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The electrochemical splitting of water for hydrogen production faces a major challenge due to its anodic oxygen evolution reaction (OER), necessitating research on the rational design and facile synthesis of OER catalysts to enhance catalytic activity and stability. This study proposes a ligand-induced MOF-on-MOF approach to fabricate various trimetallic MnFeCo-based Prussian blue analog (PBA) nanostructures. The addition of [Fe(CN) 6 ] 3- transforms them from cuboids with protruding corners (MnFeCoPBA-I) to core-shell configurations (MnFeCoPBA-II), and finally to hollow structures (MnFeCoPBA-III). After pyrolysis at 800 °C, they are converted into corresponding PBA-derived carbon nanomaterials, featuring uniformly dispersed Mn 2 Co 2 C nanoparticles. A comparative analysis demonstrates that the Fe addition enhances catalytic activity, while Mn-doped materials exhibit excellent stability. Specifically, the optimized MnFeCoNC-I-800 demonstrates outstanding OER performance in 1.0 m KOH solution, with an overpotential of 318 mV at 10 mA cm -2 , maintaining stability for up to 150 h. Theoretical calculations elucidate synergistic interactions between Fe dopants and the Mn 2 Co 2 C matrix, reducing barriers for oxygen intermediates and improving intrinsic OER activity. These findings offer valuable insights into the structure-morphology relationships of MOF precursors, advancing the development of highly active and stable MOF-derived OER catalysts for practical applications., (© 2024 The Authors. Advanced Science published by Wiley‐VCH GmbH.)

Water splitting technology can convert renewable energies such as solar and wind into hydrogen energy, which is key to achieving a low-carbon hydrogen economy cycle. However, Pt-based catalysts for hydrogen evolution reaction (HER) are too expensive, thus it needs to develop efficient non-noble metal catalysts as alternatives. Herein, Ni-BDC-loaded carbon cloth (CC) is co-pyrolyzed with urea to obtain a composite structure of carbon nanotubes (CNT) and porous carbon (PC) embedded with W-doped Ni nanoparticles on CC, resulting in NiW-CNT/PC/CC. Benefiting from the synergistic effect between Ni and W, the high conductivity of CNT, and the high mass transfer rate of PC, NiW-CNT/PC/CC exhibits excellent HER activity in KOH, which only requires a low overpotential of 45 mV to drive a current density of 10 mA cm -2 with stability exceeding 40 h. Simulation calculations confirm that the W doping in metal Ni can optimize its electronic structure by lowering the d-band center and weakening hydrogen adsorption, thus reducing its HER barrier., (© 2024 Wiley‐VCH GmbH.)

The electrocatalytic conversion of nitrate (NO 3 - ) to NH 3 (NO 3 RR) at ambient conditions offers a promising alternative to the Haber-Bosch process. The pivotal factors in optimizing the proficient conversion of NO 3 - into NH 3 include enhancing the adsorption capabilities of the intermediates on the catalyst surface and expediting the hydrogenation steps. Herein, the Cu/Cu 2 O/Pi NWs catalyst is designed based on the directed-evolution strategy to achieve an efficient reduction of NO 3 ‾. Benefiting from the synergistic effect of the O V -enriched Cu 2 O phase developed during the directed-evolution process and the pristine Cu phase, the catalyst exhibits improved adsorption performance for diverse NO 3 RR intermediates. Additionally, the phosphate group anchored on the catalyst's surface during the directed-evolution process facilitates water electrolysis, thereby generating H ads on the catalyst surface and promoting the hydrogenation step of NO 3 RR. As a result, the Cu/Cu 2 O/Pi NWs catalyst shows an excellent FE for NH 3 (96.6%) and super-high NH 3 yield rate of 1.2 mol h -1  g cat. -1 in 1 m KOH and 0.1 m KNO 3 solution at -0.5 V versus RHE. Moreover, the catalyst's stability is enhanced by the stabilizing influence of the phosphate group on the Cu 2 O phase. This work highlights the promise of a directed-evolution approach in designing catalysts for NO 3 RR., (© 2024 Wiley‐VCH GmbH.)

