Electrocatalytic Synthesis of Ammonia at Room Temperature and Atmospheric Pressure from Water and Nitrogen on a Carbon‐Nanotube‐Based Electrocatalyst

Abstract

Ammonia is synthesized directly from water and N at room temperature and atmospheric pressure in a flow electrochemical cell operating in gas phase (half-cell for the NH synthesis). Iron supported on carbon nanotubes (CNTs) was used as the electrocatalyst in this half-cell. A rate of ammonia formation of 2.2×10 gNH3 m h was obtained at room temperature and atmospheric pressure in a flow of N , with stable behavior for at least 60 h of reaction, under an applied potential of -2.0 V. This value is higher than the rate of ammonia formation obtained using noble metals (Ru/C) under comparable reaction conditions. Furthermore, hydrogen gas with a total Faraday efficiency as high as 95.1 % was obtained. Data also indicate that the active sites in NH electrocatalytic synthesis may be associated to specific carbon sites formed at the interface between iron particles and CNT and able to activate N , making it more reactive towards hydrogenation.

Atomically Dispersed Molybdenum Catalysts for Efficient Ambient Nitrogen Fixation

“…[1][2][3][4] From an energy-saving perspective,g reen N 2 to NH 3 fixation methods are strongly desired because the main industrial process for producing NH 3 -the Haber-Bosch process-requires extremely harsh reaction conditions (400-600 8 8C, 20-40 MPa) and causes pollution and greenhouse gas emissions. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] However,t he efficiency of the NRR suffers from ap arallel hydrogen evolution reaction (HER) in aqueous solutions on traditional NRR electrocatalysts. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] However,t he efficiency of the NRR suffers from ap arallel hydrogen evolution reaction (HER) in aqueous solutions on traditional NRR electrocatalysts.…”

“…[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] However,t he efficiency of the NRR suffers from ap arallel hydrogen evolution reaction (HER) in aqueous solutions on traditional NRR electrocatalysts. [8,[14][15][16][17][18][19][20][21][22][23][24][25][26] Of these,e lectrocatalysts based on noble metals,s uch as Au, [8,14] Ru, [15,16] and Rh, [17] show favorable activities with hollow Au nanocages exhibiting the reported highest Faradaic efficiency (FE) of 30.2 %and acorresponding NH 3 yield rate of 3.9 mgh À1 cm À2 . [8,[14][15][16][17][18][19][20][21]…”

Greatly Improving Electrochemical N2 Reduction over TiO2 Nanoparticles by Iron Doping

“…[5][6][7][8] Noble metals perform the NRR efficiently;however, their scarcity and high cost limits their application in large-scale N 2 reduction. [33] Fe compounds have been widely utilized as catalysts for artificial N 2 fixation in the Haber-Bosch [4] and electrochemical [34][35][36][37][38][39] processes.I ti st hus natural for us to explore use of Fe as ad opant for TiO 2 ,w hich has not been reported before.Herein, we report on our recent experimental results that Fe-doped TiO 2 is superior in performances for electrocatalytic N 2 reduction under ambient conditions.I n 0.5 m LiClO 4 ,t his catalyst achieves ah igh FE of 25.6 %a nd al arge NH 3 yield of 25.47 mgh À1 mg cat À1 at À0.40 Vv ersus ar eversible hydrogen electrode (RHE), outperforming pristine TiO 2 as well as all Ti-and Fe-based NRR electrocatalysts reported to date.Remarkably,the catalyst also demonstrates high electrochemical and structural stability.T he NRR mechanism on the Fe-doped TiO 2 (101) surface is further discussed using density function theory (DFT) calculations. [12][13][14][15][16][17][18][19][20][21][22][23][24] TiO 2 is highly adaptable as asemiconductor catalyst because of its long-term thermodynamic stability,n atural abundance,a nd nontoxicity.…”

Electrocatalytic Hydrogenation of N2to NH3by MnO: Experimental and Theoretical Investigations

“…[16][17][18][19][20][21] An immediate outlook for large-scale industrial applications points toward the use of systems not relying on expensive precious metals, which strongly encourages the development of non-noble-metal NRR electrocatalysts (Fe 2 O 3 -CNT, [21] PEBCD/C, [22] NPC, [23] defect-rich MoS 2 nanoflower, [24] MoS 2 /CC, [25] and Bi 4 V 2 O 11 /CeO 2 [26] ). [16][17][18][19][20][21] An immediate outlook for large-scale industrial applications points toward the use of systems not relying on expensive precious metals, which strongly encourages the development of non-noble-metal NRR electrocatalysts (Fe 2 O 3 -CNT, [21] PEBCD/C, [22] NPC, [23] defect-rich MoS 2 nanoflower, [24] MoS 2 /CC, [25] and Bi 4 V 2 O 11 /CeO 2 [26] ).…”