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While inheriting the exceptional merits of single atom catalysts, diatomic site catalysts (DASCs) utilize two adjacent atomic metal species for their complementary functionalities and synergistic actions. Herein, a DASC consisting of nickel-iron hetero-diatomic pairs anchored on nitrogen-doped graphene is synthesized. It exhibits extraordinary electrocatalytic activities and stability for both CO 2 reduction reaction (CO 2 RR) and oxygen evolution reaction (OER). Furthermore, the rechargeable Zn-CO 2 battery equipped with such bifunctional catalyst shows high Faradaic efficiency and outstanding rechargeability. The in-depth experimental and theoretical analyses reveal the orbital coupling between the catalytic iron center and the adjacent nickel atom, which leads to alteration in orbital energy level, unique electronic states, higher oxidation state of iron, and weakened binding strength to the reaction intermediates, thus boosted CO 2 RR and OER performance. This work provides critical insights to rational design, working mechanism, and application of hetero-DASCs. Diatomic site catalysts utilize two adjacent atomic metal species for their complementary functionalities and synergistic actions. Here, the authors report the orbital coupling of hetero-diatomic nickel-iron site boosts CO 2 reduction reaction and oxygen evolution reaction.

The universal linear scaling relationships between the adsorption energies of reactive intermediates limit the performance of catalysts in multi-step catalytic reactions. Here, we show how these scaling relationships can be circumvented in electrochemical oxygen evolution reaction by dynamic structural regulation of active sites. We construct a model Ni-Fe 2 molecular catalyst via in situ electrochemical activation, which is able to deliver a notable intrinsic oxygen evolution reaction activity. Theoretical calculations and electrokinetic studies reveal that the dynamic evolution of Ni-adsorbate coordination driven by intramolecular proton transfer can effectively alter the electronic structure of the adjacent Fe active centre during the catalytic cycle. This dynamic dual-site cooperation simultaneously lowers the free energy change associated with O–H bond cleavage and O–O bond formation, thereby disrupting the inherent scaling relationship in oxygen evolution reaction. The present study not only advances the development of molecular water oxidation catalysts, but also provides an unconventional paradigm for breaking the linear scaling relationships in multi-intermediates involved catalysis. Circumventing linear scaling relationships in multi-step catalytic reactions is meaningful but challenging. Here, the authors report a method to break this scaling relationship in the oxygen evolution reaction through dynamic regulation of the active site in a Ni-Fe molecular complex catalyst.

Developing non‐precious‐metal electrocatalysts that can operate with a low overpotential at a high current density for industrial application is challenging. Heterogeneous bimetallic phosphides have attracted much interest. Despite high hydrogen evolution reaction (HER) performance, the ordinary oxygen evolution reaction (OER) performance hinders their practical use. Herein, it is shown that Fe‐doping reverses and enlarges the interfacial electrical field at the heterojunction, turning the H intermediate favorable binding sites for HER into O intermediate favorable sites for OER. Specifically, the self‐supported heterojunction catalysts on nickel foam (CoP@Ni2P/NF and Fe‐CoP@Fe‐Ni2P/NF) are readily synthesized. They only require the overpotentials of 266 and 274 mV to drive a large current density of 1000 mA cm−2 (j1000) for HER and OER, respectively. Furthermore, a water splitting cell equipped with these electrodes only requires a voltage of 1.724 V to drive j1000 with excellent durability, demonstrating the potential of industrial application. This work offers new insights on interfacial engineering for heterojunction catalysts. A new interfacial engineering strategy is utilized to modulate the catalytic properties of self‐supported heterojunction catalysts by Fe doping. It can reverse and enlarge the interfacial electric field, thereby converting the HER‐active sites in CoP@Ni2P/NF to OER‐active stie in Fe‐CoP@Fe‐Ni2P/NF. The overall water splitting cell equipped with the two electrodes only required a low voltage of 1.724 V to drive the j1000 with long‐term stability.

Double-shelled hollow carbon spheres with reduced graphene oxide (RGO) as inner shell and carbon (C) layer as outer shell have been successfully designed and prepared. This tailor-making structure acts as an excellent capsule for encapsulating with ultrafine Pd nanoparticles (Pd NPs), which could effectively prevent Pd NPs from aggregation and leaching. As a result, the as-obtained RGO@Pd@C nanohybid exhibits superior and stable catalytic performance. With the aid of RGO@Pd@C, the reduction reaction of 4-nitrophenol (4-NP) to 4-aminophenol with NaBH 4 as reducing agent can be finished within only 30 s, even the content of Pd is as low as 0.28 wt%. As far as we know, RGO@Pd@C is one of the most effective catalyst for 4-NP reducing reaction up to now.