Metal-organic frameworks (MOFs), as a subclass of porous crystalline materials with unique structures and multifunctional properties, play a pivotal role in various research domains. In recent years, significant attention has been directed toward composite materials based on MOFs, particularly MOF-on-MOF heterostructures. Compared to individual MOF materials, MOF-on-MOF structures harness the distinctive attributes of two or more different MOFs, enabling synergistic effects and allowing for the tailored design of diverse multilayered architectures to expand their application scope. However, the rational design and facile synthesis of MOF-on-MOF composite materials are in principle challenging due to the structural diversity and the intricate interfaces. Hence, this review primarily focuses on elucidating the factors that influence their interfacial growth, with a specific emphasis on the interfacial engineering of heterogeneous reactions, in which MOF-on-MOF hybrids can be conveniently obtained by using pre-fabricated MOF precursors. These factors are categorized as internal and external elements, encompassing inorganic metals, organic ligands, lattice matching, nucleation kinetics, thermodynamics, etc. Meanwhile, these intriguing MOF-on-MOF materials offer a wide range of advantages in various application fields, such as adsorption, separation, catalysis, and energy-related applications. Finally, this review highlights current complexities and challenges while providing a forward-looking perspective on future research directions., (© 2023 Wiley‐VCH GmbH.)

Metal-organic frameworks (MOFs) represent a relatively new family of materials that attract lots of attention thanks to their unique features such as hierarchical porosity, active metal centers, versatility of linkers/metal nodes, and large surface area. Among the extended list of MOFs, Zr-based-MOFs demonstrate comparably superior chemical and thermal stabilities, making them ideal candidates for energy and environmental applications. As a Zr-MOF, NU-1000 is first synthesized at Northwestern University. A comprehensive review of various approaches to the synthesis of NU-1000 MOFs for obtaining unique surface properties (e.g., diverse surface morphologies, large surface area, and particular pore size distribution) and their applications in the catalysis (electro-, and photo-catalysis), CO 2 reduction, batteries, hydrogen storage, gas storage/separation, and other environmental fields are presented. The review further outlines the current challenges in the development of NU-1000 MOFs and their derivatives in practical applications, revealing areas for future investigation., (© 2023 The Authors. Small published by Wiley‐VCH GmbH.)

The electrocatalytic conversion of nitrate (NO 3 ‾) to NH 3  (NO 3 RR) offers a promising alternative to the Haber-Bosch process. However, the overall kinetic rate of NO 3 RR is plagued by the complex proton-assisted multiple-electron transfer process. Herein, Ag/Co 3 O 4 /CoOOH nanowires (i-Ag/Co 3 O 4  NWs) tandem catalyst is designed to optimize the kinetic rate of intermediate reaction for NO 3 RR simultaneously. The authors proved that NO 3 ‾ ions are reduced to NO 2 ‾ preferentially on Ag phases and then NO 2 ‾ to NO on Co 3 O 4  phases. The CoOOH phases catalyze NO reduction to NH 3  via NH 2 OH intermediate. This unique catalyst efficiently converts NO 3 ‾ to NH 3  through a triple reaction with a high Faradaic efficiency (FE) of 94.3% and a high NH 3  yield rate of 253.7 μmol h -1  cm -2  in 1 M KOH and 0.1 M KNO 3  solution at -0.25 V versus RHE. The kinetic studies demonstrate that converting NH 2 OH into NH 3  is the rate-determining step (RDS) with an energy barrier of 0.151 eV over i-Ag/Co 3 O 4  NWs. Further applying i-Ag/Co 3 O 4  NWs as the cathode material, a novel Zn-nitrate battery exhibits a power density of 2.56 mW cm -2  and an FE of 91.4% for NH 3  production., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

The photocatalytic transformation of carbon dioxide (CO 2 ) into carbon-based fuels or chemicals using sustainable solar energy is considered an ideal strategy for simultaneously alleviating the energy shortage and environmental crises. However, owing to the low energy utilization of sunlight and inferior catalytic activity, the conversion efficiency of CO 2 photoreduction is far from satisfactory. In this study, a MOF-derived hollow bimetallic oxide nanomaterial is prepared for the efficient photoreduction of CO 2 . First, a unique ZIF-67-on-InOF-1 heterostructure is successfully obtained by growing a secondary Co-based ZIF-67 onto the initial InOF-1 nanorods. The corresponding hollow counterpart has a larger specific surface area after acid etching, and the oxidized bimetallic H-Co 3 O 4 /In 2 O 3 material exhibits abundant heterogeneous interfaces that expose more active sites. The energy band structure of H-Co 3 O 4 /In 2 O 3 corresponds well with the photosensitizer of [Ru(bpy) 3 ]Cl 2 , which results in a high CO yield of 4828 ± 570 µmol h -1  g -1 and stable activity over a consecutive of six runs, demonstrating adequate photocatalytic performance. This study demonstrates that the rational design of MOF-on-MOF heterostructures can completely exploit the synergistic effects between different components, which may be extended to other MOF-derived nanomaterials as promising catalysts for practical energy conversion and storage., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

