Elucidating facet dependent electronic and electrochemical properties of Cu2O nanocrystals using AFM/SCEM and DFT
Elucidating facet dependent electronic and electrochemical properties of Cu2O nanocrystals using AFM/SCEM and DFT
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使用 AFM/SCEM 和 DFT 阐明 Cu2O 纳米晶体的晶面依赖性电子和电化学特性
DOI：
10.1016/j.nantod.2022.101538
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发表时间：
2022
期刊：
影响因子：
17.4
通讯作者：
Zhang, Wen
中科院分区：
文献类型：
--
作者：
Ma, Qingquan;Young, Joshua;Basuray, Sagnik;Cheng, Guangming;Gao, Jianan;Yao, Nan;Zhang, Wen
氧化亚铜（Cu 2 O）由于其优异的光学、磁性和催化性能而被广泛研究。这些性质中的许多是取决于面的，并且还没有得到很好的阐明。本工作合成了立方，立方八面体，八面体，菱形十二面体形状的纳米Cu 2 O的尺寸约300 nm的小面依赖的电化学活性进行评估。首次采用循环伏安法（CV）和电化学阻抗谱（EIS）在系综水平上揭示了其平均电化学活性。原子力显微镜-扫描电化学显微镜（AFM-SECM）进一步用于评估不同的Cu 2 O纳米晶体的电化学活性在小平面水平。以氯化六氨合钌（{Ru（NH3）6} Cl 3）为探针分子，在400 mV的单键作用下，与四种不同的Cu 2 O纳米晶反应，在探针与纳米晶表面之间产生约300 pA的电流.尖端电流映射的结果表明，菱形十二面体的Cu 2 O表现出更高的电催化活性比其他形状的Cu 2 O，由于存在的优势暴露面的{110}所示的相对较高的尖端电流。密度泛函理论（DFT）计算证实了局域表面能和电子结构的Cu 2 O纳米晶体的面依赖性。除了电化学活性，表面功函数和吸附性能都观察到不同的形状和主要暴露面的Cu 2 O。本研究提出了一个独特的实验和计算化学方法来分析表面电化学性质的Cu 2 O晶体在晶面水平。
Cuprous oxide (Cu2O) has extensively been studied owing to its excellent optical, magnetic, and catalytic properties. Many of these properties are facet-dependent and have not been well elucidated. This work synthesized cubic, cuboctahedral, octahedral, and rhombic dodecahedral shaped Cu2O nanocrystals of ∼300 nm in size to evaluate the facet-dependent electrochemical activities. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were firstly used to reveal the average electrochemical activities at the ensemble level. Atomic force microscopy-scanning electrochemical microscopy (AFM-SECM) was further used to assess the electrochemical activities of different Cu2O nanocrystals at the facet level. Hexaammineruthenium (III) chloride ({Ru(NH3)6}Cl3) was employed as the probe molecules that reacted with four different Cu2O nanocrystals under single bond400 mV and yielded ∼300 pA current between the probing tip and the nanocrystal surface. The tip-current mapping results indicate that rhombic dodecahedral Cu2O exhibits higher electrocatalytic activity than other shaped Cu2O, due to the presence of dominant exposed facet of {110} as indicated by the relatively high tip current. Density-functional theory (DFT) calculations confirmed the facet dependence of local surface energy and electronic structure of Cu2O nanocrystals. Besides electrochemical activity, the surface work function and adsorptive properties were both observed to vary with the shape and dominant exposed facets of Cu2O. This study presented a unique experimental and computational chemistry approach to analyze surface electrochemical properties of Cu2O crystals at a crystalline facet level.