Single‐atom catalysts are becoming a hot research topic owing to their unique characteristics of maximum specific activity and atomic utilization. Herein, a new single‐atom nanozyme (SAN) based on ...single Fe atoms anchored on N‐doped carbons supported on carbon nanotube (CNT/FeNC) is proposed. The CNT/FeNC with robust atomic Fe–Nx
moieties is synthesised, showing superior peroxidase‐like activity. Furthermore, the CNT/FeNC is used as the signal element in a series of paper‐based bioassays for ultrasensitive detection of H2O2, glucose, and ascorbic acid. The SAN provides a new type of signal element for developing various biosensing techniques.
A new single atom nanozyme (SAN), carbon nanotube supported single Fe atoms anchored on N‐doped carbon (CNT/FeNC), was developed for bioanalytical applications. The CNT/FeNC with robust atomic Fe–Nx
moieties showed superior peroxidase‐like activity. A series of paper based bioassays were developed using SAN as the signal element.
Metal–organic frameworks (MOFs) and their derivatives, featuring unique 3D microstructures and enhanced electromagnetic properties, are illuminating infinite possibilities for electromagnetic ...functional materials and devices, receiving significant attention from domestic and foreign researchers. Herein, the design strategy of the MOF monomer is investigated, and the electromagnetic response mechanism is systematically analyzed. Research is emphatically introduced regarding MOF‐based materials in microwave absorption and electromagnetic interference shielding. Finally, a clear insight on the quickly growing field is given, and the current challenges and future research directions are summarized and predicted.
The research progress of metal–organic framework‐based materials in microwave absorption and electromagnetic interference shielding has refreshed the understanding of the material world, which stimulates the combination of science and technology, lighting up the development direction of electromagnetic functional materials and devices in the future.
The great interest in rechargeable Zn–air batteries (ZABs) arouses extensive research on low‐cost, high‐active, and durable bifunctional electrocatalysts to boost the sluggish oxygen reduction ...reaction (ORR) and oxygen evolution reaction (OER). It remains a great challenge to simultaneously host high‐active and independent ORR and OER sites in a single catalyst. Herein a dual‐phasic carbon nanoarchitecture consisting of a single‐atom phase for the ORR and nanosized phase for the OER is proposed. Specifically, single Co atoms supported on carbon nanotubes (single‐atom phase) and nanosized Co encapsulated in zeolitic‐imidazole‐framework‐derived carbon polyhedron (nanosized phase) are integrated together via carbon nanotube bridges. The obtained dual‐phasic carbon catalyst shows a small overpotential difference of 0.74 V between OER potential at 10 mA cm−2 and ORR half‐wave potential. The ZAB based on the bifunctional catalyst demonstrates a large power density of 172 mW cm−2. Furthermore, it shows a small charge‐discharge potential gap of 0.51 V at 5 mA cm−2 and outstanding discharge‐charge cycling durability. This study provides a feasible design concept to achieve multifunctional catalysts and promotes the development of rechargeable ZABs.
A dual‐phasic carbon nanoarchitecture consisting of a single‐atom phase for oxygen reduction reaction (ORR) and nanosized phase for oxygen evolution reaction (OER) is proposed to boost the oxygen electrode performance for rechargeable Zn–air batteries, showing a small OER‐ORR overpotential difference (0.74 V), large power density (172 mW cm–2), a small charge‐discharge potential gap (0.51 V at 5 mA cm–2), and outstanding discharge‐charge cycling durability.
The rapid progress of proton exchange membrane fuel cells (PEMFCs) and alkaline exchange membrane fuel cells (AMFCs) has boosted the hydrogen economy concept via diverse energy applications in the ...past decades. For a holistic understanding of the development status of PEMFCs and AMFCs, recent advancements in electrocatalyst design and catalyst layer optimization, along with cell performance in terms of activity and durability in PEMFCs and AMFCs, are summarized here. The activity, stability, and fuel cell performance of different types of electrocatalysts for both oxygen reduction reaction and hydrogen oxidation reaction are discussed and compared. Research directions on the further development of active, stable, and low‐cost electrocatalysts to meet the ultimate commercialization of PEMFCs and AMFCs are also discussed.
The development of fuel cells is of great significance for achieving a sustainable society. Recent progress in cathodic electrocatalysts for proton exchange membrane fuel cells and anodic and cathodic electrocatalysts for alkaline exchange membrane fuel cells is summarized. The rational design strategies, structure evolution, activities, fuel cell performance, and durability of noble‐metal‐ and non‐noble‐metal‐based electrocatalysts are discussed.
Oxygen reduction reaction (ORR) is a key step that determines the performance of a variety of energy storage and conversion devices, such as fuel cells and metal–air batteries. Heteroatom‐doped ...carbon nanotubes (CNTs) and graphenes have attracted increasing interest and hold great promise as efficient ORR catalysts to replace noble‐metal‐based catalysts, owing to their unique structure characteristics, excellent physicochemical properties, low cost, and rich resources. In this review, recent progress on the design, fabrication, and performance of heteroatom‐doped CNT‐ and graphene‐based catalysts is summarized, aiming to provide insights into the working mechanism of these heteroatom‐doped nanocarbons in ORR. The advantages, challenges that remain, and possible solutions of these nanocarbon‐based electrocatalysts are discussed. Finally, future developing trends of the CNT‐ and graphene‐based ORR catalysts are proposed.
Carbon nanotubes (CNTs)/graphenes are unique one‐dimensional/two‐dimensional structures composed of sp2 hybridized carbon atoms and excellent physicochemical properties. Heteroatom‐doped CNT/graphene‐based catalysts show advantages of high‐content active sites, good electron/ion transport capability, excellent durability, and low cost. These catalysts demonstrate attractive oxygen reduction reaction performance and therefore may find applications in metal–air batteries and fuel cells.