IrO 2 as benchmark electrocatalyst for acidic oxygen evolution reaction (OER) suffers from its low activity and poor stability. Modulating the coordination environment of IrO 2 by chemical doping is a methodology to suppress Ir dissolution and tailor adsorption behavior of active oxygen intermediates on interfacial Ir sites. Herein, the Re-doped IrO 2 with low crystallinity is rationally designed as highly active and robust electrocatalysts for acidic OER. Theoretical calculations suggest that the similar ionic sizes of Ir and Re impart large spontaneous substitution energy and successfully incorporate Re into the IrO 2 lattice. Re-doped IrO 2 exhibits a much larger migration energy from IrO 2 surface (0.96 eV) than other dopants (Ni, Cu, and Zn), indicating strong confinement of Re within the IrO 2 lattice for suppressing Ir dissolution. The optimal catalysts (Re: 10 at%) exhibit a low overpotential of 255 mV at 10 mA cm -2 and a high stability of 170 h for acidic OER. The comprehensive mechanism investigations demonstrate that the unique structural arrangement of the Ir active sites with Re-dopant imparts high performance of catalysts by minimizing Ir dissolution, facilitating *OH adsorption and *OOH deprotonation, and lowering kinetic barrier during OER. This study provides a methodology for designing highly-performed catalysts for energy conversion., (© 2023 Wiley-VCH GmbH.)

Using petrol to supply energy for a car or burning coal to heat a building generates plenty of greenhouse gas (GHG) emissions, including carbon dioxide (CO 2 ), water vapor (H 2 O), methane (CH 4 ), nitrous oxide (N 2 O), ozone (O 3 ), fluorinated gases. These up-and-coming metal-organic frameworks (MOFs) are structurally endowed with rigid inorganic nodes and versatile organic linkers, which have been extensively used in the GHG-related applications to improve the lives and protect the environment. Porous MOF materials and their derivatives have been demonstrated to be competitive and promising candidates for GHG separation, storage and conversions as they shows facile preparation, large porosity, adjustable nanostructure, abundant topology, and tunable physicochemical property. Enormous progress has been made in GHG storage and separation intrinsically stemmed from the different interaction between guest molecule and host framework from MOF itself in the recent five years. Meanwhile, the use of porous MOF materials to transform GHG and the influence of external conditions on the adsorption performance of MOFs for GHG are also enclosed. In this review, it is also highlighted that the existing challenges and future directions are discussed and envisioned in the rational design, facile synthesis and comprehensive utilization of MOFs and their derivatives for practical applications., (© 2022 Wiley-VCH GmbH.)

Solid catalyst is widely recognized as an effective strategy to control the chirality of single-walled carbon nanotubes (SWNTs). However, it is still not compatible with high density in horizontal arrays. "Trojan" catalysts strategy is one of the most effective methods to realize SWNTs with high density and has great potential in chirality control. Here, the co-realization of high density and chirality controlling for SWNTs in a low-temperature growth process is reported based on the developed solid "Trojan" catalyst. High temperature "Trojan" catalyst formation process provides sufficient catalyst number to acquire high density. These liquid "Trojan" catalysts are cooled to solid state by adopting low growth temperature (540 °C), which can be good template to realize the chirality controlling of SWNTs with exposing six-fold symmetry face, (111). Finally, (9, 6) and (13, 1) SWNTs enriched horizontal array with the purity of ≈90% and density of 4 tubes µm -1 is realized. The comparison between the distribution of initial catalysts and the density of as-grown tubes indicates no sacrificing on catalysts number to improve chirality selectivity. This work opens a new avenue on the catalyst's design and chirality controlling in SWNTs growth., (© 2022 Wiley-VCH GmbH.)

