Covalent Organic Frameworks Based Electrocatalysts for Two-Electron Oxygen Reduction Reaction: Design Principles, Recent Advances, and Perspective.

Hydrogen peroxide (H2O2) is an environmentally friendly oxidant with a wide range of applications, and the two-electron pathway (2e-) of the oxygen reduction reaction (ORR) for H2O2 production has attracted much attention due to its eco-friendly nature and operational simplicity in contrast to the conventional anthraquinone process. The challenge is to design electrocatalysts with high activity and selectivity and to understand their structure-activity relationship and catalytic mechanism in the ORR process. Covalent organic frameworks (COFs) provide an efficient template for the construction of highly efficient electrocatalysts due to their designable structure, excellent stability, and controllable porosity. This review firstly outlines the design principles of COFs, including the selection of metallic and nonmetallic active sites, the modulation of the electronic structure of the active sites, and the dimensionality modulation of the COFs, to provide guidance for improving the production performance of H2O2. Subsequently, representative results are summarized in terms of both metallic and metal-free sites to follow the latest progress. Moreover, the challenges and perspectives of 2e- ORR electrocatalysts based on COFs are discussed.

Clinical features, epidemiology, and treatment of Shwachman-Diamond syndrome: a systematic review.

BACKGROUND: Shwachman-Diamond syndrome (SDS) is an autosomal recessive disease which results in inherited bone marrow failure (IBMF) and is characterized by exocrine pancreatic dysfunction and diverse clinical phenotypes. In the present study, we reviewed the internationally published reports on SDS patients, in order to summarize the clinical features, epidemiology, and treatment of SDS. METHODS: We searched the WangFang and China National Knowledge Infrastructure databases with the keywords "Shwachman-Diamond syndrome," "SDS," "SBDS gene" and "inherited bone marrow failure" for relevant articles published from January 2002 to October 2022. In addition, studies published from January 2002 to October 2022 were searched from the Web of Science, PubMed, and MEDLINE databases, using "Shwachman-diamond syndrome" as the keyword. Finally, one child with SDS treated in Tongji Hospital was also included. RESULTS: The clinical features of 156 patients with SDS were summarized. The three major clinical features of SDS were found to be peripheral blood cytopenia (96.8%), exocrine pancreatic dysfunction (83.3%), and failure to thrive (83.3%). The detection rate of SDS mutations was 94.6% (125/132). Mutations in SBDS, DNAJC21, SRP54, ELF6, and ELF1 have been reported. The male-to-female ratio was approximately 1.3/1. The median age of onset was 0.16 years, but the diagnostic age lagged by a median age of 1.3 years. CONCLUSIONS: Pancreatic exocrine insufficiency and growth failure were common initial symptoms. SDS onset occurred early in childhood, and individual differences were obvious. Comprehensive collection and analysis of case-related data can help clinicians understand the clinical characteristics of SDS, which may improve early diagnosis and promote effective clinical intervention.

Phosphine-Based Covalent Organic Framework for the Controlled Synthesis of Broad-Scope Ultrafine Nanoparticles.

In this work, a phosphine-based covalent organic framework (Phos-COF-1) is successfully synthesized and employed as a template for the confined growth of broad-scope nanoparticles (NPs). Ascribed to the ordered distribution of phosphine coordination sites in the well-defined pores, various stable and well-dispersed ultrafine metal NPs including Pd, Pt, Au, and bimetallic PdAuNPs with narrow size distributions are successfully prepared as determined by transmission electron microscopy, X-ray photoelectron spectroscopy, inductively coupled plasma, and powder X-ray diffraction analyses. It is also demonstrated that the as-prepared Phos-COF-1-supported ultrafine NPs exhibit excellent catalytic activities and recyclability toward the Suzuki-Miyaura coupling reaction, reduction of nitro-phenol and 1-bromo-4-nitrobenzene, and even tandem coupling and reduction of p-nitroiodobenzene. This work will open many new possibilities for preparing COF-supported ultrafine NPs with good dispersity and stability for a broad range of applications.

Crystalline Lithium Imidazolate Covalent Organic Frameworks with High Li-Ion Conductivity.

