Boosting catalytic activity of niobium/tantalum-nitrogen active-sites for triiodide reduction in photovoltaics

• Published in: Journal of colloid and interface science 2021-12, Vol.603, p.651-665
• Main Authors: Wang, Xi, Yun, Sining, Zhang, Yongwei, Zhang, Lishan, Dang, Jiaoe, Sun, Menglong, Liu, Zhuolei, Wang, Yinhao
• Format: Article
• Language: English
• Subjects: Bimetal co-modification; Dual-active sites; Hydrogen evolution reaction; Photovoltaics; Triiodide reduction reaction
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2021.06.128

[Display omitted] •Nb/Ta modified NOC was synthesized via simple pyrolysis and ion exchange.•Nb/Ta-NOC with powerful dual-active sites has worthy bifunctional catalytic ability.•Nb/Ta-NOC as electrode for IRR in solar cell showed a conversion efficiency of 8.45%.•Performance of Nb/Ta-NOC for HER is close to that of Pt/C.•Nb/Ta-NOC shows superior electrocatalytic stability in IRR and HER. To fabricate high-quality catalysts with abundant active sites, a series of transition-metal-modified nitrogenous carbon catalysts (Ta-NOC, Nb-NOC, and Nb/Ta-NOC) was successfully fabricated via pyrolysis and ion exchange. Owing to the high conductivity and ion transport capacity of its unique nitrogen-carbon structure, and synergistic effect of dual-metal active sites on modulating electronic structure, Nb/Ta-NOC catalyst exhibited an excellent catalytic performance and a remarkable electrochemical stability in triiodide reduction reaction (IRR) and hydrogen evolution reaction (HER). Nb/Ta-NOC catalyst achieved an ideal conversion efficiency of 8.45% for IRR in solar cells, which was higher than that of Pt electrode (7.63%). Furthermore, Nb/Ta-NOC catalyst exhibited a small overpotential of 145 mV at a current density of 10 mA·cm-2 and a Tafel slope of 77 mV dec-1 for HER. This work provided a new approach for the rational design of the active-sites-rich electrocatalysts for energy conversion applications.