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1.
Shenlong Zhao Xunyu Lu Lianzhou Wang Julian Gale Rose Amal 《Advanced materials (Deerfield Beach, Fla.)》2019,31(13)
The electrocatalytic nitrogen reduction reaction (NRR) is a promising catalytic system for N2 fixation in ambient conditions. Currently, metal‐based catalysts are the most widely studied catalysts for electrocatalytic NRR. Unfortunately, the low selectivity and poor resistance to acids and bases, and the low Faradaic efficiency, production rate, and stability of metal‐based catalysts for NRR make them uncompetitive for the synthesis of ammonia in comparison to the industrial Haber–Bosch process. Inspired by applications of carbon‐based metal‐free catalysts (CMFCs) for the oxygen reduction reaction (ORR) and CO2 reduction reaction (CO2RR), the studies of these CMFCs in electrocatalytic NRR have attracted great attention in the past year. However, due to the differences in electrocatalytic NRR, there are several critical issues that need to be addressed in order to achieve rational design of advanced carbon‐based metal‐free electrocatalysts to improve activity, selectivity, and stability for NRR. Herein, the recent developments in the field of carbon‐based metal‐free NRR catalysts are presented, along with critical issues, challenges, and perspectives concerning metal‐free catalysts for electrocatalytic reduction of nitrogen for synthesis of ammonia at ambient conditions. 相似文献
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Zhibo Cui Wensheng Jiao ZeYi Huang Guanzhen Chen Biao Zhang Yunhu Han Wei Huang 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(35):2301465
Hydrogen energy is regarded as the ultimate energy source for future human society, and the preparation of hydrogen from water electrolysis is recognized as the most ideal way. One of the key factors to achieve large-scale hydrogen production by water splitting is the availability of highly active and stable electrocatalysts. Although non-precious metal electrocatalysts have made great strides in recent years, the best hydrogen evolution reaction (HER) electrocatalysts are still based on noble metals. Therefore, it is particularly important to improve the overall activity of the electrocatalysts while reducing the noble metals load. Alloying strategies can shoulder the burden of optimizing electrocatalysts cost and improving electrocatalysts performance. With this in mind, recent work on the application of noble metal-based alloy electrocatalysts in the field of hydrogen production from water electrolysis is summarized. In this review, first, the mechanism of HER is described; then, the current development of synthesis methods for alloy electrocatalysts is presented; finally, an example analysis of practical application studies on alloy electrocatalysts in hydrogen production is presented. In addition, at the end of this review, the prospects, opportunities, and challenges facing noble metal-based alloy electrocatalysts are tried to discuss. 相似文献
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Wei Li Dongdong Wang Yiqiong Zhang Li Tao Tehua Wang Yuqin Zou Yanyong Wang Ru Chen Shuangyin Wang 《Advanced materials (Deerfield Beach, Fla.)》2020,32(19):1907879
The commercialization of fuel cells, such as proton exchange membrane fuel cells and direct methanol/formic acid fuel cells, is hampered by their poor stability, high cost, fuel crossover, and the sluggish kinetics of platinum (Pt) and Pt-based electrocatalysts for both the cathodic oxygen reduction reaction (ORR) and the anodic hydrogen oxidation reaction (HOR) or small molecule oxidation reaction (SMOR). Thus far, the exploitation of active and stable electrocatalysts has been the most promising strategy to improve the performance of fuel cells. Accordingly, increasing attention is being devoted to modulating the surface/interface electronic structure of electrocatalysts and optimizing the adsorption energy of intermediate species by defect engineering to enhance their catalytic performance. Defect engineering is introduced in terms of defect definition, classification, characterization, construction, and understanding. Subsequently, the latest advances in defective electrocatalysts for ORR and HOR/SMOR in fuel cells are scientifically and systematically summarized. Furthermore, the structure–activity relationships between defect engineering and electrocatalytic ability are further illustrated by coupling experimental results and theoretical calculations. With a deeper understanding of these complex relationships, the integration of defective electrocatalysts into single fuel-cell systems is also discussed. Finally, the potential challenges and prospects of defective electrocatalysts are further proposed, covering controllable preparation, in situ characterization, and commercial applications. 相似文献
