scholarly journals Ti2N nitride MXene evokes the Mars-van Krevelen mechanism to achieve high selectivity for nitrogen reduction reaction

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Denis Johnson ◽  
Brock Hunter ◽  
Jevaun Christie ◽  
Cullan King ◽  
Eric Kelley ◽  
...  

AbstractWe address the low selectivity problem faced by the electrochemical nitrogen (N2) reduction reaction (NRR) to ammonia (NH3) by exploiting the Mars-van Krevelen (MvK) mechanism on two-dimensional (2D) Ti2N nitride MXene. NRR technology is a viable alternative to reducing the energy and greenhouse gas emission footprint from NH3 production. Most NRR catalysts operate by using an associative or dissociative mechanism, during which the NRR competes with the hydrogen evolution reaction (HER), resulting in low selectivity. The MvK mechanism reduces this competition by eliminating the adsorption and dissociation processes at the sites for NH3 synthesis. We show that the new class of 2D materials, nitride MXenes, evoke the MvK mechanism to achieve the highest Faradaic efficiency (FE) towards NH3 reported for any pristine transition metal-based catalyst—19.85% with a yield of 11.33 μg/cm2/hr at an applied potential of − 250 mV versus RHE. These results can be expanded to a broad class of systems evoking the MvK mechanism and constitute the foundation of NRR technology based on MXenes.

Author(s):  
Peiyuan Du ◽  
Yu Hong Huang ◽  
Gangqiang Zhu ◽  
Fei Ma ◽  
Jian-Min Zhang ◽  
...  

The traditional Haber-Bosch method of ammonia (NH3) synthesis has low production efficiency and can lead to greenhouse gas emission due to high temperature and pressure dependent reactions. Hence, the nitrogen...


2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Yang Fu ◽  
Peter Richardson ◽  
Kangkang Li ◽  
Hai Yu ◽  
Bing Yu ◽  
...  

AbstractAchieving more meaningful N2 conversion by reducing the energy input and carbon footprint is now being investigated through a method of N2 fixation instead of the Haber–Bosch process. Unfortunately, the electrochemical N2 reduction reaction (NRR) method as a rising approach currently still shows low selectivity (Faradaic efficiency < 10%) and high-energy consumption [applied potential at least − 0.2 V versus the reversible hydrogen electrode (RHE)]. Here, the role of molybdenum aluminum boride single crystals, belonging to a family of ternary transition metal aluminum borides known as MAB phases, is reported for the electrochemical NRR for the first time, at a low applied potential (− 0.05 V versus RHE) under ambient conditions and in alkaline media. Due to the unique nano-laminated crystal structure of the MAB phase, these inexpensive materials have been found to exhibit excellent electrocatalytic performances (NH3 yield: 9.2 µg h−1 cm−2 mg cat. −1 , Faradaic efficiency: 30.1%) at the low overpotential, and to display a high chemical stability and sustained catalytic performance. In conjunction, further mechanism studies indicate B and Al as main-group metals show a highly selective affinity to N2 due to the strong interaction between the B 2p/Al 3p band and the N 2p orbitals, while Mo exhibits specific catalytic activity toward the subsequent reduction reaction. Overall, the MAB-phase catalyst under the synergy of the elements within ternary compound can suppress the hydrogen evolution reaction and achieve enhanced NRR performance. The significance of this work is to provide a promising candidate in the future synthesis of ammonia.


2011 ◽  
Vol 12 (1) ◽  
pp. 57-77
Author(s):  
James W Lewis ◽  
Morton A Barlaz ◽  
Akhtar Tayebali ◽  
S Ranji Ranjithan

2019 ◽  
Author(s):  
Nilanjan Sengupta

Building construction sector can play a major role in reducing Greenhouse Gas emission through application of technologies aimed at reduction of use of building materials. Energy consumed during production of building materials and components plays a crucial role in creating environmental pollution. India is witnessing high growth in urban and rural housing, which needs more production of building materials. Permanent or semi-permanent type buildings which consume easily available conventional materials like brick, reinforced cement concrete etc. can be made Economic and Eco-friendly by lowering use of energy-consuming building materials through Cost-effective Construction Technologies. Buildings with Cost-effective Construction Technology can be designed within the parameters of the existing Indian Standards. Awareness generation among the users, proper technical and architectural guidance and easy availability of skilled manpower are of utmost importance for promotion of cost-effective technologies in India and to make them as the most acceptable case of sustainable building technologies both in terms of cost and environment.


Green Farming ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 696
Author(s):  
MEERA A.V. ◽  
JOHN J. ◽  
SUDHA B. ◽  
SAJEENA A. ◽  
JACOB D. ◽  
...  

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