NH3 Selectivity Research Articles

Dynamic Reconstruction of Cu Catalyst under Electrochemical NO Reduction to NH3.

The electrochemical reduction of nitric oxide (NO) to ammonia (NH3) offers a sustainable way of simultaneously treating the air pollutant and producing a useful chemical. Among catalyst candidates, Cu emerges as a stand-out choice for its superb NH3 selectivity and production rate. However, a comprehensive study concerning its catalytic behaviorin the NO reduction environment is lacking. Here, we unravel the dynamic rearrangement of Cu catalysts during NO reduction: the emergence of a bundled nanowire structure dependent on the applied potential. This unique structure is closely linked to an enhancement in double-layer capacitance, leading to a progressive increase in current density from 236 mA cm-2 by 20% over 1 h, while maintaining a Faradaic efficiency of 95% for NH3. Characterizations of Cu oxidation states suggest that the nanostructure results from the dissolution-redeposition of Cu in the aqueous electrolyte, influenced by the interaction with NO or other reactive intermediates. This understanding contributes to the broader exploration of Cu-based catalysts for sustainable and efficient NH3 synthesis from NO.

Tuned targeted catalytic engineering enables high-selective electrochemical low-concentration nitrate-to-ammonia

Electrocatalytic nitrate reduction reaction (NO3RR) is anticipated to enable utilization of NO3- from wastewater, providing a prospective solution to address global nitrogen-cycle imbalance. Nevertheless, high-selective conversion of low-concentration NO3--to-NH3 in non-alkaline environment remains challenging, stemming from kinetic retardation and hydrogen evolution reaction (HER). Herein, a targeted synergistic-cascade strategy is proven for breaking through the bottleneck. Significantly, the rationally-designed asymmetric oxygen vacancies (VO)-mediated Cu-Co dual-site catalyst achieve a NH3 selectivity of 95.79 % and a NH3-N yield of 1.528 mg h−1 cm−2 under 140 ppm NO3--N environment. The mitigation of kinetic bottlenecks is attributed to the NO3- activation capability of Cu sites and intermediate hydrogenation of Co sites on the optimized cascade catalytic system. Density functional theory (DFT) reveals that the asymmetric VO fine-tuned the electronic structure and d-band center of Cu-Co dual-sites, which synergistically reduce the energy barrier of NO3RR and alleviate the competing HER. An integrated system is constructed for the in situ conversion of NO3- to ammonium sulfate under low NO3--N concentration water body, showcasing the potential for practical application.

Bimetallic Cu11Ag3 Nanotips for Ultrahigh Yield Rate of Nitrate-to-Ammonium.

Electrochemical reduction of nitrate to ammonia (NRA) offers a sustainable approach for NH3 production and NO3- removal but suffers from low NH3 yield rate (<1.20 mmol h-1 cm-2). We present bimetallic Cu11Ag3 nanotips with tailored local environment and tip-enhanced effects, which achieve an ultrahigh NH3 yield rate of 2.36 mmol h-1 cm-2 at a low applied potential of -0.33 V vs. RHE, a high Faradic efficiency (FE) of 98.8%, and long-term operation stability at 1800 mg-N L-1 NO3-, outperforming most of the recently reported catalysts. At a NO3- concentration as low as 15 mg-N L-1, it still delivers a high FE of 86.9% and an NH3 selectivity of 93.8%. Operando ATR-FTIR spectra, finite-element method, and DFT calculations reveal that the Cu11Ag3 exhibits reduced adsorption energy barrier of *N intermediates, favorable water dissociation for *H generation and high energy barrier for H2 formation, while its tip-enhanced enrichment promoting NO3- accumulation.

