ZnO Quantum Dots Coupled with Graphene toward Electrocatalytic N2 Reduction: Experimental and DFT Investigations

Electrochemical reduction of N2 to NH3 is a promising method for artificial N2 fixation, but it requires efficient and robust electrocatalysts to boost the N2 reduction reaction (NRR). Herein, a combination of experimental measurements and theoretical calculations revealed that a hybrid material in...

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Bibliographic Details
Published in:Chemistry : a European journal 2019-09, Vol.25 (51), p.11933-11939
Main Authors: Liu, Ya‐ping, Li, Yu‐biao, Huang, Da‐jian, Zhang, Hu, Chu, Ke
Format: Article
Language:English
Subjects:
Ammonia
Catalysis
Catalysts
Chemical reduction
Chemistry
density functional calculations
Electrocatalysts
Electrochemistry
Feasibility studies
Fixation
Graphene
Mathematical analysis
nitrogen fixation
Nitrogenation
Photovoltaic cells
Quantum dots
Sodium sulfate
Ultrafines
Zinc oxide
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Summary:Electrochemical reduction of N2 to NH3 is a promising method for artificial N2 fixation, but it requires efficient and robust electrocatalysts to boost the N2 reduction reaction (NRR). Herein, a combination of experimental measurements and theoretical calculations revealed that a hybrid material in which ZnO quantum dots (QDs) are supported on reduced graphene oxide (ZnO/RGO) is a highly active and stable catalyst for NRR under ambient conditions. Experimentally, ZnO/RGO was confirmed to favor N2 adsorption due to the largely exposed active sites of ultrafine ZnO QDs. DFT calculations disclosed that the electronic coupling of ZnO with RGO resulted in a considerably reduced activation‐energy barrier for stabilization of *N2H, which is the rate‐limiting step of the NRR. Consequently, ZnO/RGO delivered an NH3 yield of 17.7 μg h−1 mg−1 and a Faradaic efficiency of 6.4 % in 0.1 m Na2SO4 at −0.65 V (vs. RHE), which compare favorably to those of most of the reported NRR catalysts and thus demonstrate the feasibility of ZnO/RGO for electrocatalytic N2 fixation. ZnO/RGO can fix it: A hybrid material, in which ZnO quantum dots are supported on reduced graphene oxide (ZnO/RGO), was synthesized by a facile, one‐step, microwave‐assisted solvothermal method and found to be a highly active and stable catalyst for the electrochemical reduction of dinitrogen to ammonia (see figure) under ambient conditions, which is a promising method for artificial nitrogen fixation.
ISSN:0947-6539
1521-3765
DOI:10.1002/chem.201902156