Ionic covalent organic frameworks (ICOFs) have recently emerged as promising candidates for solid-state electrolytes. Herein, we report the first example of a series of crystalline imidazolate-containing ICOFs as single-ion conducting COF solid electrolyte materials, where lithium cations freely travel through the intrinsic channels with outstanding ion conductivity (up to 7.2 × 10-3 S cm-1) and impressively low activation energy (as low as 0.10 eV). These properties are attributed to the weak Li ion-imidazolate binding interactions and well-defined porous 2D framework structures of such ICOFs. We also investigated the structure-property relationship by varying the electronic properties of substituents (electron donating/withdrawing) that covalently attached to the imidazolate groups. We found electron-withdrawing substituents significantly improve the ion-conducting ability of imidazolate-ICOF by weakening ion-pair interactions. Our study provides a convenient bottom-up approach toward a novel class of highly efficient single-ion conducting ICOFs which could be used in all solid-state electrolytic devices.

Facile Synthesis of Sea-Urchin-Like Pt and Pt/Au Nanodendrites and Their Enhanced Electrocatalytic Properties.

This Communication demonstrates a novel and facial approach to achieving monodispersed sea-urchin-like Pt nanodendrites under a 1 bar hydrogen environment at 165 °C. These Pt nanodendrites can be further used as seeds for the formation of Pt/Au nanodendrites. Both Pt and Pt/Au nanodendrites exhibit the desired eletrocatalytic activities for the methanol oxidation reaction.

Evaluating the Efficacy and Anti-infective Effect of High-dose Intravenous Immunoglobulin Adjuvant Therapy for Acquired Aplastic Anemia Children.

BACKGROUND: The efficacy and anti-infective effect of high-dose intravenous immunoglobulin (HDIVIG) in severe or very severe aplastic anemia children were evaluated. PATIENTS AND METHODS: In total, 61 patients who underwent immunosuppressive therapy were retrospectively reviewed. The non-IVIG group (30 cases) received rabbit-antithymocyte protein (R-ATG, 3 to 5 mg/kg/d, for 5 consecutive days)+cyclosporin A (CSA), and the HDIVIG group (31 cases) underwent R-ATG+CSA+immunoglobulin (1 g/kg/d, for 2 consecutive days, once a month, 6 times). RESULTS: The early effective rate was higher in the HDIVIG group (P=0.020). However, the long-term effective rate and the 5-year overall survival rates difference were not statistically significant (P=0.717, 0.419). The infection rate and severe infection rate in the HDIVIG group were lower (P=0.003, 0.008). The infection-related mortality differences were not statistically significant after ATG application (P>0.05). In the HDIVIG group, 9 patients were nonresponders. Among the nonresponders, 8 patients' first-dose IVIG was given within 7 days before ATG. CONCLUSIONS: HDIVIG may increase the early effective rate and reduce early infection and serious infection for aplastic anemia children, but failed to reduce the infection-related mortality.

Synthesis of Ultrafine and Highly Dispersed Metal Nanoparticles Confined in a Thioether-Containing Covalent Organic Framework and Their Catalytic Applications.

Covalent organic frameworks (COFs) with well-defined and customizable pore structures are promising templates for the synthesis of nanomaterials with controllable sizes and dispersity. Herein, a thioether-containing COF has been rationally designed and used for the confined growth of ultrafine metal nanoparticles (NPs). Pt or Pd nanoparticles (Pt NPs and Pd NPs) immobilized inside the cavity of the COF material have been successfully prepared at a high loading with a narrow size distribution (1.7 ± 0.2 nm). We found the crystallinity of the COF support and the presence of thioether groups inside the cavities are critical for the size-controlled synthesis of ultrafine NPs. The as-prepared COF-supported ultrafine Pt NPs and Pd NPs show excellent catalytic activity respectively in nitrophenol reduction and Suzuki-Miyaura coupling reaction under mild conditions and low catalyst loading. More importantly, they are highly stable and easily recycled and reused without loss of their catalytic activities. Such COF-supported size-controlled synthesis of nanoparticles will open a new frontier on design and preparation of metal NP@COF composite materials for various potential applications, such as catalysis and development of optical and electronic materials.

Elevated Serum Interleukin-6 Predicts Favorable Response to Immunosuppressive Therapy in Children With Aplastic Anemia.

