scholarly journals Ambient nitrogen reduction cycle using a hybrid inorganic–biological system

2017 ◽  
Vol 114 (25) ◽  
pp. 6450-6455 ◽  
Author(s):  
Chong Liu ◽  
Kelsey K. Sakimoto ◽  
Brendan C. Colón ◽  
Pamela A. Silver ◽  
Daniel G. Nocera

We demonstrate the synthesis of NH3 from N2 and H2O at ambient conditions in a single reactor by coupling hydrogen generation from catalytic water splitting to a H2-oxidizing bacterium Xanthobacter autotrophicus, which performs N2 and CO2 reduction to solid biomass. Living cells of X. autotrophicus may be directly applied as a biofertilizer to improve growth of radishes, a model crop plant, by up to ∼1,440% in terms of storage root mass. The NH3 generated from nitrogenase (N2ase) in X. autotrophicus can be diverted from biomass formation to an extracellular ammonia production with the addition of a glutamate synthetase inhibitor. The N2 reduction reaction proceeds at a low driving force with a turnover number of 9 × 109 cell–1 and turnover frequency of 1.9 × 104 s–1⋅cell–1 without the use of sacrificial chemical reagents or carbon feedstocks other than CO2. This approach can be powered by renewable electricity, enabling the sustainable and selective production of ammonia and biofertilizers in a distributed manner.

2019 ◽  
Author(s):  
Anku Guha ◽  
Sreekanth Narayanru ◽  
Nisheal M. Kaley ◽  
D. Krishna Rao ◽  
Jagannath Mondal ◽  
...  

<p>Development of methods for economically feasible greener ammonia (NH<sub>3</sub>) production is gaining tremendous scientific attention. NH<sub>3</sub> has its importance in fertilizer industry and it is envisaged as a safer liquid hydrogen carrier for futuristic energy resources. Here, an aqueous electrolysis based NH<sub>3</sub> production in ambient conditions is reported, which yields high faradaic efficiency (~12%) NH<sub>3 </sub><i>via</i> nitrogen reduction reaction (NRR) at lower over potentials (~ -0.6V <i>vs.</i> RHE or -1.1V <i>vs.</i> Ag/AgCl). Polycrystalline copper (Cu) and gold (Au) are used as electrodes for electrochemical NRR, where the electrolyte which yields high amount of NH<sub>3 </sub>(~41 µmol/L) is 5M LiClO<sub>4</sub> in water with Cu as working electrode. A detailed study conducted here establishes the role of Li<sup>+</sup> in stabilizing nitrogen near to the working electrode - augmenting the NRR in comparison to its competitor - hydrogen evolution reaction, and a mechanistic insight in to the phenomenon is provided. <sup>15</sup>N<sub>2</sub> assisted labeling experiments are also conducted to confirm the formation of ammonia <i>via</i> NRR. This study opens up the possibilities of developing economically feasible electrodes for electrochemical NRR at lower energies with only transient modifications of electrodes during the electrolysis, unlike the studies reported on complex electrodes or electrolytes designed for NRR in aqueous medium to suppress the hydrogen generation. </p>


2019 ◽  
Author(s):  
Anku Guha ◽  
Sreekanth Narayanru ◽  
Nisheal M. Kaley ◽  
D. Krishna Rao ◽  
Jagannath Mondal ◽  
...  

<p>Development of methods for economically feasible greener ammonia (NH<sub>3</sub>) production is gaining tremendous scientific attention. NH<sub>3</sub> has its importance in fertilizer industry and it is envisaged as a safer liquid hydrogen carrier for futuristic energy resources. Here, an aqueous electrolysis based NH<sub>3</sub> production in ambient conditions is reported, which yields high faradaic efficiency (~12%) NH<sub>3 </sub><i>via</i> nitrogen reduction reaction (NRR) at lower over potentials (~ -0.6V <i>vs.</i> RHE or -1.1V <i>vs.</i> Ag/AgCl). Polycrystalline copper (Cu) and gold (Au) are used as electrodes for electrochemical NRR, where the electrolyte which yields high amount of NH<sub>3 </sub>(~41 µmol/L) is 5M LiClO<sub>4</sub> in water with Cu as working electrode. A detailed study conducted here establishes the role of Li<sup>+</sup> in stabilizing nitrogen near to the working electrode - augmenting the NRR in comparison to its competitor - hydrogen evolution reaction, and a mechanistic insight in to the phenomenon is provided. <sup>15</sup>N<sub>2</sub> assisted labeling experiments are also conducted to confirm the formation of ammonia <i>via</i> NRR. This study opens up the possibilities of developing economically feasible electrodes for electrochemical NRR at lower energies with only transient modifications of electrodes during the electrolysis, unlike the studies reported on complex electrodes or electrolytes designed for NRR in aqueous medium to suppress the hydrogen generation. </p>


Author(s):  
Yongwen Ren ◽  
Chang Yu ◽  
Xuedan Song ◽  
Fengyi Zhou ◽  
Xinyi Tan ◽  
...  

