Selective electrocatalytic NH3 synthesis using Li intercalated 1T-MoS2.

A battery with high energy density, large capacity, long cyclability, safety, and flexibility is desired to not only power small electronic devices but also provide solutions to large-scale energy storage management. In this work, a hybrid battery of Zn–Ag and Zn–air (Zn–Ag/air) has been successfully fabricated in which Ag acted as an active material at the charging state and as an oxygen reduction reaction catalyst at the discharging state. In traditional zinc air batteries, Ag was used as a catalytic material only. In this work, sufficient amounts of Ag nanoparticles were covered onto stainless steel wire screen via a facile electrodeposition procedure as not only catalytic materials but also active redox materials. The rigid hybrid battery delivered two discharging plateaus at 1.5 and 1.1 V in which the higher one was attributed to reduction of Ag2O to Ag and the lower one resulted from Ag-assisted oxygen reduction reaction. The cyclability test showed that the Coulombic efficiency retained higher than 85% after 1700 cycles. Furthermore, the Zn–Ag/air hybrid battery was also able to be packed in a pouch cell and demonstrated high flexibility and rechargeable capability. Overall results indicate that the hybrid battery possesses both advantages of Zn–Ag and Zn–air batteries with improved discharging potential and enhanced storage capacity.

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Nitrate (NO3 –) reduction reaction (NtRR) is considered as a green alternative method for the conventional method of NH3 synthesis (Haber–Bosch process), which is known as a high energy consuming and large CO2 emitting process. Herein, the copper nanodendrites (Cu NDs) grown along with the {200} facet as an efficient NtRR catalyst have been successfully fabricated and investigated. It exhibited high Faradaic efficiency of 97% at low potential (−0.3 V vs RHE). Furthermore, the 15NO3 – isotope labeling method was utilized to confirm the formation of NH3. Both experimental and theoretical studies showed that NtRR on the Cu metal nanostructure is a facet dependent process. Dissociation of NO bonding is supposed to be the rate-determining step as NtRR is a spontaneously reductive and protonation process for all the different facets of Cu. Density functional theory (DFT) calculations revealed that Cu{200} and Cu{220} offer lower activation energy for dissociation of NO compared to that of Cu{111}.

is developed by Fritz Haber and Carl Bosch. [3] The process converts nitrogen (N 2 ) to ammonia (NH 3 ) by a reaction, also called nitrogen reduction reaction (NRR), with hydrogen (H 2 ) using a metal catalyst under high temperatures and pressures. The worldwide NH 3 production is about 140 million tonnes year −1 . [4] Unfortunately, Haber method has become one of the largest industrial energy consuming sources. Meanwhile, 1 ton of NH 3 is produced accompanied with 2 tonnes of CO 2 emissions. Currently, more than 1.6% of global CO 2 is emitted while ammonia is generated. [4] In addition, H 2 production and N 2 purification are also considered as energy intensive processes. Therefore, an environmentally friendly alternative synthesis process with no CO 2 emissions and low energy demand is desired.The electrochemical method assisted by earth-abundant materials has been utilized widely for the chemical energy conversion. [5] Earth-abundant metal compound catalysts, such as MoS 2 , [6] NiS 2 , [7] CoS 2 , [8] FeS 2 , [9] CoSe 2 , [10] CoP, [11] and MoP, [12] have been developed and exhibited good electrocatalytic activity for hydrogen evolution reaction (HER). Besides, MoS 2 , [13] SnS 2 , [14] carbon materials, [15] copper oxide, [16] etc., demonstrated CO 2 reduction reaction (CO 2 RR) by using electrolysis method. The Faradaic efficiency (FE) for HER and CO 2 RR electrolyzed by earth-abundant electrocatalysts can be achieved 99 and 90%, respectively. [9,17] However, the electrochemical synthesis of ammonia is still few. Therefore, the utilization of earth-abundant materials as efficient NRR active catalysts is of paramount importance. One report indicated that the maximum theoretical energy efficiency for the electrochemical reaction was estimated to be ≈45.9% if hydrogen evolution would be completely suppressed. [18] To date, however, it is still a challenge to convert N 2 and H 2 catalytically to NH 3 due to high activation energy of NN bond cleavage to form N 3− on the surface of catalysts as a rate-limiting step. [19] The ammonia synthesis through electrolytical method is still in its infancy. Most researches on electrochemical production of ammonia were based on molten salt electrolytes at high temperature and pressure. [20] Also, other researches indicated that the liquid solution, such as organic solvents, [21] ionic liquids, [22] and aqueous electrolyte [23] could be used as electrolytes for N 2 electrolysis with transition metal complexes as the electrocatalysts. Although aqueous electrolyteThe generation of ammonia, hydrogen production, and nitrogen purification are considered as energy intensive processes accompanied with large amounts of CO 2 emission. An electrochemical method assisted by photoenergy is widely utilized for the chemical energy conversion. In this work, earth-abundant iron pyrite (FeS 2 ) nanocrystals grown on carbon fiber paper (FeS 2 /CFP) are found to be an electrochemical and photoactive catalyst for nitrogen reduction reaction under ambient temperature and pressure. The electroche...