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Tianyi Xiang Yuntao Liang Yuxi Zeng Jie Deng Jili Yuan Weiping Xiong Biao Song Chengyun Zhou Yang Yang 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(41):2303732
Excessive accumulation of nitrate in the environment will affect human health. To combat nitrate pollution, chemical, biological, and physical technologies have been developed recently. The researcher favors electrocatalytic reduction nitrate reaction (NO3RR) because of the low post-treatment cost and simple treatment conditions. Single-atom catalysts (SACs) offer great activity, exceptional selectivity, and enhanced stability in the field of NO3RR because of their high atomic usage and distinctive structural characteristics. Recently, efficient transition metal-based SACs (TM-SACs) have emerged as promising candidates for NO3RR. However, the real active sites of TM-SACs applied to NO3RR and the key factors controlling catalytic performance in the reaction process remain ambiguous. Further understanding of the catalytic mechanism of TM-SACs applied to NO3RR is of practical significance for exploring the design of stable and efficient SACs. In this review, from experimental and theoretical studies, the reaction mechanism, rate-determining steps, and essential variables affecting activity and selectivity are examined. The performance of SACs in terms of NO3RR, characterization, and synthesis is then discussed. In order to promote and comprehend NO3RR on TM-SACs, the design of TM-SACs is finally highlighted, together with the current problems, their remedies, and the way forward. 相似文献
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Yuhuan Cui Anqi Dong Yitong Zhou Yanbin Qu Ming Zhao Zhili Wang Qing Jiang 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(17):2207661
Electrochemical reduction of nitrate to ammonia (NH3) not only offers a promising strategy for green NH3 synthesis, but also addresses the environmental issues and balances the perturbed nitrogen cycle. However, current electrocatalytic nitrate reduction processes are still inefficient due to the lack of effective electrocatalysts. Here 3D nanoporous Cu/MnOx hybrids are reported as efficient and durable electrocatalysts for nitrate reduction reaction, achieving the NH3 yield rates of 5.53 and 29.3 mg h−1 mgcat.−1 with 98.2% and 86.2% Faradic efficiency in 0.1 m Na2SO4 solution with 10 and 100 mm KNO3, respectively, which are higher than those obtained for most of the reported catalysts under similar conditions. Both the experimental results and density functional theory calculations reveal that the interface effect between Cu/MnOx interface could reduce the free energy of rate determining step and suppress the hydrogen evolution reaction, leading to the enhanced catalytic activity and selectivity. This work provides an approach to design advanced materials for NH3 production via electrochemical nitrate reduction. 相似文献
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Huanyu Jin Laiquan Li Xin Liu Cheng Tang Wenjie Xu Shuangming Chen Li Song Yao Zheng Shi‐Zhang Qiao 《Advanced materials (Deerfield Beach, Fla.)》2019,31(32)
Electrochemical nitrogen reduction reaction (NRR) under ambient conditions provides an avenue to produce carbon‐free hydrogen carriers. However, the selectivity and activity of NRR are still hindered by the sluggish reaction kinetics. Nitrogen Vacancies on transition metal nitrides are considered as one of the most ideal active sites for NRR by virtue of their unique vacancy properties such as appropriate adsorption energy to dinitrogen molecule. However, their catalytic performance is usually limited by the unstable feature. Herein, a new 2D layered W2N3 nanosheet is prepared and the nitrogen vacancies are demonstrated to be active for electrochemical NRR with a steady ammonia production rate of 11.66 ± 0.98 µg h?1 mgcata?1 (3.80 ± 0.32 × 10?11 mol cm?2 s?1) and Faradaic efficiency of 11.67 ± 0.93% at ?0.2 V versus reversible hydrogen electrode for 12 cycles (24 h). A series of ex situ synchrotron‐based characterizations prove that the nitrogen vacancies on 2D W2N3 are stable by virtue of the high valence state of tungsten atoms and 2D confinement effect. Density function theory calculations suggest that nitrogen vacancies on W2N3 can provide an electron‐deficient environment which not only facilitates nitrogen adsorption, but also lowers the thermodynamic limiting potential of NRR. 相似文献