Bimetallic Cu11Ag3 Nanotips for Ultrahigh Yield Rate of Nitrate‐to‐Ammonium

Electrochemical reduction of nitrate to ammonia (NRA) offers a sustainable approach for NH3 production and NO3‐ removal but suffers from low NH3 yield rate (&lt;1.20 mmol h‐1 cm‐2). We present bimetallic Cu11Ag3 nanotips with tailored local environment and tip‐enhanced effects, which achieve an ultrahigh NH3 yield rate of 2.36 mmol h‐1 cm‐2 at a low applied potential of ‐0.33 V vs. RHE, a high Faradic efficiency (FE) of 98.8%, and long‐term operation stability at 1800 mg‐N L‐1 NO3‐, outperforming most of the recently reported catalysts. At a NO3‐ concentration as low as 15 mg‐N L‐1, it still delivers a high FE of 86.9% and an NH3 selectivity of 93.8%. Operando ATR‐FTIR spectra, finite‐element method, and DFT calculations reveal that the Cu11Ag3 exhibits reduced adsorption energy barrier of *N intermediates, favorable water dissociation for *H generation and high energy barrier for H2 formation, while its tip‐enhanced enrichment promoting NO3‐ accumulation.

Phosphorization of α-Fe2O3 Boosts Active Hydrogen Mediated Electrochemical Nitrate Reduction to Ammonia.

Inexpensive iron-based materials are considered promising electrocatalysts for nitrate (NO3 -) reduction, but their catalytic activity and spontaneous corrosion remain challenges. Here, the α-Fe2O3 active surface is reconstructed by gradient phosphorization to obtain FePx with higher electrochemical activity. FeP2.0 optimizes the adsorption energy of NO3 - and its reduction intermediates, meanwhile promote the generation of active hydrogen (*H) but inhibit its generation of H2. More importantly, Fe and P can serve as binding sites for NO3 - and *H, respectively, which improves the electron utilization of NO3 - deoxygenation and the efficiency of the subsequent hydrogenation for the selective synthesis of NH3. 91.7% NO3 - conversion rate is achieved for the reduction of 100mL 200mg L-1 NO3 --N, 99.3% ammonia (NH3 selectivity (yield of 1.79 mg h-1 cm-2), and 91.4% Faraday efficiency in 3 h. The high-purity solid NH4Cl is finally extracted by gas extraction and vacuum distillation (81.4% recovery). This study provides new insights and strategies for the conversion of NO3 - to NH3 products over iron-based electrocatalysts.

Electron-deficient CoO induced charge redistribution on CuCoO-NC nanohybrid for electrocatalytic reduction of nitrate to ammonia

The use of electrochemical tactics to reduce nitrate to the valorized product ammonia has become the hot topic. Recently, the synergistic effect of metal/metal oxide is provided to significantly enhance the electrocatalytic performance of nitrate reduction as opposed to monometallic catalyst. In this work, a reticulated fibre structure with Cu/CoO nanoparticles (CuxCoyO-NC) was prepared for electrocatalytic nitrate reduction (NO3-RR) to ammonia. The optimized catalyst (Cu1Co1O-NC) displayed brilliant performance for NO3-RR with high Faraday efficiency (FE) of 97.9 %, the excellent NH3 yield rate of 0.45 mmol h−1 cm−2, prominent NH3 selectivity of 98.4 % and efficient NO3– conversion of 99.2 % at −0.79 V vs reversible hydrogen electrode (RHE). Besides, Cu1Co1O-NC also exhibits the potential for uranium recovery from simulated wastewater containing nitrate and uranyl ions with a total yield of 508 mg ammonium diuranate after i-t measurement for 6 times. This work not only provides an efficient catalyst for reduction nitrate but also proposes the sustainable method for uranium containing sewage realizing nitrogen cycle.

Screening of Silver-Based Single-Atom Alloy Catalysts for NO Electroreduction to NH3 by DFT Calculations and Machine Learning.

