302-01-2Relevant articles and documents
A tuned Lewis acidic catalyst guided by hard-soft acid-base theory to promote N2electroreduction
Ding, Yiwang,Hong, Jiafu,Qiu, Jieshan,Ren, Yongwen,Song, Xuedan,Tan, Xinyi,Wei, Qianbing,Yu, Chang,Zhou, Fengyi
supporting information, p. 13036 - 13043 (2021/06/16)
The electrocatalytic N2reduction 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 the process, the design strategy of the electrocatalyst for enhancing the N2activation ability is still in a trial-and-error stage due to the absence of theoretical guidance. As a result, the corresponding NH3yield rate and selectivity are much lower than that required for implementation at scale. In this work, on the basis of the hard-soft acid-base theory, we report a paradigm for the design of an electrocatalyst with tuned Lewis acidity to efficiently activate and reduce N2to NH3. As a proof of concept, it is revealed that enhancing the Lewis acidity of the molybdenum sulfide (MoSx) model catalyst supported on carbon nanotubes can greatly improve its activation ability toward the N2molecule. Accordingly, a high faradaic efficiency of 21.60 ± 2.35% and NH3yield rate of 40.4 ± 3.6 μg h?1mgcat.?1are obtained over the modified MoSx, which are ～2 times enhanced in comparison with the original MoSx, respectively. Density functional theory calculations verify that the electron transfer from the occupied σ orbitals of N2to the empty d orbitals of Mo sites within MoSxcan be greatly accelerated by tuning the Lewis acidity of MoSxto match with the basicity of N2, thereby enhancing the N2activation processviathe σ → d donation mechanism.
Rational design of bimetallic Rh0.6Ru0.4nanoalloys for enhanced nitrogen reduction electrocatalysis under mild conditions
Zhao, Lei,Liu, Xuejing,Zhang, Shen,Zhao, Jie,Xu, Xiaolong,Du, Yu,Sun, Xu,Zhang, Nuo,Zhang, Yong,Ren, Xiang,Wei, Qin
supporting information, p. 259 - 263 (2021/01/14)
As a carbon-free reaction process, the electrocatalytic nitrogen reduction reaction (eNRR) under mild conditions has broad prospects for green and sustainable NH3 production. In this work, bimetallic RhRu nanoalloys (NAs) with cross-linked curly nanosheets were successfully prepared and exhibited exciting results in the eNRR process. Furthermore, the composition effect of RhRu NAs on eNRR activity was studied systematically, and the results showed that Rh0.6Ru0.4 NAs/CP exhibited the highest NH3 yield rate of 57.75 μg h-1 mgcat.-1 and faradaic efficiency of 3.39%. As an eNRR catalyst with great potential, Rh0.6Ru0.4 NAs extend the possibility of alloy-nanomaterials in the eNRR field and further provide an idea for the precise structure of more effective and stable electrocatalysts.