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Hongjing Wang Hongjie Yu Ziqiang Wang Yinghao Li You Xu Xiaonian Li Hairong Xue Liang Wang 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(6)
Electrochemical reduction of N2 to NH3 provides an alternative strategy to replace the industrial Haber–Bosch process for facile and sustainable production of NH3. The development of efficient electrocatalysts for the nitrogen reduction reaction (NRR) is highly desired. Herein, a micelle‐assisted electrodeposition method is presented for the direct fabrication of porous Au film on Ni foam (pAu/NF). Benefiting from its interconnected porous architectonics, the pAu/NF exhibits superior NRR performance with a high NH3 yield rate of 9.42 µg h?1 cm?2 and a superior Faradaic efficiency of 13.36% at ?0.2 V versus reversible hydrogen electrode under the neutral electrolyte (0.1 m Na2SO4). The proposed micelle‐assisted electrodeposition strategy is highly valuable for future design of active NRR catalysts with desired compositions toward various electrocatalysis fields. 相似文献
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Electrochemical Ammonia Synthesis via Nitrogen Reduction Reaction on a MoS2 Catalyst: Theoretical and Experimental Studies
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Ling Zhang Xuqiang Ji Xiang Ren Yongjun Ma Xifeng Shi Ziqi Tian Abdullah M. Asiri Liang Chen Bo Tang Xuping Sun 《Advanced materials (Deerfield Beach, Fla.)》2018,30(28)
The discovery of stable and noble‐metal‐free catalysts toward efficient electrochemical reduction of nitrogen (N2) to ammonia (NH3) is highly desired and significantly critical for the earth nitrogen cycle. Here, based on the theoretical predictions, MoS2 is first utilized to catalyze the N2 reduction reaction (NRR) under room temperature and atmospheric pressure. Electrochemical tests reveal that such catalyst achieves a high Faradaic efficiency (1.17%) and NH3 yield (8.08 × 10?11 mol s?1 cm?1) at ?0.5 V versus reversible hydrogen electrode in 0.1 m Na2SO4. Even in acidic conditions, where strong hydrogen evolution reaction occurs, MoS2 is still active for the NRR. This work represents an important addition to the growing family of transition‐metal‐based catalysts with advanced performance in NRR. 相似文献
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Yuanyuan Ma Tong Yang Haiyuan Zou Wenjie Zang Zongkui Kou Lu Mao Yuanping Feng Lei Shen Stephen J. Pennycook Lele Duan Xu Li John Wang 《Advanced materials (Deerfield Beach, Fla.)》2020,32(33):2002177
Previous research of molybdenum-based electrocatalysts for nitrogen reduction reaction (NRR) has been largely considered on either isolated Mo single atoms (MoSAs) or Mo carbide particles (e.g., Mo2C) separately, while an integrated synergy (MoSAs-Mo2C) of the two has never been considered. The theoretical calculations show that the Mo single atoms and Mo2C nanoparticles exhibit, respectively, different catalytic hydrogen evolution reaction and NRR selectivity. Therefore, a new role-playing synergistic mechanism can be well enabled for the multistep NRR, when the two are combined on the same N-doped carbon nanotubes (NCNTs). This hypothesis is confirmed experimentally, where the MoSAs-Mo2C assembled on NCNTs (MoSAs-Mo2C/NCNTs) yields an ammonia formation rate of 16.1 µg h−1 cmcat−2 at −0.25 V versus reversible hydrogen electrode, which is about four times that by the Mo2C alone (Mo2C/NCNTs) and 4.5 times that by the MoSAs alone (MoSAs/NCNTs). Moreover, the Faradic efficiency of the MoSAs-Mo2C/NCNTs is raised up to twofold and sevenfold of the Mo2C/NCNTs and MoSAs/NCNTs, respectively. The MoSAs-Mo2C/NCNTs also demonstrate outstanding stability by the almost unchanged catalytic performance over 10 h of the chronoamperometric test. The present study provides a promising new prototype of synchronizing the selectivity and activity for the multistep catalytic reactions. 相似文献
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Min Kuang Yu Wang Wei Fang Huiteng Tan Mengxin Chen Jiandong Yao Chuntai Liu Jianwei Xu Kun Zhou Qingyu Yan 《Advanced materials (Deerfield Beach, Fla.)》2020,32(26):2002189
