Ultrastable atomic copper nanosheets for selective electrochemical reduction of carbon dioxide
Authors: Peng Zhang
Lei Dai
Binghui Wu
Pei Wang
Pengxin Liu
Qing Qin
Chaofa Xu
Nanfeng Zheng
Mei Chen
Shiguang Mo
Ruixuan Qin
Gang Fu
Xiaojing Zhao
Chengyi Hu
Daohui Ou
Journal: Science Advances (2017)
Discipline: Multidisciplinary
Keywords: electrochemical conversion; CO2; H2O; syngas; catalysts
Affiliations: Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory for Physical Chemistry of Solid Surfaces, Engineering Research Center for Nano-Preparation Technology of Fujian Province, National Engineering Laboratory for Green Chemical Productions of Alcohols, Ethers, and Esters, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China., Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen, Fujian 361005, China., Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H4R2, Canada.

Abstract:  The electrochemical conversion of CO2 and H2O into syngas using renewably generated electricity is an attractive approach to simultaneously achieve chemical fixation of CO2 and storage of renewable energy. Developing cost-effective catalysts for selective electroreduction of CO2 into CO is essential to the practical applications of the approach. We report a simple synthetic strategy for the preparation of ultrathin Cu/Ni(OH)2 nanosheets as an excellent cost-effective catalyst for the electrochemical conversion of CO2 and H2O into tunable syngas under low overpotentials. These hybrid nanosheets with Cu(0)-enriched surface behave like noble metal nanocatalysts in both air stability and catalysis. Uniquely, Cu(0) within the nanosheets is stable against air oxidation for months because of the presence of formate on their surface. With the presence of atomically thick ultrastable Cu nanosheets, the hybrid Cu/Ni(OH)2 nanosheets display both excellent activity and selectivity in the electroreduction of CO2 to CO. At a low overpotential of 0.39 V, the nanosheets provide a current density of 4.3 mA/cm2 with a CO faradaic efficiency of 92%. No decay in the current is observed for more than 22 hours. The catalysts developed in this work are promising for building low-cost CO2 electrolyzers to produce CO. 

Retracted: No

PubPeer comments:
 Figs 3a, 5a.  AnnexinV-FITC PI double staining was used to detect the apoptosis of cells in each group . ![file] These scatterplots seem unusual, with their yolk-within-egg structure. Or perhaps they resemble comets. For comparison, Figs 5f,h of [Wang et al (2020)] display similar features. ![] , 
 Figs 1b, 2c, 4b. ![file] Is it possible for the authors to upload scans of the original gels for these eyebrow-like Western Blots? They sample the same confined region of morphology space as Figs 1b, 7a of [Yang et al (2021)] ... ![] ... and Figs 5b,d and 7b from [Tang Hu (2021)] . ![] Another feature that is common to these papers is an Acknowledgement,  We would like to acknowledge the reviewers for their helpful comments on this paper . This would be unexceptional on its own, but when combined with several other common features, it is suggestive of a common source. , 
 This article includes as Figure 1C a nanoparticle tracking analysis (NTA) panel. However, the size distribution panel has an overhang (compare with vertical blue line inserted into the figure). Overhangs or even vertical lines would be more consistent with a hand-drawn figure than a software-generated plot. ![file] The y-axis is also incorrectly labeled. NTA assigns sizes based on video tracking, not intensity. , 
 This article shares several more characteristics with others in the eyebrow family of papers identified by Hoya Camphorifolia. 1. Table 1 is  Primer sequence 2. miRNA RT: No miRNA-specific RT method. Mature miRNA could not have been amplified. 3. miRNA normalizer: Not specified in methods 4. miRNA-target alignment is non-canonical; function doubtful , 
 Fig 6b,  Observation of tumor after cell implantation in each group . ![file] The arrangement of these tumors seems to be digital rather than physical. The directions of the shadows they seemingly cast are not compatible with a single light source. ,