The exploration of non-noble metal electrocatalysts with high catalytic activity and stability for oxygen evolution reaction (OER) has become particularly urgent. Here, FeNi-based Prussian blue analogues (PBAs) were obtained by adding different solvents, where PBA particles preferentially grew on the surface plane/edge of coordination polymer precursor (Ni-ABDC) with various polarities. This resulted in the formation of FeNi-PBA-plane/edge morphologies, respectively. Notably, on account of more exposed PBAs, FeNi nanoparticles were uniformly supported on the porous N-doped carbon nanomaterials. Among them, the calcined FeNi-NC-800 underwent an interesting pre-activation process and exhibited a low overpotential of 281 mV at 10 mA cm -2 and a small Tafel slope of 82 mV dec -1 in 1.0 m KOH. This bimetallic sample showed superior OER activity and stability in comparison with control materials, which could be attributed to its abundant FeNi nanoparticles, high nitrogen content, large specific surface area, and synergistic effects between Fe and Ni atoms. In addition, relevant theoretical calculation on the optimal catalyst, FeNi-NC-800, further demonstrated its efficient OER performance with effective Fe-doping in the Ni-based oxyhydroxides., (© 2022 Wiley-VCH GmbH.)

Hollow carbon materials are regarded as crucial support materials in catalysis and electrochemical energy storage on account of their unique porous structure and electrical properties. Herein, an indium-based organic framework of InOF-1 can be thermally carbonized under inert argon to form indium particles through the redox reaction between nanosized indium oxide and carbon matrix. In particular, a type of porous hollow carbon nanostraw (HCNS) is in situ obtained by combining the fusion and removal of indium within the decarboxylation process. The as-synthesized HCNS, which possesses more charge active sites, short and quick electron, and ion transport pathways, has become an excellent carrier for electrochemically active species such as iodine with its unique internal cavity and interconnected porous structure on the tube wall. Furthermore, the assembled zinc-iodine batteries (ZIBs) provide a high capacity of 234.1 mAh g -1 at 1 A g -1 , which ensures that the adsorption and dissolution of iodine species in the electrolyte reach a rapid equilibrium. The rate and cycle performance of the HCNS-based ZIBs are greatly improved, thereby exhibiting an excellent capacity retention rate. It shows a better electrochemical exchange capacity than typical unidirectional carbon nanotubes, making HCNS an ideal cathode material for a new generation of high-performance batteries., (© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Great efforts have been devoted to searching for efficient catalytic systems to produce ultra-high density single-walled carbon nanotube (SWNT) arrays, which lay the foundation for future electronic devices. However, one major obstacle for realizing high-density surface-aligned SWNT arrays is the poor stability of metal nanoparticles in chemical vapor deposition catalytic processes. Recently, Trojan catalyst has been reported to yield unprecedented high-density SWNT arrays with 130 SWNTs per µm on the a-plane (11-20) of the sapphire substrate. Herein, a concept of catalyst confinement effect is put forward to revealing the secret of remarkable growth efficiency of SWNT arrays by Trojan catalyst. Combined experimental and theoretical studies indicate that confinement of catalyst nanoparticles on discrete a-plane strips plays a key role in stabilizing the small nanoparticles. The highly dispersive and active states of catalysts are maintained, which promote the growth of super-dense SWNT arrays. By rationally designing the substrate reconstruction process, large areas of dense SWNT arrays (130 SWNTs per µm) covering the entire substrate are obtained. This approach may provide novel ideas for the synthesis of various high-density 1D nanomaterials., (© 2021 Wiley-VCH GmbH.)

Multiporous metal-organic frameworks (MOFs) have emerged as a subclass of highly crystalline inorganic-organic materials, which are endowed with high surface areas, tunable pores, and fascinating nanostructures. Heterostructured MOF-on-MOF composites are recently becoming a research hotspot in the field of chemistry and materials science, which focus on the assembly of two or more different homogeneous or heterogeneous MOFs with various structures and morphologies. Compared with one single MOF, the dual MOF-on-MOF composites exhibit unprecedented tunability, hierarchical nanostructure, synergistic effect, and enhanced performance. Due to the difference of inorganic metals and organic ligands, the lattice parameters in a, b, and c directions in the single crystal cells could bring about subtle or large structural difference. It will result in the composite material with distinct growth methods to obtain secondary MOF grown from the initial MOF. In this review, the authors wish to mainly outline the latest synthetic strategies of heterostructured MOF-on-MOFs and their derivatives, including ordered epitaxial growth, random epitaxial growth, etc., which show the tutorial guidelines for the further development of various MOF-on-MOFs., (© 2021 Wiley-VCH GmbH.)