A facile pathway of the electrocatalytic nitrogen oxidation reaction (NOR) to nitrate is proposed, and Ru-doped TiO2/RuO2 (abbreviated as Ru/TiO2) as a proof-of-concept catalyst is employed accordingly. Density functional theory (DFT) calculations suggest that Ruδ+ can function as the main active center for the NOR process. Remarkably doping Ru into the TiO2 lattice can induce an upshift of the d-band center of the Ru site, resulting in enhanced activity for accelerating electrochemical conversion of inert N2 to active NO*. Overdoping of Ru ions will lead to the formation of additional RuO2 on the TiO2 surface, which provides oxygen evolution reaction (OER) active sites for promoting the redox transformation of the NO* intermediate to nitrate. However, too much RuO2 in the catalyst is detrimental to both the selectivity of the NOR and the Faradaic efficiency due to the dominant OER process. Experimentally, a considerable nitrate yield rate of 161.9 µmol h−1 gcat−1 (besides, a total nitrate yield of 47.9 µg during 50 h) and a highest nitrate Faradaic efficiency of 26.1% are achieved by the Ru/TiO2 catalyst (with the hybrid composition of RuxTiyO2 and extra RuO2 by 2.79 wt% Ru addition amount) in 0.1 m Na2SO4 electrolyte. 相似文献
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Chia‐Che Chang Sin‐Ren Li Hung‐Lung Chou Yi‐Cheng Lee Shivaraj Patil Ying‐Sheng Lin Chun‐Chih Chang Yuan Jay Chang Di‐Yan Wang 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(49)
The generation of ammonia, hydrogen production, and nitrogen purification are considered as energy intensive processes accompanied with large amounts of CO2 emission. An electrochemical method assisted by photoenergy is widely utilized for the chemical energy conversion. In this work, earth‐abundant iron pyrite (FeS2) nanocrystals grown on carbon fiber paper (FeS2/CFP) are found to be an electrochemical and photoactive catalyst for nitrogen reduction reaction under ambient temperature and pressure. The electrochemical results reveal that FeS2/CFP achieves a high Faradaic efficiency (FE) of ≈14.14% and NH3 yield rate of ≈0.096 µg min?1 at ?0.6 V versus RHE electrode in 0.25 m LiClO4. During the electrochemical catalytic reaction, the crystal structure of FeS2/CFP remains in the cubic pyrite phase, as analyzed by in situ X‐ray diffraction measurements. With near‐infrared laser irradiation (808 nm), the NH3 yield rate of the FeS2/CFP catalyst can be slightly improved to 0.1 µg min?1 with high FE of 14.57%. Furthermore, density functional theory calculations demonstrate that the N2 molecule has strong chemical adsorption energy on the iron atom of FeS2. Overall, iron pyrite‐based materials have proven to be a potential electrocatalyst with photoactive behavior for ammonia production in practical applications. 相似文献
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James A. Behan Eric Mates‐Torres Serban N. Stamatin Carlota Domínguez Alessandro Iannaci Karsten Fleischer Md. Khairul Hoque Tatiana S. Perova Max García‐Melchor Paula E. Colavita 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(48)
Metal‐free carbon electrodes with well‐defined composition and smooth topography are prepared via sputter deposition followed by thermal treatment with inert and reactive gases. X‐ray photoelectron spectroscopy (XPS) and Raman spectroscopy show that three carbons of similar N/C content that differ in N‐site composition are thus prepared: an electrode consisting of almost exclusively graphitic‐N (NG), an electrode with predominantly pyridinic‐N (NP), and one with ≈1:1 NG:NP composition. These materials are used as model systems to investigate the activity of N‐doped carbons in the oxygen reduction reaction (ORR) using voltammetry. Results show that selectivity toward 4e‐reduction of O2 is strongly influenced by the NG/NP site composition, with the material possessing nearly uniform NG/NP composition being the only one yielding a 4e‐reduction. Computational studies on model graphene clusters are carried out to elucidate the effect of N‐site homogeneity on the reaction pathway. Calculations show that for pure NG‐doping or NP‐doping of model graphene clusters, adsorption of hydroperoxide and hydroperoxyl radical intermediates, respectively, is weak, thus favoring desorption prior to complete 4e‐reduction to hydroxide. Clusters with mixed NG/NP sites display synergistic effects, suggesting that co‐presence of these sites improves activity and selectivity by achieving high theoretical reduction potentials while facilitating retention of intermediates. 相似文献
18.