RationaleTo realize imaging-guided multi-modality cancer therapy with minimal side effects remains highly challenging.MethodsWe devised a bioinspired hollow nitrogen-doped carbon sphere anchored with individually dispersed Mn atoms (Mn/N-HCN) via oxidation polymerization with triton micelle as a soft template, followed by carbonization and annealing. Enzyme kinetic analysis and optical properties were performed to evaluate the imaging-guided photothermally synergized nanocatalytic therapy.ResultsSimultaneously mimicking several natural enzymes, namely peroxidase (POD), catalase (CAT), oxidase (OXD), and glutathione peroxidase (GPx), this nano-multizyme is able to produce highly cytotoxic hydroxyl radical (•OH) and singlet oxygen (1O2) without external energy input through parallel and series catalytic reactions and suppress the upregulated antioxidant (glutathione) in tumor. Furthermore, NIR-II absorbing Mn/N-HCN permits photothermal therapy (PTT), enhancement of CAT activity, and photoacoustic (PA) imaging to monitor the accumulation kinetics of the nanozyme and catalytic process in situ. Both in vitro and in vivo experiments demonstrate that near-infrared-II (NIR-II) PA-imaging guided, photothermally enhanced and synergized nanocatalytic therapy is efficient to induce apoptosis of cancerous cells and eradicate tumor tissue.ConclusionsThis study not only demonstrates a new method for effective cancer diagnosis and therapy but also provides new insights into designing multi-functional nanozymes.

We report a facile and green method to synthesize a new type of catalyst by coating Pd nanoparticles (NPs) on reduced graphene oxide (rGO)-carbon nanotube (CNT) nanocomposite. An rGO–CNT nanocomposite with three-dimensional microstructures was obtained by hydrothermal treatment of an aqueous dispersion of graphene oxide (GO) and CNTs. After the rGO–CNT composites have been dipped in K 2 PdCl 4 solution, the spontaneous redox reaction between the GO–CNT and PdCl 4 2− led to the formation of nanohybrid materials consisting rGO–CNT decorated with 4 nm Pd NPs, which exhibited excellent and stable catalytic activity: the reduction of 4-nitrophenol to 4-aminophenol using NaBH 4 as a catalyst was completed in only 20 s at room temperature, even when the Pd content of the catalyst was 1.12 wt%. This method does not require rigorous conditions or toxic agents and thus is a rapid, efficient and green approach to the fabrication of highly active catalysts.

We reported a scalable and modular method to prepare a new type of sandwich-structured graphene-based nanohybrid paper and explore its practical application as high-performance electrode in flexible supercapacitor. The freestanding and flexible graphene paper was firstly fabricated by highly reproducible printing technique and bubbling delamination method, by which the area and thickness of the graphene paper can be freely adjusted in a wide range. The as-prepared graphene paper possesses a collection of unique properties of highly electrical conductivity (340 S cm −1 ), light weight (1 mg cm −2 ) and excellent mechanical properties. In order to improve its supercapacitive properties, we have prepared a unique sandwich-structured graphene/polyaniline/graphene paper by in situ electropolymerization of porous polyaniline nanomaterials on graphene paper, followed by wrapping an ultrathin graphene layer on its surface. This unique design strategy not only circumvents the low energy storage capacity resulting from the double-layer capacitor of graphene paper, but also enhances the rate performance and cycling stability of porous polyaniline. The as-obtained all-solid-state symmetric supercapacitor exhibits high energy density, high power density, excellent cycling stability and exceptional mechanical flexibility, demonstrative of its extensive potential applications for flexible energy-related devices and wearable electronics.

Current anti-obesity medications suffer from limited efficacy and side-effects because they act indirectly on either the central nervous system or gastrointestinal system. Herein, this work aims to introduce a transdermal photothermal and nanocatalytic therapy enabled by Prussian blue nanoparticles, which directly act on obese subcutaneous white adipose tissue (sWAT) to induce its beneficial remodeling including stimulation of browning, lipolysis, secretion of adiponectin, as well as reduction of oxidative stress, hypoxia, and inflammation. Prussian blue nanoparticles were synthesized and incorporated into silk fibroin hydrogel for sustained retention. The efficacy of mild photothermal (808 nm, 0.4 W/cm , 5 min) and nanocatalytic therapy (mPTT-NCT) was assessed both (3T3-L1 adipocytes) and (obese mice). The underlying signaling pathways are carefully revealed. Additionally, biosafety studies were conducted to further validate the potential of this therapy for practical application. On 3T3-L1 adipocytes, mPTT-NCT was able to induce browning, enhance lipolysis, and alleviate oxidative stress. On obese mice model, the synergistic treatment led to not only large mass reduction of the targeted sWAT (53.95%) but also significant improvement of whole-body metabolism as evidenced by the substantial decrease of visceral fat (65.37%), body weight (9.78%), hyperlipidemia, and systemic inflammation, as well as total relief of type 2 diabetes. By directly targeting obese sWAT to induce its beneficial remodeling, this synergistic therapy leads to significant improvements in whole-body metabolism and the alleviation of obesity-related conditions, including type 2 diabetes. The elucidation of underlying signaling pathways provides fundamental insights and shall inspire new strategies to combat obesity and its associated diseases.