Exploring NO reduction reaction (NORR) electrocatalysts with high activity and selectivity toward NH3 is essential for both NO removal and NH3 synthesis. Due to their superior electrocatalytic activities, single-atom alloy (SAA) catalysts have attracted considerable attention. However, the exploration of SAAs is hindered by a lack of fast yet reliable prediction of catalytic performance. To address this problem, we comprehensively screened a series of transition-metal atom doped Ag-based SAAs. This screening process involves regression machine learning (ML) algorithms and a compressed-sensing data-analytics approach parameterized with density-functional inputs. The results demonstrate that Cu/Ag and Zn/Ag can efficiently activate and hydrogenate NO with small Φmax(η), a grand-canonical adaptation of the Gmax(η) descriptor, and exhibit higher affinity to NO over H adatoms to suppress the competing hydrogen evolution reaction. The NH3 selectivity is mainly determined by the s orbitals of the doped single-atom near the Fermi level. The catalytic activity of SAAs is highly correlated with the local environment of the active site. We further quantified the relationship between the intrinsic features of these active sites and Φmax(η). Our work clarifies the mechanism of NORR to NH3 and offers a design principle to guide the screen of highly active SAA catalysts.

Regulating RuxMoy Nanoalloys Anchored on Porous Nitrogen-Doped Carbon via Domain-Confined Etching Strategy for Neutral Efficient Ammonia Electrosynthesis.

Neutral electrochemical nitrate (NO3-) reduction to ammonia involves sluggish and complex kinetics, so developing efficient electrocatalysts at low potential remains challenging. Here, we report a domain-confined etching strategy to construct RuxMoy nanoalloys on porous nitrogen-doped carbon by optimizing the Ru-to-Mo ratio, achieving efficient neutral NH3 electrosynthesis. Combining in situ spectroscopy and theoretical simulations demonstrated a rational synergic effect between Ru and Mo in nanoalloys that reinforces *H adsorption and lowers the energy barrier of NO3- hydrodeoxygenation for NH3 production. The resultant Ru5Mo5-NC surpasses 92.8% for NH3 selectivity at the potential range from -0.25 to -0.45 V vs RHE under neutral electrolyte, particularly achieving a high NH3 selectivity of 98.3% and a corresponding yield rate of 1.3 mg h-1 mgcat-1 at -0.4 V vs RHE. This work provides a synergic strategy that sheds light on a new avenue for developing efficient multicomponent heterogeneous catalysts.

Insight into the efficient electrochemical reduction of nitrate employing Pd/Ru bimetallic doped copper foam cathode: Selectivity and reliability

Nitrate pollution threatens ecological environment and human health. Electrochemical reduction of nitrate to ammonia using metal-doped modified cathode is a promising technique for nitrate removal. In this work, a bimetallic Ru/Pd-doped Cu foam (CF) electrode was developed for nitrate reduction using cation exchange method. Confirmed by various physio-chemical characterization, it was found that the Ru/Pd-Cu Spongy Copper Foam (SCF) was successfully prepared. In addition, nearly 100 % nitrate removal, 94.07 % NH3 selectivity, and 84.9 % Faradaic efficiency (FE) could be achieved, under the optimized conditions as 100 mg L−1 of initial NO3--N concentration, 0.3 mol L−1 of Na2SO4 as electrolyte and the applied current of 5.42 mA cm−2. Through electrochemical testing and DFT calculation, it was revealed that the bimetallic doping of Ru/Pd facilitate electrocatalytic nitrate reduction reaction (NO3RR) by reducing the energy barriers of the NO3--to-NH3 pathway from 0.81 to 0.56 eV. Besides, the electrode showed excellent stability and anti-toxicity even after 10 repeated NO3RR cycles, since the NH3 yield rate and NH3 selectivity ranged from 0.206 to 0.231 mg h−1 cm−2, 87–96.87 % respectively. After NO3RR, an extended electrochemical oxidation process was implemented to remove ammonia, and nearly 100 % of NH3 was oxidized to N2 without byproducts. Thereby, this study provides a new option for the electrochemical reduction of nitrate to ammonia via cathode modification, to achieve the substantial nitrate removal from nitrate-containing water.