BACKGROUND: Immunosuppressive therapy (IST) is the standard treatment for aplastic anemia (AA) children who lack a sibling donor, but the clinical response rate to IST varies. Predictors of response to IST are valuable for stratifying AA patients and making clinical decisions. METHODS: The serum interleukin (IL)-6 levels of 41 AA patients were measured at the time of diagnosis and the response rate of the patients to IST was evaluated at 3, 6, and 12 months after IST. Receiver-operator characteristic (ROC) analysis was used to calculate the predictive value of initial IL-6 levels in determining response at 6 months after IST. RESULTS: The initial IL-6 levels were significant higher in responders than nonresponders at 6 months after IST (211.89 vs. 18.09 pg/mL; P=0.005), using 36.8 pg/mL as a threshold, there were 80% sensitivity and 81% specificity for discriminating responders and nonresponders to IST. Patients with initial high IL-6 level (>36.8 pg/mL) have favorable response rates than those with initial low IL-6 level (<36.8 pg/mL) at 3, 6, and 12 months after IST (P<0.01). CONCLUSION: High levels of IL-6 at the time of diagnosis predict a favorable response to IST in children with AA and this may be helpful for patient's stratification and clinical decisions.

Preparation of a γ-Fe2 O3 /Ag nanowire coaxial nanocable for high-performance lithium-ion batteries.

In this study, we report the design and synthesis of a silver nanowire-γ-Fe2 O3 coaxial nanocable architecture (Ag NWs@γ-Fe2 O3 nanocable) through mild oxidation of [Fe(CO)5 ] on the surface of silver nanowires followed by a calcination process. After optimization of the structural design, the Ag NWs@γ-Fe2 O3 nanocable could deliver superior lithium storage performance in terms of high reversible capacity, good rate performance, and excellent stability, such as a high reversible capacity of about 890 mA h g(-1) after 60 cycles at a current rate of 0.1 C (1.0 C=1005 mA g(-1) ). The reversible capacity remains as high as about 550 mA h g(-1) even at a high current rate of 2.0 C. This dramatic performance is mainly attributed to the smart coaxial design, which can not only alleviate the large volume change and prevent the aggregation of γ-Fe2 O3 nanoparticles, but also enables good conductivity and thus enhances fast charge transfer. The unique structural features of the Ag NWs@γ-Fe2 O3 nanocable represent a promising anode material in lithium-ion battery applications.

Volatile guest molecule mediated strategy to convert covalent organic framework into nitrogen, sulfur-doped carbon as metal-free oxygen reduction electrocatalysts.

Covalent organic framework (COF) derived metal-free carbon materials have emerged as promising electrocatalysts for the oxygen reduction reaction (ORR). Herein, a volatile guest molecule mediated-pyrolysis strategy was explored on a designed thiophene-rich and imine-linked COF. Through the modulation of guest mediators (iodine and sulfur), the properties of the as-obtained carbon materials can be well regulated. The optimized nitrogen and sulfur dual-doped carbon electrocatalyst demonstrates remarkable ORR activity with a half-wave potential of 0.87 V and impressive durability, with only an 8% current loss over 21 h. The corresponding assembled zinc-air battery has a comparable power density (60 mW cm-2) to that of the commercial Pt/C. It is proposed that the coexistence of the guest mediators iodine and sulfur in the channels of COFs could prevent the loss of N species. The enhanced N content and N/S ratio are assumed to be responsible for the ORR performance. This study puts forward a novel strategy to prepare COF-derived carbon materials mediated by volatile guest molecules, which may provide new insights into the development of metal-free ORR catalysts.

Organic iontronic memristors for artificial synapses and bionic neuromorphic computing.

To tackle the current crisis of Moore's law, a sophisticated strategy entails the development of multistable memristors, bionic artificial synapses, logic circuits and brain-inspired neuromorphic computing. In comparison with conventional electronic systems, iontronic memristors offer greater potential for the manifestation of artificial intelligence and brain-machine interaction. Organic iontronic memristive materials (OIMs), which possess an organic backbone and exhibit stoichiometric ionic states, have emerged as pivotal contenders for the realization of high-performance bionic iontronic memristors. In this review, a comprehensive analysis of the progress and prospects of OIMs is presented, encompassing their inherent advantages, diverse types, synthesis methodologies, and wide-ranging applications in memristive devices. Predictably, the field of OIMs, as a rapidly developing research subject, presents an exciting opportunity for the development of highly efficient neuro-iontronic systems in areas such as in-sensor computing devices, artificial synapses, and human perception.