Low-cost heteroatom-doped carbon nanomaterials have been widely studied for efficient oxygen reduction reaction and energy storage and conversion in metal-air batteries. A Masson pine twigs-like 3-dimensional network construction of carbon nanofibers (CNFs) with abundant straight long Co, N, and S-doped carbon nanotubes (CNTs) is developed by thermal treatment of Co-based polymer coated onto polyacrylonitrile nanofiber network together with thiourea at 900 °C, denoted as CNFT-Co 9 S 8 -900. It is interesting to note that the introduction of a high concentration of sulfur does not lead to the complete toxicity of catalysts, but promotes the axial growth to selectively form straight CNTs instead of curly bamboo-like CNTs. The highly graphitized in-situ grown Co, N, S-doped CNTs and the 3-dimensional N-doped CNF network provide both active catalytic sites and highly conductive paths, which are beneficial for oxygen reduction reaction (ORR). Thus, the optimal CNFT-Co 9 S 8 -900 performs the excellent ORR catalytic activity with a half-wave potential of 0.84 V and a diffusion-limited current density of 5.49 mA cm -2 . Furthermore, the CNFT-Co 9 S 8 -900-based Zn-air devices also possess a high power density of 136.9 mW cm -2 better than commercial Pt/C., (© 2021 Wiley-VCH GmbH.)

In the preparation of nanomaterials, the kinetics and thermodynamics in the reaction can significantly affect the structures and phases of nanocrystals. Therefore, people are keen to adopt various synthetic strategies to accurately assemble the target nanocrystals, and reveal the underlying mechanism of the formation of specific structures. In this work, the total reaction time is adjusted to let the prepared MnCo Prussian blue analogous (MnCoPBA) crystals show four evolving morphological changes at different stages with the assistance of sodium dodecyl sulfate. Furthermore, it is clearly observed that the epitaxial growth along the (100) plane on the shell of MnCoPBA nanocrystals is favored, and the thermodynamics and kinetics in the morphology change process are analyzed in detail. Through the simple pyrolysis, MnCoPBA crystals can be successfully converted into the corresponding carbon composites, of which Mn 2 Co 2 C nanoparticles are evenly distributed in highly graphitized carbon matrix. Among them, PBA-III-700 performs good oxygen reduction reaction performance in alkaline solution with the half-wave potential of 0.801 V and diffusion-limited current density of 5.36 mA cm -2 , and its zinc-air battery exhibits the peak power density of 103.4 mW cm -2 competitive with commercial Pt/C., (© 2020 Wiley-VCH GmbH.)

Water electrolysis is an emerging energy conversion technology, which is significant for efficient hydrogen (H 2 ) production. Based on the high-activity transition metal ions and metal alloys of ultrastable bifunctional catalyst, the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are the key to achieving the energy conversion method by overall water splitting (OWS). This study reports that the Co-based coordination polymer (ZIF-67) anchoring on an indium-organic framework (InOF-1) composite (InOF-1@ZIF-67) is treated followed by carbonization and phosphorization to successfully obtain CoP nanoparticles-embedded carbon nanotubes and nitrogen-doped carbon materials (CoP-InNC@CNT). As HER and OER electrocatalysts, it is demonstrated that CoP-InNC@CNT simultaneously exhibit high HER performance (overpotential of 153 mV in 0.5 m H 2 SO 4 and 159 mV in 1.0 m KOH) and OER performance (overpotential of 270 mV in 1.0 m KOH) activities to reach the current density of 10 mA cm -2 . In addition, these CoP-InNC@CNT rods, as a cathode and an anode, can display an excellent OWS performance with η 10 = 1.58 V and better stability, which shows the satisfying electrocatalyst for the OWS compared to control materials. This method ensures the tight and uniform growth of the fast nucleating and stable materials on substrate and can be further applied for practical electrochemical reactions., Competing Interests: The authors declare no conflict of interest., (© 2020 The Authors. Published by WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.)