A shape-memory V3O7·H2O electrocatalyst for foldable N2fixation
Sun, Yuntong,Ding, Shan,Zhang, Chen,Duan, Jingjing,Chen, Sheng
, p. 1603 - 1609 (2021/02/03)
Shape-memory materials can retain their functionalities during mechanical deformation, and thus hold great promise for utilizations in versatile, wearable and portable systems. Here, we report a shape-memory V3O7·H2O monolith that works as a new emerging foldable electrocatalyst for nitrogen reduction reaction (NRR). Remarkably, the electrocatalyst has been designed according to our unexpected observation that metal oxides, commonly considered as a class of tough and brittle materials, can show shape-memory properties after anisotropic alignment of their microstructures via an ice-Templated freeze-casting method. We demonstrate the V3O7·H2O electrocatalyst for promoting the NRR characteristic of excellent performances, including an ammonia yield rate of 36.42 μg h-1 mg-1, faradaic efficiency of 14.20% at-0.55 V (vs. RHE), and operation for seven cycles without activity or structural degradation. Remarkably, NRR faradaic efficiencies do not change during electrode deformations, while ammonia yield rates only show a slight decline even after significant foldings. We further elucidate through density function theory that NRR proceeds at vanadium active sites of V3O7·H2O via the associative distal pathway with ?N2 + H+ → ?N2H as the rate-limiting step. This journal is
Enhancing electrocatalytic nitrogen reduction to ammonia with rare earths (La, Y, and Sc) on high-index faceted platinum alloy concave nanocubes
Chen, You-Hu,Jiang, Xin,Liao, Hong-Gang,Liu, Feng,Mao, Yu-Jie,Sheng, Tian,Sun, Shi-Gang,Wei, Lu,Ye, Jin-Yu,Zhao, Xin-Sheng
, p. 26277 - 26285 (2021/12/10)
Surface structure effect is the key subject in electrocatalysis, and consists of the structure dependence of interaction between reaction molecules and the catalyst surface in specifying the surface atomic arrangement, chemical composition and electronic structure. Herein, we develop a controllable synthesis of Pt-RE (RE = La, Y, Sc) alloy concave nanocubes (PtRENCs) with {410} high-index facets (HIFs) by an electrochemical method in a choline chloride-urea based deep eutectic solvent. The PtRENCs are used as an efficient catalyst in electrocatalytic nitrogen reduction to ammonia (NH3). Owing to the high density of low-coordinated Pt step sites (HIF structure) and the unique electronic effect of Pt-RE, the as-prepared PtRENCs exhibit an excellent electrocatalytic performance for the nitrogen reduction reaction (NRR) under ambient conditions. The NH3 yield rate and faradaic efficiency (FE) share the same trend of Pt-La (rNH3: 71.4 μg h-1 μgcat-1, FE: 35.6%) > Pt-Y (rNH3: 65.2 μg h-1 μgcat-1, FE: 26.7%) > Pt-Sc (rNH3: 48.5 μg h-1 μgcat-1, FE: 19%) > Pt (rNH3: 25.8 μg h-1 μgcat-1, FE: 10.7%). Moreover, the PtRENCs demonstrate high selectivity for N2 reduction to NH3 and high stability retaining 90% of the NH3 yield rate and FE values after 12 h continuous NRR tests. Density functional theory (DFT) calculations indicate that the rate determining step of the NRR process is the formation of N2H2? from N2 with the transfer of two proton-coupled electrons, and the upshift of the d-band center boosts the NRR activity by enhancing the bonding strength of reaction intermediates on the high-index faceted Pt-RE (RE = La, Y, Sc) alloying surface. In addition, the introduction of RE (RE = La, Y, Sc) on the Pt step surface can effectively suppress the HER process and provide appropriate sites for the NRR. This journal is
In-situ formation of bismuth nanoparticles on nickel foam for ambient ammonia synthesis via electrocatalytic nitrogen reduction
Li, Guangzhe,Pan, Zhefei,Lin, He,An, Liang
, (2021/05/04)
Bismuth has been regarded as a promising electrocatalyst for triggering nitrogen reduction to ammonia, due to the ease of nitrogen dissociation rendered by the strong interaction between Bi 6p band and the N 2p orbitals. However, the poor conductivity of bismuth limits the electron transfer for nitrogen reduction. In addition, the sluggish water dissociation on the bismuth surface leads to insufficient proton supply for the protonation step of *N2, causing inferior ammonia production performance. In this work, we prepare an integrated and binder-free bismuth nanoparticles@nickel foam electrode for ambient ammonia synthesis via a facile displacement reaction. Using nickel foam as the conductive substrate improves the electron transfer of bismuth for nitrogen reduction to ammonia. In addition, enhanced water dissociation on the nickel surface improves the protonation of *N2 by supplying adequate protons via hydrogen spillover, thus boosting the ammonia production performance. This integrated electrode eliminates the use of polymer binders and reduces the contact resistance between the diffusion layer and catalyst layer, facilitating electron delivery and reducing cell resistance, thus requiring less energy input for ammonia production. The performance examination in an electrochemical H-type cell shows that an ammonia yield rate as high as of 9.3 × 10?11 mol s?1 cm?2 and a Faradaic efficiency of 6.3% are achieved. An ammonia yield rate of 8.19 × 10?11 mol s?1 cm?2 is observed after 6 cycles, with a retention rate of 88%.