Single-atom catalysts (SACs) and single-cluster catalysts (SCCs) are the new frontier of heterogeneous catalysis, which exhibit high activity, selectivity, stability, and atomic efficiency as well as ...precise tunability. However, the lack of efficient methods for producing high-loading and high-purity SACs and SCCs hinders their industrial applications. In this work, we propose a general and efficient strategy for the production of high-loading and high-purity SACs and SCCs anchored on suitable substrates. Our strategy relies on the existence of an electrochemical potential window (EcPW) we predict within which any aggregate forms of the target metal on the substrate are leached away by electrochemical oxidation, while the strongly bound single atoms or single clusters remain at the substrate. We demonstrate the applicability of this strategy with modeling the production of Pt, Pd, and Ni SACs anchored on N-doped graphene and Fe2O3 as well as Pt3 and Ni3 SCCs anchored on graphdiyne.
Low‐dimensional materials have been long sought after for their particular electromagnetic (EM) functions, with promising applications in EM wave absorbing and shielding, communicating and imaging, ...sensing and detecting, driving and actuating, etc. Herein, across the whole EM spectrum, low‐dimensional EM functional materials and devices are highly focused on. The crystal engineering and function‐guiding features addressed relate to crystal and electronic structures, EM responses and properties, energy conversion, as well as EM wave absorbing and shielding. Moreover, insight is given into this rapidly broadening field, the main challenges are proposed and future directions are predicted.
Electromagnetic response and energy conversion for functions and devices of low‐dimensional materials are systematically summarized. The crystal and electronic structures are described, and crystal engineering and function‐guiding features are highlighted. Importantly, the electromagnetic functions and devices are demonstrated with a prediction of the most prospective opportunities and directions for the future.
Abstract The current industrial ammonia synthesis relies on Haber–Bosch process that is initiated by the dissociative mechanism, in which the adsorbed N 2 dissociates directly, and thus is limited by ...Brønsted–Evans–Polanyi (BEP) relation. Here we propose a new strategy that an anchored Fe 3 cluster on the θ-Al 2 O 3 (010) surface as a heterogeneous catalyst for ammonia synthesis from first-principles theoretical study and microkinetic analysis. We have studied the whole catalytic mechanism for conversion of N 2 to NH 3 on Fe 3 /θ-Al 2 O 3 (010), and find that an associative mechanism, in which the adsorbed N 2 is first hydrogenated to NNH, dominates over the dissociative mechanism, which we attribute to the large spin polarization, low oxidation state of iron, and multi-step redox capability of Fe 3 cluster. The associative mechanism liberates the turnover frequency (TOF) for ammonia production from the limitation due to the BEP relation, and the calculated TOF on Fe 3 /θ-Al 2 O 3 (010) is comparable to Ru B5 site.
The development of highly efficient and robust bifunctional electrocatalysts for oxygen reduction (ORR) and evolution reactions (OER) is the key issue for realizing high‐performance and long‐life ...rechargeable zinc–air batteries (ZABs). However, it is still a great challenge to integrate independent ORR and OER sites in a catalyst with high activity. Here, a carbon nanotube‐bridging strategy is proposed to synthesize such a bifunctional oxygen electrocatalyst enriched with highly active single‐atom Fe sites for the ORR and high‐performance nanosized NiCo hydroxides for the OER. Consequently, the developed catalyst shows a small overpotential difference of 0.686 V. When used as an oxygen electrode catalyst, the corresponding ZAB exhibits a large power density of 219.5 mW cm−2, a small charge–discharge voltage gap of 0.72 V at 10 mA cm−2, and outstanding discharge–charge durability without attenuation after more than 700 cycles. This work proposes a new idea to realize multifunctional catalysts and drives the practical application of ZABs.
A bifunctional oxygen electrocatalyst is designed by a carbon nanotube–bridged strategy enriched with ultrahigh–activity single–atom Fe sites and nanosized NiCo hydroxides for excellent oxygen reduction and evolution. Such a bifunctional oxygen electrocatalyst assembled rechargeable zinc‐air batters exhibit a large power density, a small charge‐discharge voltage gap, and outstanding discharge‐charge durability.
The lifespan of high‐energy‐density lithium metal batteries (LMBs) is hindered by heterogeneous solid electrolyte interphase (SEI). The rational design of electrolytes is strongly considered to ...obtain uniform SEI in working batteries. Herein, a modification of nitrate ion (NO3−) is proposed and validated to improve the homogeneity of the SEI in practical LMBs. NO3− is connected to an ether‐based moiety to form isosorbide dinitrate (ISDN) to break the resonance structure of NO3− and improve the reducibility. The decomposition of non‐resonant −NO3 in ISDN enriches SEI with abundant LiNxOy and induces uniform lithium deposition. Lithium–sulfur batteries with ISDN additives deliver a capacity retention of 83.7 % for 100 cycles compared with rapid decay with LiNO3 after 55 cycles. Moreover, lithium–sulfur pouch cells with ISDN additives provide a specific energy of 319 Wh kg−1 and undergo 20 cycles. This work provides a realistic reference in designing additives to modify the SEI for stabilizing LMBs.
The modification of NO3− is achieved by connecting NO3− to an ether‐based moiety. The broken resonance structure of −NO3 improves its reducibility compared with NO3−. The decomposition of −NO3 forms a LiNxOy‐rich solid electrolyte interphase (SEI) and induces uniform Li deposition.
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