Boron nanosheets induced microstructure and charge transfer tailoring in carbon nanofibrous mats towards highly efficient water splitting. (October 2021)

• Record Type: Journal Article
• Authors: Li, Hongling; Ren, Bohua; Liu, Wenwen; Jing, Lin; Tay, Roland Yingjie; Tsang, Siu Hon; Ricardez–Sandoval, Luis; Yu, Aiping; Teo, Edwin Hang Tong
• Is Part Of: Nano energy. Volume 88(2021)
• Publication Date: 2021-10
• Subjects: Boron carbon oxynitride nanofibrous mat -- Oxygen evolution reaction -- Hydrogen evolution reaction -- Water splitting -- DFT calculations; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2021.106246
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Development of metal-free carbon-based electrocatalysts with high-efficiency and excellent durability towards both oxygen and hydrogen evolution reactions (OER and HER) in a single electrolyte system is crucial yet challenging for sustainable energy generation. In this work, we report a facile and scalable strategy for fabricating self-supporting boron carbon oxynitride nanofibrous (BCNONF) mats with controllable boron contents via electrospinning and subsequent thermal treatment. Notably, the optimal BCNONF mat affords outstanding OER performance in alkaline electrolyte with low overpotential of 403 mV at 10 mA·cm −2, small Tafel slop of 72.9 mV·dec −1, and high stability (88.1% current density retention after 10 h), outperforming the commercial Ir/C benchmark. Moreover, it can serve as a remarkable HER catalyst with better stability than that of the commercial Pt/C counterpart in the same electrolyte, indicating its bifunctional characteristics. When employed as both anode and cathode of an electrolyzer, the self-supporting BCNONF mats exhibit superior activities with a potential of only 1.79 V at 10 mA·cm −2 and high long-term durability (90.6% current density retention after 50 h) for overall water splitting. Furthermore, density functional theory (DFT) calculations reveal that the remarkable OER and HER bifunctional performance of the BCNONF catalyst are originated from the reduced adsorption strength of O atom and the stronger H* adsorption on the BCNO surface as compared to those on CNO surface, which in turn facilitate efficient interfacial charge transfer between the electrocatalytic intermediates and the BCNONF catalyst. Graphical Abstract: ga1 Highlights: Self-supporting boron carbon oxynitride nanofibrous (BCNONF) mats were fabricated. The optimal BCNONF mat exhibited superior oxygen evolution reaction performance. The optimal BCNONF mat showed excellent hydrogen evolution reaction performance. The BCNONF mats exhibited remarkable activity and stability toward water splitting. The mechanism of enhanced electrocatalytic performance of the BCNONF was studied.