Rigid two-dimensional indium metal-organic frameworks boosting nitrogen electroreduction at all pH values
Chen, Sheng,Ding, Shan,Duan, Jingjing,Sun, Yuntong,Xia, Baokai,Yu, Licheng
supporting information, p. 20040 - 20047 (2021/09/20)
Based on an ion exchange and dissolution-recrystallization mechanism, rigid indium metal-organic framework (In-MOF) nanosheets have been synthesized under mild conditions. The collective advantages of the rigid structure and two-dimensional architecture (thickness: 1.3 nm) enable In-MOF to show great activity during nitrogen electroreduction and excellent stability over a wide pH range. At pH values ?1mg?1(or 4.94 μg h?1cm?2) and faradic efficiency ≥6.72%. At pH values ≥7, 2D In-MOF can operate efficiently with a record NH3yield of 79.20 μg h?1mg?1(or 15.94 μg h?1cm?2) and faradic efficiency of 14.98%, making it one of the most active MOF-based electrocatalysts for nitrogen electroreduction. Furthermore, the reaction mechanism of nitrogen electroreduction has been revealed using density function theory (DFT) simulations, and it follows enzymatic pathways at all pH values, with the potential determining step being *H2NNH2* → *NH2+ NH3. It is expected that the present study will offer valuable clues for the design and fabrication of low-cost and efficient all-pH nitrogen reduction electrocatalysts for industrial applications.
High-performance ammonia fixation electrocatalyzed by ReS2nanosheet array
Zhang, Lunwen,Xue, Xiaodong,Gao, Min,Zhao, Jinxiu,Yan, Tao,Yu, Cuiping,Zhao, Lei,Ren, Xiang,Wei, Qin
supporting information, p. 11457 - 11460 (2021/07/13)
The industrial-scale NH3 production still heavily depends on the Haber-Bosch process, which not only demands high energy consumption but also emits a large amount of CO2. The electrochemical fixation of N2 to NH3 under ambient conditions is regarded as an eco-friendly and sustainable approach, but stable and efficient electrocatalysts are demanded for the N2 reduction reaction under ambient conditions. In this communication, ReS2 nanosheet array on carbon cloth (ReS2/CC) is first utilized in NRR. This ReS2/CC exhibits high catalytic activity and strong long-term electrochemical durability. The Faraday efficiency of ReS2/CC is 0.78% and the NH3 yield of ReS2/CC is 3.61 × 10-10 mol s-1 cm-2 at -0.4 V versus reversible hydrogen electrode in 0.1 M HCl.