Emerging electrospinning platform toward nanoparticle to single atom transformation for steering selectivity in ammonia synthesis.

The rising top-down synthetic methodologies for transition metal single-atom catalysts (SACs) require controlled movement of metal atoms through the substrates; however, their direct transportation towards the ideal carrier remains a huge challenge. Herein, we showed a "top down" strategy for Co nanoparticles (NPs) to Co SA transformation by employing electrospun carbon nanofibers (CNFs) as atom carriers. Under high-temperature conditions, the Co atoms migrate from the surfaces of Co NPs and are then anchored by the surrounding carbon to form a Co-C3O1 coordination structure. The synthesized Co SAs/CNF electrocatalyst exhibits excellent electrocatalytic nitrate reduction reaction (NO3RR) activity with an NH3 yield of 0.79 mmol h-1 cm-2 and Faraday efficiency (FE) of 91.3% at -0.7 V vs. RHE in 0.1 M KNO3 and 0.1 M K2SO4 electrolytes. The in situ electrochemical characterization suggests that the NOH pathway is preferred by Co SAs/CNFs, and *NO hydrogenation and deoxygenation easily occur on Co SAs due to the small adsorption energy between Co SAs and *NO, as calculated by theoretical calculations. It is revealed that a small energy barrier (0.45 eV) for the rate determining step (RDS) ranges from *NO to *NOH and a strong capability for inhibiting hydrogen evolution (HER) significantly promotes the NH3 selectivity and activity of Co SAs/CNFs.

Ensemble effects of high entropy alloy for boosting alkaline water splitting coupled with urea oxidation.

FeCoNiMoRu/CNFs exhibits a small potential of 1.43 V vs. RHE (100 mA cm-2) and superior stability for 90 h toward urea electro-oxidation (UOR). In situ electrochemical Raman results strongly demonstrate the ensemble effects of the various metal sites on improving the UOR activity by co-stabilizing the important intermediates. This work will open new directions in the application of high-entropy alloys for small molecule oxidation reactions.

Solid-phase synthesis of ultra-small CuMo solid solution alloy for efficient electroreduction CO2-to-C2+ production.

We report a fascinating solid-phase synthesis of ultra-small CuMo solid solution alloy nanoclusters (2.1 nm) anchored on electrospun carbon nanofibers (CuMo/CNFs). By tuning the weight ratio of Cu and Mo, the optimized Cu2Mo1/CNFs achieves excellent CO2RR performance with a high faradaic efficiency (FE) of 84.5% for C2+ products and an FEethanol of 75.7%. In situ characterization demonstrates that the Cu2Mo1 alloy can strengthen the adsorption of the crucial intermediate and promote C-C coupling, leading to high selectivity and efficiency for C2+ products.

Dual-phase B-doped FeCoNiCuPd high-entropy alloys for nitrogen electroreduction to ammonia.

Dual-phase B-doped FeCoNiCuPd high-entropy alloy (DP-B-HEA) nanoparticles were synthesized via a strategy involving thermodynamically driven solid-phase diffusion. The DP-B-HEA/CNFs showed an outstanding electrochemical N2 reduction reaction (NRR) performance with an ammonia yield of 24.8 µmol h-1 cm-2 and NH3 faradaic efficiency (FE) of 39.2%. The optimized electronic structures of the HEA resulting from B doping led to the enhanced NRR activity and selectivity.

Bimetallic palladium-copper nanoplates with optimized d-band center simultaneously boost oxygen reduction activity and methanol tolerance.

The methanol-poisoning of electrocatalysts at the cathodic part of direct methanol fuel cells (DMFCs) can severely degrade the overall efficiency. Therefore, engineering cathodic catalysts with outstanding oxygen reduction activity, and simultaneously, superior methanol tolerance is greatly desired. Herein, bimetallic palladium-copper (PdCu) nanoplates with the optimized d-band center are designed as promising cathodic catalysts for DMFCs. It shows outstanding oxygen reduction activity with a mass activity (MA) of 0.522 A mgPd-1 in alkaline electrolyte, overwhelming the benchmarked commercial Pt/C and Pd/C. Meanwhile, it has prominent stability with only 4.0 % loss in MA after continuous 20 K cycles. More importantly, the PdCu nanoplates are almost inert toward methanol oxidation and show excellent anti-methanol capability. The theoretical calculations reveal that the downshift of d-band center in PdCu nanoplates and the electronic interaction between Pd and Cu atoms could effectively lower the methanol adsorption energy, thus leading to enhanced methanol tolerance. This work highlights the important role of tuning the electronic structure and optimized geometry of electrocatalysts to simultaneously boost their oxygen reduction activity, stability, and methanol tolerance for their future application in DMFCs.