Biomass Derived N‐Doped Porous Carbon Supported Single Fe Atoms as Superior Electrocatalysts for Oxygen Reduction
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Zhengping Zhang Xinjin Gao Meiling Dou Jing Ji Feng Wang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(22)
Exploring sustainable and high‐performance electrocatalysts for the oxygen reduction reaction (ORR) is the crucial issue for the large‐scale application of fuel cell technology. A new strategy is demonstrated to utilize the biomass resource for the synthesis of N‐doped hierarchically porous carbon supported single‐atomic Fe (SA‐Fe/NHPC) electrocatalyst toward the ORR. Based on the confinement effect of porous carbon and high‐coordination natural iron source, SA‐Fe/NHPC, derived from the hemin‐adsorbed bio‐porphyra‐carbon by rapid heat‐treatment up to 800 °C, presents the atomic dispersion of Fe atoms in the N‐doped porous carbon. Compared with the molecular hemin and nanoparticle Fe samples, the as‐prepared SA‐Fe/NHPC exhibits a superior catalytic activity (E 1/2 = 0.87 V and J k = 4.1 mA cm?2, at 0.88 V), remarkable catalytic stability (≈1 mV negative shift of E 1/2, after 3000 potential cycles), and outstanding methanol‐tolerance, even much better than the state‐of‐the‐art Pt/C catalyst. The sustainable and effective strategy for utilizing biomass to achieve high‐performance single‐atom catalysts can also provide an opportunity for other catalytic applications in the atomic scale. 相似文献
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Hui Xu Jing Wu Wei Luo Qin Li Weixian Zhang Jianping Yang 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(30)
Electrocatalysis for nitrate reduction reaction (NRR) has recently been recognized as a promising technology to convert nitrate to nitrogen. Catalyst support plays an important role in electrocatalytic process. Although porous carbon and metal oxides are considered as common supports for metal‐based catalysts, fabrication of such architecture with high electric conductivity, uniform dispersion of nanoparticles, and long‐term catalytic stability through a simple and feasible approach still remains a significant challenge. Herein, inspired by the signal transfer mode of dendritic cell, an all‐carbon dendritic cell‐like (DCL) architecture comprising mesoporous carbon spheres (MCS) connected by tethered carbon nanotubes (CNTs) with CuPd nanoparticles dispersed throughout (CuPd@DCL‐MCS/CNTs) is reported. An impressive removal capacity as high as 22 500 mg N g?1 CuPd (≈12 times superior to Fe‐based catalysts), high nitrate conversion (>95%) and nitrogen selectivity (>95%) are achieved under a low initial concentration of nitrate (100 mg L?1) when using an optimized‐NRR electrocatalyst (4CuPd@DCL‐MCS/CNTs). Remarkably, nitrate conversion and nitrogen selectivity are both close to 100% in an ultralow concentration of 10 mg L?1, meeting drinking water standard. The present work not only provides high electrocatalytic performance for NRR but also introduces new inspiration for the preparation of other DCL‐based architectures. 相似文献