MOLECULES
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2023
·Vol. 28
·期 24
·8013
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IF 4.6
Yuzhou Xia,Xinghe Xia,Shuying Zhu,Ruowen Liang,Guiyang Yan,Feng Chen,Xuxu Wang
Visible-light-driven N2reduction into NH3in pure H2O provides an energy-saving alternative to the Haber–Bosch process for ammonia synthesizing. However, the thermodynamic stability of N≡N and low water solubility of N2remain the key bottlenecks. Here, we propose a solution by developing a WO3−xhollow sphere with oxygen vacancies. Experimental analysis reveals that the hollow sphere structure greatly promotes the enrichment of N2molecules in the inner cavity and facilitates the chemisorption of N2onto WO3−x-HS. The outer layer’s thin shell facilitates the photogenerated charge transfer and the full exposure of O vacancies as active sites. O vacancies exposed on the surface accelerate the activation of N≡N triple bonds. As such, the optimized catalyst shows a NH3generation rate of 140.08 μmol g−1h−1, which is 7.94 times higher than the counterpart WO3-bulk.Keywords:WO3;hollow sphere;O defect;N2reduction;photocatalysis
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Jiangzhou Qin,Baojun Liu,Kwok-Ho Lam,Shijie Song,Xinyong Li,Xia Hu
To improve the photocatalytic efficiency of the N2 reduction reaction, MXene quantum dots (Ti3C2-QDs) and two-dimensional (2D) nickel metal–organic framework (Ni-MOF) with different ratios were fabricated by a simple self-assembly strategy to form type II heterojunctions. The resultant composites showed enhanced absorption and excellent interfacial charge-transfer capabilities according to the optical and photoelectron properties. The optimal Ti3C2-QD/Ni-MOF heterostructure exhibited a considerable ammonia yield rate (88.79 μmol gcat–1 h–1). By means of X-ray absorption near-edge fine structure (XANES) technique, it was found that the interaction of Ti3C2-QD and Ni-MOF could accelerate the electron transfer, and Ni site would be the main area to enrich the electron density as well as adsorb and activate N2. Finally, with the aid of density functional theory (DFT) calculations and in situ Fourier transform infrared spectrometry (FTIR), the reaction pathway and intermediate products were studied.
研究领域:
材料科学
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环境科学
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化学
✓ 已验证
产品关联
DOI
高影响因子
INORGANICA CHIMICA ACTA
·
2022
·
IF 3.118
Wei Wang,Jing-Zhe Li,Shi-Jian Luo,Zi-Xuan Yao,Kuan-Guan Liu
Using the atomic precisely structurally characterized clusters as electrocatalysts can provide some possible structure information about the active intermediate during the electrocatalytic N 2 reduction reaction (NRR) process. A Cu4 cluster, named [(bpy) 4 Cu 4 (C 10 H 8 SO 3 ) 4 (OH) 4 ]•4H 2 O ( 1 ), has been synthesized and fully characterized by IR, SXRD, XPS, EPR, et al. Single crystal structural analysis reveals that the core structure of the cluster has a step-scheme conformation with two μ 2 -OH and two μ 3 -OH groups. Electro-catalysis studies of this cluster show that it can achieve a highest NH 3 yield of 2.18 μg h −1 mg −1 and a FE of 0.97 % at −0.6 V. The excellent NRR performance may be attributable to the additional μ 3 -OH groups, based on the contrastively study of the other electrocatalysts of the Cu powder and the Cu 2 complex, named [(μ 2 -OH)(μ 2 -Cl)(bpy) 2 Cu 2 Cl 2 ] ( 2 ), with one μ 2 -OH group in its structure. This work provides some structure information about the possible active sites during the NRR process and inspires us to develop new cluster as efficient electrocatalysts for advancing sustainable NH 3 production. Using the atomic precisely structurally characterized clusters as electrocatalysts can provide some possible structure information about the active intermediate during the electrocatalytic N 2 reduction reaction (NRR) process. A Cu4 cluster, named [(bpy) 4 Cu 4 (C 10 H 8 SO 3 ) 4 (OH) 4 ]•4H 2 O ( 1 ), has been synthesized and fully characterized by IR, SXRD, XPS, EPR, et al. Single crystal structural analysis reveals that the core structure of the cluster has a step-scheme conformation with two μ 2 -OH and two μ 3 -OH groups. Electro-catalysis studies of this cluster show that it can achieve a highest NH 3 yield of 2.18 μg h −1 mg −1 and a FE of 0.97 % at −0.6 V. The excellent NRR performance may be attributable to the additional μ 3 -OH groups, based on the contrastively study of the other electrocatalysts of the Cu powder and the Cu 2 complex, named [(μ 2 -OH)(μ 2 -Cl)(bpy) 2 Cu 2 Cl 2 ] ( 2 ), with one μ 2 -OH group in its structure. This work provides some structure information about the possible active sites during the NRR process and inspires us to develop new cluster as efficient electrocatalysts for advancing sustainable NH 3 production.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