Enhanced N2affinity of 1T-MoS2with a unique pseudo-six-membered ring consisting of N-Li-S-Mo-S-Mo for high ambient ammonia electrosynthesis performance
Patil, Shivaraj B.,Chou, Hung-Lung,Chen, Yu-Mei,Hsieh, Shang-Hsien,Chen, Chia-Hao,Chang, Chia-Che,Li, Shin-Ren,Lee, Yi-Cheng,Lin, Ying-Sheng,Li, Hsin,Chang, Yuan Jay,Lai, Ying-Huang,Wang, Di-Yan
supporting information, p. 1230 - 1239 (2021/01/25)
The Haber-Bosch process is widely used to convert atmospheric nitrogen (N2) into ammonia (NH3). However, the extreme reaction conditions and abundant carbon released by this process make it important to develop a greener NH3 production method. The electrochemical nitrogen reduction reaction (NRR) is an attractive alternative to the Haber-Bosch process. Herein, we demonstrated that molybdenum sulfide on nickel foil (1T-MoS2-Ni) with low crystallinity was an active NRR electrocatalyst. 1T-MoS2-Ni achieved a high faradaic efficiency of 27.66% for the NRR at -0.3 V (vs. RHE) in a LiClO4 electrolyte. In situ X-ray diffraction and ex situ X-ray photoemission analyses showed that lithium ions were intercalated into the 1T-MoS2 layers during the NRR. Moreover, theoretical calculations revealed the differences between six membered rings formed in the 1T-MoS2 and 2H-MoS2 systems with Li intercalation. The bond distances of d(Mo-N) and d(N-Li) of in Li-1T-MoS2 were found to be shorter than those in Li-2H-MoS2, resulting in a lower energy barrier of N2 fixation and higher NRR activity. Therefore, 1T-MoS2-Ni is promising as a scalable and low-cost NRR electrocatalyst with lower power consumption and carbon emission than the Haber-Bosch process.
Nitrogen reduction through confined electro-catalysis with carbon nanotube inserted metal-organic frameworks
Lv, Yang,Wang, Yiqi,Yang, Miao,Mu, Zhangyan,Liu, Shengtang,Ding, Weiping,Ding, Mengning
supporting information, p. 1480 - 1486 (2021/02/03)
Carbon-based nanomaterials are widely used in electro-catalysis because of their low cost, high conductivity and stability. However, their application towards selective electrochemical reduction of nitrogen to ammonia suffers from low activity and faradaic efficiency (FE). Here, we report a confined electrocatalysis strategy for enhanced ammonia production and FE in the electrochemical nitrogen reduction reaction (eNRR), by the construction of a carbon nanotube (CNT or NCNT) inserted porous metal-organic framework (MOF). The CNT/NCNT serves as the catalytic center and ensures an efficient pathway for electron conduction that is essential to electrocatalysis, while the general relative hydrophobicity within the MOF enriches the local concentration of N2 near the catalyst active sites, and more importantly suppresses the hydrogen evolution reaction (HER) to facilitate the FE. Among the systematically screened MOF and carbon nanotubes, NCNT@MIL-101(Fe) demonstrates the highest activity of 607.35 μg h-1 mgNCNT-1 and CNT@MIL-101(Fe) achieves the best FE of 37.28%. The significantly improved NRR performance of CNT@MOFs and NCNT@MOFs demonstrates the successful employment of confined catalysis in electrochemical reactions, which provides an alternative strategy for catalyst design in nitrogen fixation. This journal is
Redox-Mediated Ambient Electrolytic Nitrogen Reduction for Hydrazine and Ammonia Generation
Huang, Shiqiang,Huang, Songpeng,Li, Mengsha,Salla, Manohar,Wang, Qing,Wang, Xun,Xi, Shibo,Yang, Jing,Yang, Yi,Zhang, Feifei,Zhang, Yong-Wei,Zhu, Ming-Ke
supporting information, p. 18721 - 18727 (2021/07/20)
This work presents a redox-mediated electrolytic nitrogen reduction reaction (RM-eNRR) using polyoxometalate (POM) as the electron and proton carrier which frees the TiO2-based catalyst from the electrode and shifts the reduction of nitrogen to a reactor tank. The RM-eNRR process has achieved an ammonium production yield of 25.1 μg h?1 or 5.0 μg h?1 cm?2 at an ammonium concentration of 6.7 ppm. With high catalyst loading, 61.0 ppm ammonium was accumulated in the electrolyte upon continuous operation, which is the highest concentration detected for ambient eNRR so far. The mechanism underlying the RM-eNRR was scrutinized both experimentally and computationally to delineate the POM-mediated charge transfer and hydrogenation process of nitrogen molecule on the catalyst. RM-eNRR is expected to provide an implementable solution to overcome the limitations in the conventional eNRR process.
