@article{An2021, 
author = {Chao An and Yongli Shen and Wenxiu Yan and Linxiu Dai and Changhua An},
title = {Surface-tuning nanoporous AuCu3 engineering syngas proportion by electrochemical conversion of CO2},
year = {2021},
journal = {Nano Research},
volume = {14},
number = {11},
pages = {3907-3912},
keywords = {AuCu3, surface segregation, CO2 reduction, syngas},
url = {https://www.sciopen.com/article/10.1007/s12274-021-3313-3},
doi = {10.1007/s12274-021-3313-3},
abstract = {The direct electrochemical conversion of CO2 to syngas with controllable composition remains challenging. In this work, driven by concentration gradient, a simple air-heating aided strategy has been developed to adjust surface composition of the self-supporting nanoporous AuCu3 alloy. According to Fick First Law, the interior Cu atoms of the AuCu3 alloy with Au-rich surface gradually segregated outwards during heating, realizing Cu-rich surface eventually. Correspondingly, the competing electrocatalytic CO2 reduction (ECR) to CO and hydrogen evolution reactions (HER) were tactfully balanced on these alloy surfaces, thus achieving proportion-tunable syngas (CO/H2). Density functional theory (DFT) calculations on the Gibbs free energy change of the COOH* and H* (ΔGCOOH*, ΔGH*) on the alloy surfaces were conducted, which are generally considered as the selectivity descriptors for CO and H2 products, respectively. It shows ΔGCOOH* gradually increases in contrast to the decreased ΔGH* with more Cu on the surface, suggesting H2 is more favored over Cu sites, which is consistent with the declining CO/H2 ratio observed in the experiments. This study reveals that the surface composition controls ECR activity of nanoporous AuCu3 alloy, providing an alternative way to the syngas production with desirable proportion.}
}