Sustainable Energy & Fuels
·
2019
·Vol. 4
·期 1
·164-170
·
IF 4.912
Shijian Luo,Xiaoman Li,Wanguo Gao,Haiqiang Zhang,Min Luo
Today, industrial ammonia synthesis mainly depends on the Haber–Bosch process, which causes a lot of energy consumption and huge CO2 emissions. The electrochemical N2 reduction reaction (NRR) is considered a more sustainable and environmentally benign alternative to produce ammonia, but it requires an efficient catalyst to overcome the difficulty of N2 activation. In this work, we reported that MOF-derived C@NiO@Ni microtubes behaved as a high-efficiency electrocatalyst in 0.1 M KOH electrolyte. This electrocatalyst achieved a high NH3 yield of 43.15 μg h−1 mgcat.−1 and faradaic efficiency of 10.9% at −0.7 V vs. a reversible hydrogen electrode. The experimental results indicated that the excellent NRR performance originated from the oxygen vacancies in NiO. Moreover, the abundant NiO/Ni interfaces were conducive to proton adsorption and further enhanced the NRR performance.
研究领域:
材料科学
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电化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
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IF 8.3
Lingjia Ma,Jiongliang Yuan,Zhaotao Liu,Yiqing Luo,Yuning Su,Kunye Zhu,Zefeng Feng,Huihua Niu,Shuaishuai Xiao,Jianjun Wei,Xu Xiang
The electrocatalytic synthesis of high-value-added urea by activating N2 and CO2 is a green synthesis technology that has achieved carbon neutrality. However, the chemical adsorption and C–N coupling ability of N2 and CO2 on the surface of the catalyst are generally poor, greatly limiting the improvement of electrocatalytic activity and selectivity in electrocatalytic urea synthesis. Herein, novel hierarchical mesoporous CeO2/Co3O4 heterostructures are fabricated, and at an ultralow applied voltage of −0.2 V, the urea yield rate reaches 5.81 mmol g–1 h–1, with a corresponding Faraday efficiency of 30.05%. The hierarchical mesoporous material effectively reduces the mass transfer resistance of reactants and intermediates, making it easier for them to access active centers. The emerging space-charge regions at the heterointerface generate local electrophilic and nucleophilic regions, facilitating CO2 targeted adsorption in the electrophilic region and activation to produce *CO intermediates and N2 targeted adsorption in the nucleophilic region and activation to generate *N ═ N* intermediates. Then, the electrons in the σ orbitals of *N ═ N* intermediates can be easily accepted by the empty eg orbitals of Co3+ in CeO2/Co3O4, which presents a low-spin state (LS: t2g6eg0). Subsequently, *CO couples with *N ═ N* to produce the key intermediate *NCON*. Interestingly, it was discovered through in situ Raman spectroscopy that the CeO2/Co3O4 catalyst has a reversible spinel structure before and after the electrocatalytic reaction, which is due to the surface reconstruction of the catalyst during the electrocatalytic reaction process, producing amorphous active cobalt oxides, which is beneficial for improving electrocatalytic activity.
研究领域:
材料科学
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电化学
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催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Energy Materials
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2019
·
IF 0
Ke Chu,Ya-ping Liu,Jing Wang,Hu Zhang
Current artificial NH3 synthesis relies heavily on the Haber–Bosch process that involves enormous energy consumption and huge CO2 emission. The electrochemical N2 reduction reaction (NRR) offers an eco-friendly and sustainable alternative but demands cost-effective and efficient NRR electrocatalysts. Herein, NiO nanodots (∼2 nm) supported on graphene (NiO/G) were developed as a high-performance NRR electrocatalyst at ambient conditions. Electrochemical tests indicated that the NiO/G exhibited a high NH3 yield (18.6 μg h–1 mg–1) and Faradaic efficiency (7.8%) at −0.7 V vs reversible hydrogen electrode, outperforming the most reported NRR electrocatalysts. Experimental and density functional theory (DFT) results revealed that NiO was the dominating active center, and nanodot structure enabled the NiO to expose more active sites. DFT results further demonstrated that the distal associative route was the preferable NRR pathway with *N2 → *NNH being the rate-determining step.