Synergistic effect of rGO decoration on ZnFe2O4 nanorods for low concentration detection of ammonia at room temperature with high selectivity and response

This study introduces an improved sensor for detecting ammonia (NH₃) gas using Zinc Ferrite (ZF) decorated with reduced graphene oxide (rGO) films, prepared through spray pyrolysis and spin coating methods. NH₃, a major pollutant in fertilizer production, poses significant health and environmental risks even at low concentrations. Therefore, detecting NH₃ below exposure limits (25 ppm) is crucial for protecting ecosystems and human health. The prepared optimal rGO concentration and ZF (ZFG1.5) sensor exhibit excellent NH₃ response (45) towards 1 ppm, which is sevenfold better than the ZF film without rGO decoration. This enhancement is attributed to the ZF nanorods on the surface of the rGO, establishing a firm surface interaction with the ZF. This configuration accelerates electron transfer and promotes the adsorption/desorption of gas molecules, further contributing to the improved gas-solid interaction. Besides, the sensor demonstrated excellent repeatability (1.15 %), long-term stability, and high humidity tolerance (coefficient of variation 1.48 %). Additionally, the ZFG1.5 sensor showed a distinct selectivity for NH₃ in a mixed gas environment. The ZFG1.5 sensor is promising for real-time NH₃ monitoring below exposure limits, making it a valuable tool for environmental and health safety.

Selective electrosynthesis of ammonia via nitric oxide electroreduction catalyzed by copper nanowires infused in nitrogen-doped carbon nanorods

The electrochemical nitric oxide reduction reaction (eNORR) is meticulously investigated as an alternative to the energy intensive Haber-Bosch process to produce Ammonia (NH3). However, the eNORR is hindered by NH3 selectivity due to side reactions and mass-transfer limitations. In this work, we rationally designed copper nanowires (Cu NWs) infused in the lotus-root-like multi-nano-channels of the porous N-doped carbon nanorods (Cu-mNCNR) for a high selective eNORR to synthesize NH3 at ambient conditions. The optimized catalyst, Cu-mNCNR2, has achieved the highest NH3 Faradaic efficiency of 79% with NH3 yield rate of 34.5 μmol cm–2 h–1 at −0.4 VRHE. Moreover, the Cu-mNCNR2 has demonstrated a vigorous performance in the 24 h continuous NO electrolysis to produce NH3. Additionally, a prototype device, the Zn-NO battery, was demonstrated. This study shows that the rational design of a catalyst considering mass-transfer limitations is crucial to achieving high selective NH3 electrosynthesis in eNORR.

Reduced spinel oxide ZnCo2O4 with tetrahedral Co2+ sites for electrochemical nitrate reduction to ammonia and energy conversion

Electrocatalytic NO3− reduction to ammonia (NRA) at ambient conditions emerges as an appealing solution for green ammonia synthesis. In this work, we prepared a reduced Co-based spinel oxide for efficient ammonia synthesis and energy conversion. The in-depth structural characterization and electrochemical evaluation revealed thatthe introduction of Zn and reduction treatment led to the formation of electron-deficient tetrahedrally coordinated Co2+ sites. The resulting R-ZnCo2O4 exhibited remarkable NH3 production capacity with high NH3 selectivity of 92.2 %, FE of 92.3 %, and yield rate of 5.35 mgNH3 h−1 cm−2 (ca. 26.75 mgNH3 h−1 mgcat−1) under a low potential of − 0.3 V vs. RHE. The NRA pathway on R-ZnCo2O4 was further elucidated through DFT calculations and in situ characterizations. The high NRA efficiency of R-ZnCo2O4 was further explored in a Zn − NO3− battery, which was specified by an open circuit voltage of 1.46 V and a peak-power density of 1.40 mW cm−2, demonstrating its promising application for sustainable energy supply and green ammonia synthesis.

