Hierarchical micro-reactor as electrodes for water splitting by metal rod tipped carbon nanocapsule self-assembly in carbonized wood

• Published in: Applied catalysis. B, Environmental Vol. 264; p. 118536
• Main Authors: Sheng, Xia, Li, Yuanyuan, Yang, Taimin, Timmer, Brian J.J., Willhammar, Tom, Cheung, Ocean, Li, Lin, Brett, Calvin J., Roth, Stephan V., Zhang, Biaobiao, Fan, Lizhou, Guo, Yaxiao, Zou, Xiaodong, Berglund, Lars, Sun, Licheng
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 05.05.2020; Elsevier BV
• Subjects: Arrays; Carbon; Carbonized wood; Catalysts; Electrochemistry; Electrodes; Engineering Science with specialization in Nanotechnology and Functional Materials; Iron compounds; Metal rod tipped carbon nanocapsules; Microfluidic electrodes; Microreactors; Nickel compounds; Oxidation; Oxygen evolution reaction; Oxygen evolution reactions; Reactors; Self-assembly; Splitting; Teknisk fysik med inriktning mot nanoteknologi och funktionella material; Water splitting; Microfluidic electrodes; Metal rod tipped carbon nanocapsules; Oxygen evolution reaction; Carbonized wood
• ISSN: 0926-3373; 1873-3883; 1873-3883
• DOI: 10.1016/j.apcatb.2019.118536

[Display omitted] •Micro-reactor electrodes are designed by nanostructural tailoring of carbonized wood.•NiFe rod tipped, N-doped graphitic carbon nanocapsule electrode arrays are self assembled.•The reactor to ensure maximum contact with the reaction in the mobile phase.•The overpotential for oxygen evolution reaction was decreased to 180 mV at 10 mA cm−2.•A current density of 10 mA cm−2 for overall water splitting at 1.49 V was achieved. Materials design of efficient electrochemical micro-reactors is challenging, although hierarchically structured, self-standing electrodes with catalyst arrays offer promise. Herein, catalyst function in compact micro-reactor electrodes is designed by nanostructural tailoring of carbonized wood for efficient water splitting. Specifically, NiFe rod tipped, N-doped graphitic carbon nanocapsule arrays are self-assembled in hierarchical wood, and the benefit of this unique presentation and its promotive effect on accessibility of the catalyst surfaces is apparent. This report also comprises the first wood based micro-reactor electrodes for electrocatalytic water oxidation demonstrating excellent performance. The overpotential for oxygen evolution reaction was as low as 180 mV for 10 mA cm−2 current density and TOFredox was high at a level of 5.8 s−1 (at 370 mV overpotential). This hierarchical electrode can also work as bifunctional catalyst (both as anodic and as cathodic electrode) for total water splitting with a cell potential of 1.49 V for 10 mA cm−2 in alkaline solution, suggestive of their potential also in other electrochemical applications.