Electrocatalytic N2 reduction reaction (NRR) to ammonia (NH3) driven by intermittent renewable electricity under ambient conditions offers an alternative to the energy-intensive Haber−Bosch process. However, as a distinct core of...


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Limin Wu ◽  
Weiwei Guo ◽  
Xiaofu Sun ◽  
Buxing Han

Abstract Ammonia (NH3) is one of the key commercial chemicals and carbon-free energy carriers. It is mainly made by Haber-Bosch process under high temperature and high pressure, which consumes huge amount of energy and releases large amounts of CO2. Developing sustainable approaches to its production is of great importance. Powered by a renewable electricity source, electrochemical N2 reduction reaction (NRR) and nitrate reduction reaction (NITRR) are potential routes to synthesize NH3 under ambient conditions. This review summarizes major recent advances in the NRR and NITRR, especially for several years. Some fundamentals for NRR and NITRR are first introduced. Afterward, the design strategies of nanocatalysts are discussed, mainly focusing on nano-structure construction/nanoconfinement, doping/defects engineering and single-atom engineering. Finally, the critical challenges remaining in this research area and promising directions for future research are discussed.


2019 ◽  
Author(s):  
Du Sun ◽  
yunfei wang ◽  
Kenneth Livi ◽  
chuhong wang ◽  
ruichun luo ◽  
...  

<div> <p>The synthesis of alloys with long range atomic scale ordering (ordered intermetallics) is an emerging field of nanochemistry. Ordered intermetallic nanoparticles are useful for a wide variety of applications such as catalysis, superconductors, and magnetic devices. However, the preparation of nanostructured ordered intermetallics is challenging in comparison to disordered alloys, hindering progress in materials development. We report a process for converting colloidally synthesized ordered intermetallic PdBi<sub>2</sub> to ordered intermetallic Pd<sub>3</sub>Bi nanoparticles under ambient conditions by an electrochemically induced phase transition. The low melting point of PdBi<sub>2</sub> corresponds to low vacancy formation energies which enables the facile removal of the Bi from the surface, while simultaneously enabling interdiffusion of the constituent atoms via a vacancy diffusion mechanism under ambient conditions. The resulting phase-converted ordered intermetallic Pd<sub>3</sub>Bi exhibits 11x and 3.5x higher mass activty and high methanol tolerance for the oxygen reduction reaction compared to Pt/C and Pd/C, respectively,which is the highest reported for a Pd-based catalyst, to the best of our knowledge. These results establish a key development in the synthesis of noble metal rich ordered intermetallic phases with high catalytic activity, and sets forth guidelines for the design of ordered intermetallic compounds under ambient conditions.</p> </div>


Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 974
Author(s):  
Bing Han ◽  
Haihong Meng ◽  
Fengyu Li ◽  
Jingxiang Zhao

Under the current double challenge of energy and the environment, an effective nitrogen reduction reaction (NRR) has become a very urgent need. However, the largest production of ammonia gas today is carried out by the Haber–Bosch process, which has many disadvantages, among which energy consumption and air pollution are typical. As the best alternative procedure, electrochemistry has received extensive attention. In this paper, a catalyst loaded with Fe3 clusters on the two-dimensional material C2N (Fe3@C2N) is proposed to achieve effective electrochemical NRR, and our first-principles calculations reveal that the stable Fe3@C2N exhibits excellent catalytic performance for electrochemical nitrogen fixation with a limiting potential of 0.57 eV, while also suppressing the major competing hydrogen evolution reaction. Our findings will open a new door for the development of non-precious single-cluster catalysts for effective nitrogen reduction reactions.


Author(s):  
Peiei Li ◽  
Dan Cheng ◽  
Xiaohua Zhu ◽  
Meiling Liu ◽  
Youyu Zhang

Abstract Compared with the traditional Haber-Bosch process, electrochemical N2-to-NH3 reduction affords an eco-friendly and sustainable alternative to ambient NH3 synthesis with the aid of efficient electrocatalysts. In this work, partial oxidation of MnS to obtain the MnS-Mn3O4 is proved as a promising noble-free electrocatalysts of N2to NH3 fixation at ambient conditions. When tested in 0.1 M Na2SO4, the electrochemical N2 reduction reaction performance of MnS-Mn3O4 is improved comparing with the MnS, which achieves large NH3 yield of 16.74 μg h–1 mgcat.–1 and a high Faradaic efficiency of 5.72%. It also exhibits excellent selectivity of N2-to-NH3 and strong long-term electrochemical stabil


Nanoscale ◽  
2021 ◽  
Author(s):  
Zhongyuan Guo ◽  
Lakshitha Jasin Arachchige ◽  
Siyao Qiu ◽  
Xiao Li Zhang ◽  
Yongjun Xu ◽  
...  

Photocatalytic nitrogen reduction reaction (NRR) is a promising, green route to chemically reducing N2 into NH3 under ambient conditions, correlating to the N2 fixation process of nitrogenase enzymes. To achieve...


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