Electroreduction of nitrate to ammonia on graphyne-based single-atom catalysts by combined density functional theory and machine learning study

Nitrate pollution has emerged as a significant global issue, prompting increased interests in electrocatalytic reduction of nitrate to ammonia (NO3RR). This study explores the use of graphyne as the substrate to anchor single transition metal (TM) atoms from the 3d and 4d series on acetylene corners, creating single-atom catalysts (SAC) for the NO3RR reaction. Two catalysts, CrGY and MoGY, were finally identified as promising catalysts for NO3RR with low limiting potential and high selectivity for NH3. To further investigate the origin of catalyst activity, in addition to traditional electronic structrue analysis, machine learning models of the least solution shrinkage and selection operator (LASSO), the sure independence screening and sparsifying operator (SISSO) and the gradient boosting regression (GBR) algorithm are adopt to reveal the intrinsic properties of catalysts that determine the NO3RR performance. After preliminary evaluation of the 13 prepared features with LASSO algorithm, GBR models revealed that the nitrate adsorption free energy ΔGNO3- and the NO bond length are the two most important descriptors for NO3RR performance. A general equation for the relationship between the limiting potential and the characteristics of the catalysts are obtained by SISSO model. Finally, with the assitance of combined density functional calculations and machine learning, this study provides new enlightening insights into practical application of graphyne as SACs for NO3RR.

NiO-Incorporated Cu/Cu2O Nanowires for Highly Efficient Electrochemical Nitrate Reduction to Ammonia.

Electrochemical nitrate reduction to ammonia (NRA) is a promising sustainable way to synthesize ammonia (NH3) from nitrate (NO3-) contaminants. Cu-based electrocatalysts are frequently utilized for NRA due to their strong NO3- adsorption and de-oxygenation ability. However, this kind of catalyst usually possesses the weak water dissociation ability, resulting in insufficient proton supply in alkaline media to retard the following hydrogenation step of O-containing intermediates (*NOx, typically NO2-) to target NH3. Herein, NiO-incorporated Cu/Cu2O nanowires grown on nickel foam (p-CuNi@NF, p refers to plasma treatment) were synthesized via hydrothermal growth and subsequent O2 plasma treatment for efficient NRA electrocatalysis. On this p-CuNi@NF catalyst, NiO is able to accelerate the hydrogenation step by promoting the water dissociation to provide protons, ultimately facilitating efficient NRA. p-CuNi@NF exhibits excellent NH3 selectivity and yield in a wide potential range and reaches a high Faradaic efficiency (FENH3) of 97.5% and a yield (YNH3) of 470 μmol h-1 cm-2 at -0.6 V, both of which largely surpass the Cu/Cu2O catalyst.

Regioselective Doping into Atomically Aligned Core–Shell Structures for Electrocatalytic Reduction of Nitrate to Ammonia

AbstractThe electrochemical nitrate reduction reaction (NO3−RR) presents an environmentally friendly approach for efficient NO3− pollutant removal and ammonia (NH3) production, compared to the conventional Haber–Bosch approach. While core/shell engineering has demonstrated its potential in enhancing NO3−RR performance, significant synthetic challenges and limited shell layer modification capabilities impede the exploration of high‐performance NO3−RR core/shell catalysts. Herein, CuCoO/Co(OH)2 core/shell structure via in situ electrochemical activation is synthesized. The catalyst delivers a maximum NH3 Faradaic efficiency (FE) of 94.7% at −0.5 VRHE with excellent durability and selectivity for NH3 over a wide range of potentials in NO3−RR, surpassing the electrocatalytic performance of both undoped shell and core components. The outstanding performance Cu─CoO/Co(OH)2 is ascribed to the enhanced charge transfer, stabilization of key reaction intermediates, and regulation of hydrogen adsorption over Cu‐doped core/shell structure. Furthermore, the assembled Zn−NO3− battery device attains a peak current density exceeding 32 mA cm−2 and an NH3 yield of up to 145.4 µmol h−1 cm−2. The work offers a novel core/shell engineering strategy in electrocatalytic NO3−RR and sheds light on the doping effects on the electrochemical NH3 synthesis.

