Controllable Exfoliation of MOF‐Derived Van Der Waals Superstructure into Ultrathin 2D B/N Co‐Doped Porous Carbon Nanosheets: A Superior Catalyst for Ambient Ammonia Electrosynthesis

Abstract

The electrocatalytic nitrogen reduction reaction (NRR) to synthesize NH3 under ambient conditions is a promising alternative route to the conventional Haber–Bosch process, but it is still a great challenge to develop electrocatalysts’ high Faraday efficiency and ammonia yield. Herein, a facile and efficient exfoliation strategy to synthesize ultrathin 2D boron and nitrogen co‐doped porous carbon nanosheets (B/NC NS) via a metal–organic framework (MOF)‐derived van der Waals superstructure, is reported. The results of experiments and theoretical calculations show that the doping of boron and nitrogen can modulate the electronic structure of the adjacent carbon atoms; which thus, promotes the competitive adsorption of nitrogen and reduces the energy required for ammonia synthesis. The B/NC NS exhibits excellent catalytic performance and stability in electrocatalytic NRR, with a yield rate of 153.4 µg·h−1·mg−1 cat and a Faraday efficiency of 33.1%, which is better than most of the reported NRR electrocatalysts. The ammonia yield of B/NC NS can maintain 92.7% of the initial NRR activity after 48 h stability test. The authors’ controllable exfoliation strategy using MOF‐derived van der Waals superstructure can provide a new insight for the synthesis of other 2D materials.

Self‐Assembly Strategy for Constructing Porous Boron and Nitrogen Co‐Doped Carbon as an Efficient ORR Electrocatalyst toward Zinc‐Air Battery

“…As the reference catalyst CN sample also shows similar XRD diffraction peaks, which was obtained by directly calcining CB7 without Cs 2 [ closo ‐B 12 H 12 ]. Compared with CN, the peak of (002) plane of graphitic carbon has a positive shift to around 27° observed in BCN and BCN‐P materials, due to the presence of numerous vacancies or defects resulting from the substitution of carbon atoms with co‐doped B/N atoms during the high‐temperature carbonization process [25] …”

“…Compared with CN, the peak of (002) plane of graphitic carbon has a positive shift to around 27°o bserved in BCN and BCN-P materials, due to the presence of numerous vacancies or defects resulting from the substitution of carbon atoms with co-doped B/N atoms during the hightemperature carbonization process. [25] Raman measurements were used to determine the degree of defects in carbon materials. Figure 2b With the introduction of PS, the I D /I G value of BNC-P decreases from 1.248 to 1.217, potentially indicating that PS acts as a carbon source and enhances the carbon content, thereby ameliorating some of the defects and disordered structures in BCN.…”

Design of Single‐Atom Catalysts for E lectrocatalytic Nitrogen Fixation

“…The NH 3 yield and FE of ENRR have been continuously refreshed during development. [86] However, the current accurate detection of ammonia quantification is limited not only by the detection method, but also by the contamination in the system, including the feed gas, electrolyte, catalyst, and ammoniacontaining compounds present in the Nafion membrane. This contamination often results in false positives for NH 3 .…”

A Robust n‐n Heterojunction: CuN and BN Boosting for Ambient Electrocatalytic Nitrogen Reduction to Ammonia

“…Ammonia (NH 3 ) is not only a key raw material for fertilizer and N-containing chemicals, but also a promising liquid-hydrogen storage carrier, which is currently produced by the Haber-Bosch process in industry. [1][2][3] To decrease the high energy consumption and carbon emission for synthetic ammonia industry, numerous efforts have been made to develop alternative methods for NH 3 production, such as electrocatalytic nitrogen reduction reaction (eNRR) due to its mild reaction conditions and zero emission of CO 2 . [4][5][6] To initiate an efficient eNRR, the large energy barrier of NN cleavage and weak adsorption of N 2 are the main challenges, leading to the poor activation of nitrogen molecule.…”