Structural evolution of CrN nanocube electrocatalysts during nitrogen reduction reaction

Nanoscale, vol. 12, pp. 19276–19283

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.

Authors 6

1. Zili Ma Aachen Chair of Solid-State and Quantum Chemistry Institute of Inorganic Chemistry

   RWTH Aachen University · Stockholm University

   Affiliation as printed

   52056 Aachen

   Chair of Solid-State and Quantum Chemistry

   Germany

   Institute of Inorganic Chemistry

   RWTH Aachen University

   Chair of Solid-State and Quantum Chemistry, Institute of Inorganic Chemistry, RWTH Aachen University, 52056 Aachen, Germany

   Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden

2. Jianhong Chen

   Stockholm University

   Affiliation as printed

   10691 Stockholm

   Department of Materials and Environmental Chemistry

   Stockholm University

   Sweden

   Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden

3. Dong Luo Aachen Chair of Solid-State and Quantum Chemistry Institute of Inorganic Chemistry

   RWTH Aachen University · Shenzhen Polytechnic University

   Affiliation as printed

   52056 Aachen

   Chair of Solid-State and Quantum Chemistry

   Germany

   Institute of Inorganic Chemistry

   RWTH Aachen University

   Chair of Solid-State and Quantum Chemistry, Institute of Inorganic Chemistry, RWTH Aachen University, 52056 Aachen, Germany

   Hoffmann Institute of Advanced Materials, Shenzhen Polytechnic, 7098 Liuxian Boulevard, Nanshan District, Shenzhen, China

4. Thomas Thersleff

   Stockholm University

   Affiliation as printed

   10691 Stockholm

   Department of Materials and Environmental Chemistry

   Stockholm University

   Sweden

   Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden

5. Richard Dronskowski Aachen Chair of Solid-State and Quantum Chemistry Institute of Inorganic Chemistry

   RWTH Aachen University · Shenzhen Polytechnic University

   Affiliation as printed

   52056 Aachen

   Chair of Solid-State and Quantum Chemistry

   Germany

   Institute of Inorganic Chemistry

   RWTH Aachen University

   Chair of Solid-State and Quantum Chemistry, Institute of Inorganic Chemistry, RWTH Aachen University, 52056 Aachen, Germany

   Hoffmann Institute of Advanced Materials, Shenzhen Polytechnic, 7098 Liuxian Boulevard, Nanshan District, Shenzhen, China

6. Adam Slabon corresponding

   Stockholm University

   Affiliation as printed

   10691 Stockholm

   Department of Materials and Environmental Chemistry

   Stockholm University

   Sweden

   Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden