Research Article Issue
Hexagonal boron nitride nanosheet for effective ambient N2 fixation to NH3
Nano Research 2019, 12 (4): 919-924
Published: 07 March 2019

Industrial production of NH3 from N2 and H2 significantly relies on Haber-Bosch process, which suffers from high energy consume and CO2 emission. As a sustainable and environmentally-benign alternative process, electrochemical artificial N2 fixation at ambient conditions, however, is highly required efficient electrocatalysts. In this study, we demonstrate that hexagonal boron nitride nanosheet (h-BNNS) is able to electrochemically catalyze N2 to NH3. In acidic solution, h-BNNS catalyst attains a high NH3 formation rate of 22.4 μg·h-1·mg-1cat. and a high Faradic efficiency of 4.7% at -0.75 V vs. reversible hydrogen electrode, with excellent stability and durability. Density functional theory calculations reveal that unsaturated boron at the edge site can activate inert N2 molecule and significantly reduce the energy barrier for NH3 formation.

Research Article Issue
Self-supported CoMoS4 nanosheet array as an efficient catalyst for hydrogen evolution reaction at neutral pH
Nano Research 2018, 11 (4): 2024-2033
Published: 19 March 2018

Development of earth-abundant electrocatalysts, particularly for high-efficiency hydrogen evolution reaction (HER) under benign conditions, is highly desired, but still remains a serious challenge. Herein, we report a high-performance amorphous CoMoS4 nanosheet array on carbon cloth (CoMoS4 NS/CC), prepared by hydrothermal treatment of a Co(OH)F nanosheet array on a carbon cloth (Co(OH)F NS/CC) in (NH4)2MoS4 solution. As a three-dimensional HER electrode, CoMoS4 NS/CC exhibits remarkable activity in 1.0 M phosphate buffer saline (pH 7), only requiring an overpotential of 183 mV to drive a geometrical current density of 10 mA·cm–2. This overpotential is 140 mV lower than that for Co(OH)F NS/CC. Notably, this electrode also shows outstanding electrochemical durability and nearly 100% Faradaic efficiency. Density functional theory calculations suggest that CoMoS4 has a more favorable hydrogen adsorption free energy than Co(OH)F.

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