Electrochemical reduction of carbon dioxide III. The role of oxide layer thickness on the performance of Sn electrode in a full electrochemical cell

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 2; no. 6; pp. 1647 - 1651
• Main Authors: Wu, Jingjie, Risalvato, Frank G., Ma, Shuguo, Zhou, Xiao-Dong
• Format: Journal Article
• Language: English
• Published: 01.01.2014
• Subjects: annealing; carbon dioxide; catalysts; electrochemistry; electrodes; formates; hydrogen production; nanoparticles; tin
• ISSN: 2050-7488; 2050-7496; 2050-7496
• DOI: 10.1039/C3TA13544F

A full electrochemical cell was employed to investigate the role of the surface oxide thickness on the activity of Sn-based electrodes for the electrochemical conversion of CO sub(2). The current density showed a negligible dependence on the thickness of the surface SnO sub(x) layer of Sn nanoparticles (100 nm), while the selectivity towards the formation of CO and formate exhibited a strong relationship with the initial SnO sub(x) thickness. Electrodes with a native SnO sub(x) layer of similar to 3.5 nm exhibited the highest Faradaic efficiency (64%) towards formate formation at -1.2 V. The Faradaic efficiency towards CO production reached a maximum (35%) for the electrode with an oxide thickness of 7.0 nm, formed by annealing the Sn nanoparticles at 180 degree C for 6 hours. The electrodes with a native SnO sub(x) layer displayed the highest overall selectivity towards CO sub(2) reduction. The decrease of the selectivity towards CO sub(2) reduction with increasing the thickness of the SnO sub(x) layer can be attributed to the enhancement of hydrogen evolution on the Sn clusters with a low-coordination number derived from the reduction of SnO sub(x). The Faradaic efficiency towards hydrogen production was observed to increase with increasing the thickness of the SnO sub(x) layer. Our results suggest the importance of the underlying surface structure on the selectivity and activity of the Sn electrode for CO sub(2) reduction and provide an insight into the development of efficient catalysts.