Selective and Efficient Electrocatalytic Synthesis of Ammonia from Nitrate with Copper‐Based Catalysts

AbstractThe high stability and persistence of nitrates in water poses a serious threat to human health and ecosystems. To effectively reduce the nitrate content in wastewater, the electrochemical nitrate reduction reaction (e‐NO3RR) is widely recognized as an ideal treatment method due to its high reliability and efficiency. The selection of catalyst material plays a decisive role in e‐NO3RR performance. Copper‐based catalysts, with their ease of acquisition, high activity, and selectivity for NH3, have emerged as the most promising candidates for e‐NO3RR applications. In this paper, the mechanism of e‐NO3RR is first introduced. Then the relationship between structural properties and catalytic performance of copper‐based catalysts is analyzed in detail from four aspects: nanomaterials, oxides, monoatomic, and bimetallic materials. Strategies for constructing efficient catalysts are discussed, including surface modulation, defect engineering, heteroatom doping, and coordination effects. Finally, the challenges and prospects of copper‐based catalysts with high e‐NO3RR performance in practical applications are outlined.

Phase-Engineered MoSe2/CeO2 Composites for Room-Temperature Gas Sensing with a Drastic Discrimination of NH3 and TEA Gases.

Detecting and distinguishing between hazardous gases with similar odors by using conventional sensor technology for safeguarding human health and ensuring food safety are significant challenges. Bulky, costly, and power-hungry devices, such as that used for gas chromatography-mass spectrometry (GC-MS), are widely employed for gas sensing. Using a single chemiresistive semiconductor or electric nose (e-nose) gas sensor to achieve this objective is difficult, mainly because of its selectivity issue. Thus, there is a need to develop new materials with tunable and versatile sensing characteristics. Phase engineering of two-dimensional materials to better utilize their physiochemical properties has attracted considerable attention. Here, we show that MoSe2 phase-transition/CeO2 composites can be effectively used to distinguish ammonia (NH3) and triethylamine (TEA) at room temperature. The phase transition of nanocomposite samples from semimetallic (1T) to semiconducting (2H) prepared at different synthesis temperatures is confirmed via X-ray photoelectron spectroscopy (XPS). A composite sensor in which the 2H phase of MoSe2 is predominant lacks discrimination capability and is less responsive to NH3 and TEA. An MoSe2/CeO2 composite sensor with a higher 1T phase content exhibits high selectivity for NH3, whereas one with a higher 2H phase content (2H > 1T) shows more selective behavior toward TEA. For example, for 50% relative humidity, the MoSe2/CeO2 sensor's signal changes from the baseline by 45% and 58% for 1 ppm of NH3 and TEA, respectively, indicating a low limit of detection (LOD) of 70 and 160 ppb, respectively. The composites' superior sensing characteristics are mainly attributed to their large specific surface area, their numerous active sites, presence of defects, and the n-n type heterojunction between MoSe2 and CeO2. The sensing mechanism is elucidated using Raman spectroscopy, XPS, and GC-MS results. Their phase-transition characteristics render MoSe2/CeO2 sensors promising for use in distributed, low-cost, and room-temperature sensor networks, and they offer new opportunities for the development of integrated advanced smart sensing technologies for environmental and healthcare.

Promoting active hydrogen supply for kinetically matched tandem electrocatalytic nitrate reduction to ammonia

Electrocatalytic nitrate reduction (NO3RR) shows admirable potential for environmental remediation and producing valuable NH3. However, the catalyst is restricted by the kinetic mismatch between NO3--to-NO2- and NO2--to-NH3, which results in excess NO2- and poor NH3 selectivity. Herein, a kinetically matched tandem electrocatalytic strategy with tunable active hydrogen(*H) supply is designed. The combination of Cu2O and Co11(HPO3)8(OH)6 (CoPO) playing key roles in NO3RR by i) on-demand supply of *H from CoPO; ii) the electronically coupled interface between Cu2O and CoPO enhance *H transfer kinetics. The Cu2O-CoPO-2 exhibits high NH3 yield of 22 mg cm−2 h−1 with Faradaic efficiency of 95 % at −0.37 V vs. RHE. In situ characterizations indicate the dynamic equilibrium between *H production and consumption contributes to high NO3RR performance. The techno-economic analyses reveal the system is economically viable compared to Haber-Bosch (H-B) process, which benefits from industrial current densities and superior energy efficiency at low potentials.

