Structural evolution of CrN nanocube electrocatalysts during nitrogen reduction reaction. Issue 37 (16th September 2020)

• Record Type: Journal Article
• Authors: Ma, Zili; Chen, Jianhong; Luo, Dongbao; Thersleff, Thomas; Dronskowski, Richard; Slabon, Adam
• Is Part Of: Nanoscale. Volume 12:Issue 37(2020)
• Page Start: 19276
• Page End: 19283
• Publication Date: 2020-09-16
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d0nr04981f
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : CrN nanocubes exhibit a gradient distribution of nitrogen and oxygen with a nitride-rich surface during electrochemical nitrogen fixation. Abstract : Metal nitrides have been suggested as prospective catalysts for the electrochemical nitrogen reduction reaction (NRR) in order to obtain ammonia at room temperature under ambient pressure. Herein, we report that templated chromium nitride porous microspheres built up by nanocubes (NCs) are an efficient noble-metal-free electrocatalyst for NRR. The CrN NCs catalyst exhibits both a high stability and NH3 yield of 31.11 μg h −1 mgcat. −1 with a Faradaic efficiency (FE) of 16.6% in 0.1 M HCl electrolyte. Complementary physical characterization techniques demonstrate partial oxidation of the pristine CrN NCs during reaction. Structural characterization by means of scanning transmission electron microscopy (STEM) combining electron energy loss spectrum (EELS) and energy dispersive X-ray spectroscopy (EDX) analysis reveals the NC structure to consist of an O-rich core and N-rich shell after NRR. This gradient distribution of nitrogen within the CrN NCs upon completed NRR is distinct to previously reported metal nitride NRR catalysts, because no significant loss of nitrogen occurs at the catalyst surface.