Plasma Activated Electrochemical Ammonia Synthesis from Nitrogen and Water

Abstract

Ammonia is an important precursor of fertilizers, as well as a potential carbon-free energy carrier. Nowadays, ammonia is synthesized via the Haber-Bosch process which is capital-and energyintensive process with an immense CO 2 footprint. Thus, alternative processes for the sustainable and decentralized ammonia production from N2 and H2O using renewable electricity are required.The key challenges for the realization of such processes are the efficient activation of the N2 bond and selectivity towards NH3. In this contribution, we report an all-electric method for sustainable ammonia production from nitrogen and water using a plasma-activated proton conducting solid oxide electrolyser. Hydrogen species produced by water oxidation over the anode are transported through the proton conducting membrane to the cathode where they react with the plasmaactivated nitrogen towards ammonia. Ammonia production rates and faradaic efficiencies up to of 26.8 nmol NH3/s/cm 2 and 88%, respectively, were achieved.H-B process, as they prevent the possibility of lowering capital costs [16], decentralization and small-scale ammonia production at the level of local communities. Moreover, the world's hydrogen, which is also a key reactant in ammonia production, is produced primarily from the steam reforming of methane, emitting huge amounts of CO2 that account for 1.6% of global emissions per year [2, 15]. Therefore, alternative technologies need to be explored for ammonia synthesis, which occur under more moderate conditions [17], require less carbon input [18], or can be powered by intermittent renewable energy sources [19].Nowadays, plasma technology has attracted a lot of attention as an alternative method of clean ammonia synthesis, including a renewable pathway that coupled this technology with other renewable energy approaches. At low temperature, plasmas are reported as one of the most efficient approaches for rupturing the triple nitrogen bond [20][21][22][23][24], which is the fundamental requirement for the ammonia synthesis. Most of the studies on plasma-assisted ammonia synthesis are based on atmospheric pressure dielectric barrier discharge plasma over various catalytic systems, with nitrogen conversion between 0.2-7.8% in N2/H2 mixtures [25][26][27][28][29][30]. There are also approaches in which plasma activation of nitrogen and water vapor (as a hydrogen source) have been investigated for ammonia synthesis offering promising results in terms of selectivity [31][32][33][34].However, there are a few studies on the synthesis of ammonia from nitrogen−hydrogen using low pressure (0.01−10 Torr) discharges [35][36][37][38][39][40]. In fact, low pressure nitrogen discharges are wellknown for efficiently producing vibrationally excited molecules that can further generate atomic nitrogen via a vibrational dissociation channel [41][42][43]. Despite the potential benefits of plasma technologies, such as localized and environmentally friendly energy storage through chemical conversion, the two most critical challenges for upscaling ...

The Effect of Plasma Activated Water on Maize (Zea mays L.) under Arsenic Stress

“…Additionally, the use of fertilizers, especially those with low quality and control, to increase the crop yield often results in the heavy metal soil contamination [5]. On the contrary, with the use of PAW or plasma activated ammonia solutions, such contamination can be avoided, as these solutions may serve as an effective source of nitrogen with nitrates (NO 3 − ) and ammonium ions (NH 4 + ) being the most important compounds for plant growth and development [6]. Further, hydrogen peroxide (H 2 O 2 ) can serve to sterilize seeds and can also enhance seed priming.…”

Emerging Electrochemical Processes to Decarbonize the Chemical Industry

“… 87 Kumari et al reported plasma-aided N 2 electroreduction that enabled a 47% increase in ammonia production in comparison with conventional electrochemical reduction. 88 Sharma reported the integration of plasma into a proton-conducting solid oxide electrolyzer and achieved a benchmark-high ammonia production rate of 964.8 μmol h –1 cm –2 with an NH 3 FE of 10%, 89 corresponding to an ammonia partial current density of 77.57 mA cm –2 . Recently, Qiao and collaborators coupled a low-temperature plasma oxidation with electrochemical reduction, demonstrating N 2 conversion to ammonia via nitrate as an intermediate.…”

Low-Temperature Plasma-Assisted Nitrogen Fixation for Corn Plant Growth and Development

“…These nitrogen derivatives are the mobile and soluble forms of nitrogen in soil, which makes them more suitable for plant uptake [19,20]. NTAPP methods could prove to be superior to existing fertilizer technology for the following reasons: (i) They operate under atmospheric conditions using sustainable energy [21,22]. (ii) In contrast to the H-B process, they do not emit any greenhouse gases [23,24].…”