proposed to promote C-C coupling reaction selectivity from CO2RR by suppressing HER.