Thin-wall hollow Au-Cu nanostructures with high efficiency in electrochemical reduction of CO2 to CO
Thin-wall hollow Au-Cu nanostructures with high efficiency in electrochemical reduction of CO2 to CO
复制标题
薄壁空心Au-Cu纳米结构可高效电化学还原CO2为CO
DOI：
10.1039/c8qi00297e
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发表时间：
2018
影响因子：
7
通讯作者：
Ya-Wen Zhang
中科院分区：
文献类型：
--
作者：
Jun-Hao Zhou;Da-Wei Lan;Sheng-Song Yang;Yu Guo;Kun Yuan;Lin-Xiu Dai;Ya-Wen Zhang
双金属空心结构可以有效地提高贵金属在电催化剂中的利用率，但很少有研究报道双金属空心纳米复合材料在电化学还原CO2中的应用。在此，我们演示了尺寸范围为 50 nm 至 100 nm、壁厚为 4.95 ± 0.81 nm 的空心 Au-Cu 纳米颗粒的合成，通过电置换和铜与金之间的柯肯达尔效应进行有效的 CO2 还原反应 (CO2RR)。在制造过程中，金前驱体预先溶解在 TOP 中以降低 Au3+ 的还原电位，然后可以被 Cu0 还原。然后将所得空心Au-Cu NPs负载在炭黑上进行CO2RR测量，在-0.7 V（vs. RHE）下表现出最大CO FE为53.3%，非常接近Au NP/C，但空心Au-Cu NP/C的金质量电流密度要高得多。空心 Au-Cu NP/C 在 CO2RR 的长期测量中也表现出良好的稳定性。为了了解如何实现优异的催化性能，空心 Au-Cu NP/C 在 O2 和 N2 中退火。研究发现，退火后，催化剂几乎完全丧失了对CO2RR的活性，这可能是由于纳米粒子表面Cu物种的部分偏析以及随着结晶度的提高而导致表面缺陷密度的降低。因此，得出的结论是，纳米颗粒表面上更多金原子的高度分散以及更多表面缺陷位点的存在可以解释所合成的空心Au-Cu NP/C的优异CO2RR性能。
Bimetallic hollow structures can be efficiently used to improve the utilization of noble metals in electrocatalysts, but few studies have reported the application of bimetallic hollow nanocomposites for the electrochemical reduction of CO2. Herein, we demonstrated the synthesis of hollow Au–Cu nanoparticles of size ranging from 50 nm to 100 nm with a wall thickness of 4.95 ± 0.81 nm for efficient CO2 reduction reaction (CO2RR) via galvanic replacement and the Kirkendall effect between copper and gold. In the fabrication procedure, a gold precursor was pre-dissolved in TOP to lower the reduction potential of Au3+, which could then be reduced by Cu0. The obtained hollow Au–Cu NPs were then supported on carbon black for CO2RR measurement, and it exhibited a maximum CO FE of 53.3% at −0.7 V (vs. RHE), which was very close to that of Au NP/C, but the gold mass current density of hollow Au–Cu NP/C was much higher. The hollow Au–Cu NP/C also showed good stability in long-time measurements for CO2RR. To find out how the superior catalytic performance was achieved, hollow Au–Cu NP/C was then annealed in O2 and N2. It was found that after being annealed, the catalysts almost totally lost the activity towards CO2RR, which may be due to the partial segregation of Cu species on the nanoparticle surface as well as a decrease in the surface defect density with the improvement in crystallinity. Thus, it was concluded that high dispersion of more Au atoms on the nanoparticle surface together with the presence of more surface defect sites could account for the superior CO2RR performance of the as-synthesized hollow Au–Cu NP/C.