Recent advances in flexible fiber-based microelectrodes have opened a new horizon for sensitive real-time near-cell and even intracellular measurements. In this work, we develop a new type of hierarchical nanohybrid microelectrode based on three-dimensional (3D) porous graphene-wrapped activated carbon fiber (ACF) via a facile and effective electrodeposition of graphene oxide (GO) nanosheets on ACF using a green ionic liquid (IL) as the electrolyte. This technique enables the simultaneous electrodeposition and electrochemical reduction of GO nanosheets on ACF to form 3D porous IL functionalized electrochemically reduced GO (ERGO)-wrapped ACF (IL–ERGO/ACF). The adsorbed IL molecules on the ERGO surface provide sufficient active sites and act as the template for the in situ electrodeposition of highly dense and well-dispersed bimetal PtAu nanoflowers on the 3D IL–ERGO scaffold. By virtue of the unique array of structural and chemical properties of bimetal PtAu nanocatalysts and 3D porous IL–ERGO on ACF, the resultant PtAu nanoflowers-decorated IL–ERGO/ACF (PtAu/IL–ERGO/ACF) microelectrode demonstrates a variety of excellent sensing performances, including high sensitivity, a wide linear range and good selectivity in the electrochemical detection of a newly emerged cancer biomarker, hydrogen peroxide (H 2 O 2 ). When used for the real-time tracking of H 2 O 2 secreted from female cancer cells, such as breast cancer cells and gynecological cancer cells, the electrochemical sensor based on the PtAu/IL–ERGO/ACF microelectrode provides important information for distinguishing between different cancer cells and normal cells and for evaluating the therapeutic activity of antitumor drugs towards live cancer cells, which are of great clinical significance for cancer diagnosis and management. Carbon fibre sensors: sniffing out cancer with nanoflowers Super-tough fibres, thinner than human hair, can sense the biomarkers emitted by cancer cells thanks to a nanostructured coating. Carbon-fibre microelectrodes offer the ability to measure tiny amounts of bodily fluids non-invasively. Fei Xiao from Huazhong University of Science and Technology in China and co-workers now report a way to tune the sensitivity of fibre sensors to hydrogen peroxide — a small-molecule metabolite commonly emitted by breast cancers. Three-dimensional, micron-thick graphene coatings, achieved by immersing acid-activated carbon fibres and nanosheet precursors in an ionic liquid, enabled the team to boost electrode sensitivity to levels needed for in vitro studies. The ionic liquids also helped attach platinum–gold catalysts with unique ‘nanoflower’ shapes to the graphene wrapping. The catalyst-enhanced microelectrode proved accurate at distinguishing different lines of cancer cells and evaluating antitumour medications. We develop a new type of flexible nanohybrid microelectrode by decorating high dense PtAu alloy nanoflowers on 3D porous ionic liquid functionalized graphene wrapped activated carbon fiber. In virtue of the unique array of structural and chemical properties, the resultant hierarchical nanohybrid microelectrode exhibits a collection of good sensing performances, and can be used in near-cell sensitive detection of cancer biomarker secreted from different female cancer cells in normal state and treated by antitumor drug, which provides important information in distinguishing different cancer cells and normal cells and evaluating the therapeutic activity of antitumor drug towards the live cancer cells.

While inheriting the exceptional merits of single atom catalysts, diatomic site catalysts (DASCs) utilize two adjacent atomic metal species for their complementary functionalities and synergistic actions. Herein, a DASC consisting of nickel-iron hetero-diatomic pairs anchored on nitrogen-doped graphene is synthesized. It exhibits extraordinary electrocatalytic activities and stability for both CO reduction reaction (CO RR) and oxygen evolution reaction (OER). Furthermore, the rechargeable Zn-CO battery equipped with such bifunctional catalyst shows high Faradaic efficiency and outstanding rechargeability. The in-depth experimental and theoretical analyses reveal the orbital coupling between the catalytic iron center and the adjacent nickel atom, which leads to alteration in orbital energy level, unique electronic states, higher oxidation state of iron, and weakened binding strength to the reaction intermediates, thus boosted CO RR and OER performance. This work provides critical insights to rational design, working mechanism, and application of hetero-DASCs.