研究领域:
材料科学
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电催化
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能源与环境科学
✓ 已验证
产品关联
DOI
Sustainable Materials and Technologies
·
2024
·
IF 8.6
Lei Guo,Yan-He Chen,Li-Mei Xu,Xiao-Lu Chen,Jin-Qiu Shen,Jian-Yong Zhang,Zhen-Jiang Liu
Herein, a fern-like p-n heterojunction by anchoring Ni 3 Fe-LDH nanoplates onto Co 3 O 4 nanoneedles have been optionally constructed. Essentially, p-n heterojunction ensured to induce strong built-in electric field, and inherit interfacial electron redistribution. Based on their compatible and well-matched electronic band structures, a staggered type-II photo-generated electron/holes transfer pathway have been elaborated by density functional theory calculation (DFT), in situ irradiation X-ray photoelectron spectroscopy (XPS), and fluorescent decay. This band bending and charge migrating module conferred the architecture with strong redox ability, sufficient exciton dissociation, and admirable optoelectronic characteristics. Moreover, the heterostructure acquired broad absorption spectrum to exhibit outperforming photocatalytic effect. Totally, this electron redistribution at the hierarchical interface, a type-II scheme charge-transfer pathway and the oxygen defects would lead to high efficiency in solar light assisted N 2 reduction. Typically, Co@Ni 3 Fe-2 catalyst exhibited the highest NH 3 production rate of 16.15 μg h −1 mg cat. −1 and Faraday efficiency (FE) of 31.57% at −0.6 V vs. RHE in 0.1 M Na 2 SO 4 solution. Fortunately, with light exposure, the NH 3 production rate and FE could increase by 27.9% and 18.1% than that under dark. This work would provide a plausible attitude towards the design of high efficient photocatalyst for artificial photosynthesis with multi-functionalized coupling effect.
研究领域:
材料科学
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催化
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光化学
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理论化学
✓ 已验证
产品关联
DOI
高影响因子
Nano Energy
·
2019
·
IF 15.548
Mingli Zhang,Changhyeok Choi,Rupeng Huo,Geun Ho Gu,Song Hong,Chao Yan,Suying Xu,Alex W. Robertson,Jieshan Qiu,Yousung Jung,Zhenyu Sun
Electrochemical nitrogen fixation under mild conditions is highly demanded yet remains a grand challenge. Herein we report metal-free electrocatalysis of aqueous N 2 reduction to produce NH 3 over reduced graphene oxide (DrGO) with tuned defects. The defect sites in DrGO, consisting of unsaturated carbon [single vacancy (SV), double vacancy (DV), and –COOH], were examined, and showed an improved NH 3 selectivity due to the strong binding of N 2 instead of H. In addition to improved selectivity, the calculated free energies for N 2 reduction reaction at DrGO-COOH and DrGO-DV sites suggest that the thermodynamic overpotentials of these metal-free catalysts are comparable to the most efficient transition metal-based catalysts reported thus far. Our nonmetallic and dopant-free catalysts can convert N 2 to NH 3 at a faradaic efficiency of up to 22.0% at −0.116 V (versus the reversible hydrogen electrode vs . RHE) in 0.1 M HCl and 10.8% at −0.166 V ( vs . RHE) in 0.1 M KOH, surpassing most earlier reported catalysts. An NH 3 formation rate exceeding 7.3 μg h −1 mg −1 was achieved at low overpotentials in both acidic and alkaline environments , comparable to the values shown by metal electrocatalysts under similar conditions.
研究领域:
材料科学
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电化学
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催化
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2020
·
IF 16.683
Jinxiu Zhao,Xuejing Liu,Xiang Ren,Xu Sun,Dongxu Tian,Qin Wei,Dan Wu
Electrochemical N 2 reduction is developing as an appealing carbon-neutral strategy for NH 3 artificial synthesis but seriously influenced by requiring high-efficiency electrocatalysts for the N 2 activation at ambient conditions. Here, we reported that defective-rich ZnS nanoparticles supported on reduced graphene oxide (DR ZnS-rGO) acts as a high-efficiency electrocatalyst for ambient N 2 -to-NH 3 conversion with excellent selectivity. In 0.1 M HCl, such DR ZnS-rGO presents a large NH 3 yield of 51.2 μg h –1 mg cat. –1 (−0.15 V vs . reversible hydrogen electrode, RHE) and a high faradic efficiency of 28.2 % (−0.10 V vs . RHE), as well as high electrochemical and structure stability. Isotopic labelling samples experiments reveal that the synthetic NH 3 directly arise from the supplied N 2 . Density functional theory calculations demonstrated that the engineering S vacancies in DR ZnS-rGO not only provide reaction sites for N 2 -to-NH 3 conversion but activate of N 2 molecules.
研究领域:
材料科学
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电化学
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催化
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）