Superior selectivity for NH3 (NO2) gas molecules in In2SSe (Ga2SSe) Janus materials: a first-principles study

Anthropogenic gasses are very detrimental, requiring superior sensitive and selective materials to sense and segregate them. Using first-principles density functional theory (DFT) tools we have explored the sensitivity and selectivity of CO2, CO, NH3, NO2, H2S, and SO2 gases in the promising group-III Janus Ga2SSe and In2SSe nanostructured materials. We have explored all the possible adsorption sites in the Ga2SSe and In2SSe monolayer for sensing the gases and found that all the gasses are physisorbed in the sites with the lowest adsorption energy of −0.392 eV (−0.167 eV) for NH3 (NO2) on top of Indium (on the bridge-3 site) site of In2SSe (Ga2SSe). All adsorbed gasses significantly alter the bandgap of Ga2SSe and In2SSe from their pristine value and NO2-adsorbed M2SSe (M = Ga, In) structure exhibits significant bandgap changes: ∼0.16 eV reduction in Ga2SSe and ∼0.3 eV reduction in In2SSe from the pristine value, signifying substantial increase in conductivity. Additionally, analyzing the total density of states (TDOS), it can be concluded that NH3 at the Indium site of In2SSe and NO2 at the Bridge-3 site of Ga2SSe exhibit the most significant conductivity changes. Considering charge transfer, it is determined that 0.727 e/Å−3 of charge is transferred from In2SSe to NH3, while 1.05 e/Å−3 of charge is transferred from Ga2SSe to NO2 gas molecules, inferring that both NH3 and NO2 act as electron acceptors. Through this analysis, we found that NH3 is very selective on In2SSe while NO2 is selective on Ga2SSe Janus materials among the control gasses. This selectivity toward NH3 (NO2) gas on In2SSe (Ga2SSe) Janus material can open the new possibility of these materials for noxious gas sensing as well as NO2 utilization applications.

Effect of Temperature on Faradaic Efficiency and SEI Formation in Lithium Mediated Nitrogen Reduction

Lithium-mediated nitrogen reduction (Li-N2R) can be distributed and powered by renewable energy, making it a sustainable ammonia production alternative to the Haber Bosch process. While Haber Bosch is responsible for 1.3% of CO2 emissions yearly and requires centralized facilities with high temperatures and pressures, Li-N2R works at near-ambient conditions and therefore allows for decentralized production.1 First, lithium (Li+) ions electroplate as lithium metal on the working electrode. Second, the deposited lithium reacts with N2 gas to form lithium nitride (Li3N). Lastly, Li3N reacts with a proton source to form ammonia (NH3) (Figure Right).During Li-N2R, the NH3 selectivity is controlled through the mass transport of N2, Li+, and protons to the working electrode electrode (WE). The transport of these species is limited by the solid electrolyte interface (SEI), a passivation layer formed on top of the WE.2 The thickness and ratio of organic and inorganic species in the SEI change at different cycling temperatures, thus affecting the rates of transport between charge and uncharged species traveling to and from the electrode. Here, we study the impacts of temperature on FE and SEI composition in 1M LiBF4 in both diglyme (DG) and tetrahydrofuran (THF) with a 1v% ethanol (EtOH) proton source (Figure Left). Using ion chromatography (IC), nuclear magnetic resonance (NMR), and inductively coupled plasma mass spectrometry (ICP-MS) on the SEI dissolved in D2O, we quantify the SEI species formed at different cycling temperatures. Our correlation of temperature and SEI compositions to FE provide opportunities to engineer the SEI for improved Li-N2R FE and stability. 1J. W. Erisman et al., Nat. Geosci 2008. 1, 636–639 2K. Steinberg et al., Nat. Energy 2022, 8 (2), 138 Figure 1