Competitive Trapping of Single Atoms onto a Metal Carbide Surface.

Controlling atomic adjustment of single-atom catalysts (SACs) can directly change its local configuration, regulate the energy barrier of intermediates, and further optimize reaction pathways. Herein, we report an atom manipulating process to synthesize Ni atoms stabilized on vanadium carbide (NiSA-VC) through a nanofiber-medium thermodynamically driven atomic migration strategy. Experimental and theoretical results systematically reveal the tunable migration pathway of Ni atom from Ni nanoparticles to neighboring N-doped carbon (NC) and finally to metal carbide that was obtained by regulating the competitive adsorption energies between VC and NC for capturing Ni atoms. For CO2-to-CO electroreduction, NiSA-VC exhibits an industrial current density of -180 mA cm-2 at -1.0 V vs reversible hydrogen electrode and the highest Faradaic efficiency for CO production (FECO) of 96.8% at -0.4 V vs RHE in a flow cell. Significant electron transfers occurring in NiSA-VC structures contribute to the activation of CO2, facilitate the reaction free energy, regulate *CO desorption as the rate-determining step, and promote the activity and selectivity. This study provides an understanding on how to design powerful SACs for electrocatalysis.

Constructing single atom sites on bipyridine covalent organic frameworks for selective electrochemical production of H2O2.

We developed a series of single atom catalysts (SACs) anchored on bipyridine-rich COFs. By tuning the active metal center, the optimal Py-Bpy-COF-Zn shows the highest selectivity of 99.1% and excellent stability toward H2O2 production via oxygen reduction, which can be attributed to the high *OOH dissociation barrier indicated by the theoretical calculations. As a proof of concept, it acts as a cathodic catalyst in a homemade Zn-air battery, together with efficient wastewater treatment.

Flexible and recyclable bio-based transient resistive memory enabled by self-healing polyimine membrane.

The recyclable, self-healing and easily-degradable transient electronic technology has aroused tremendous attention in flexible electronic products. However, integrating the above advantages into one single flexible electronic device is still a huge challenge. Herein, we demonstrate a flexible and recyclable bio-based memory device using fish colloid as the resistive switching layer on a polyimine substrate, which affords reliable mechanical and electrical properties under repetitive conformal deformation operation. This flexible bio-based memory device presents potential analog behaviors including memory characteristics and excitatory current response, which undergoes incremental potentiation in conductance under successive electrical pulses. Moreover, this device is expected to greatly alleviate the environmental problems caused by electronic waste. It can be decomposed rapidly in water and well recycled, which is a promising candidate for transient memories and information security. We believe that this study can provide new possibilities to the field of high-performance transient electronics and flexible resistive memory devices.

Conductive metal and covalent organic frameworks for electrocatalysis: design principles, recent progress and perspective.

Metal and covalent organic frameworks (MOFs/COFs) are emerging promising candidates in the field of catalysts due to their porous nature, chemically well-defined active sites and structural diversity. However, they are typically provided with poor electrical conductivity, which is insufficient for them to work as satisfying electrocatalysts. Designing and fabricating MOFs/COFs with high conductivity presents a new avenue towards special electrochemical reactions. This minireview firstly highlighted the origin and design principles of conductive MOFs/COFs for electrocatalysis on the basis of typical charge transfer mechanisms, that is "through space", "extended conjugation" and "through bond". An overview of conductive MOFs/COFs used in the electrocatalytic carbon dioxide reduction reaction (CO2RR), water splitting and the oxygen reduction reaction (ORR) was then made to track the very recent progress. In the final remarks, the present challenges and perspectives for the use of conductive MOFs/COFs as electrocatalysts including their structural optimization, feasible applications and structure-activity correlation are proposed.