Nanomaterials-based biomimetic catalysts with multiple functions are necessary to address challenges in artificial enzymes mimicking physiological processes. Here we report a metal-free nanozyme of modified graphitic carbon nitride and demonstrate its bifunctional enzyme-mimicking roles. With oxidase mimicking, hydrogen peroxide is generated from the coupled photocatalysis of glucose oxidation and dioxygen reduction under visible-light irradiation with a near 100% apparent quantum efficiency. Then, the in situ generated hydrogen peroxide serves for the subsequent peroxidase-mimicking reaction that oxidises a chromogenic substrate on the same catalysts in dark to complete the bifunctional oxidase-peroxidase for biomimetic detection of glucose. The bifunctional cascade catalysis is successfully demonstrated in microfluidics for the real-time colorimetric detection of glucose with a low detection limit of 0.8 μM within 30 s. The artificial nanozymes with physiological functions provide the feasible strategies for mimicking the natural enzymes and realizing the biomedical diagnostics with a smart and miniature device.

Single-atom catalysts (SACs) have attracted growing attention because they maximizet he number of active sites, with unpredictable catalytic activity.Despite numerous studies on SACs,t here is little researcho nt he support, which is essential to understanding SAC. Herein, we systematically investigated the influence of the support on the performance of the SACb yc omparing with single-atom Pt supported on carbon (Pt SA/C) and Pt nanoparticles supported on WO 3Àx (Pt NP/WO 3Àx ). The results revealed that the support effect was maximized for atomically dispersed Pt supported on WO 3Àx (Pt SA/WO 3Àx ). The Pt SA/WO 3Àx exhibited ahigher degree of hydrogen spillover from Pt atoms to WO 3Àx at the interface, compared with Pt NP/WO 3Àx ,w hichd rastically enhanced Pt mass activity for hydrogen evolution (up to 10 times). This strategy provides an ew framework for enhancing catalytic activity for HER, by reducing noble metal usage in the field of SACs.Hydrogen is being pursued as af uture alternative to fossil fuels and an ideal energy carrier for renewable energy, because it has the highest energy density per mass without any pollutants.Currently,hydrogen production is primarily based on the steam reforming of fossil fuels,w hich is accompanied by environmental issues,s uch as as ubstantial increase in atmospheric CO 2 .Accordingly,itisnecessary to find sustainable and clean alternatives. [1] Electrochemical water splitting is considered ap otentially cost-effective and promising approach for clean hydrogen production. [2] Fort he cathodic hydrogen evolution reaction (HER), platinum (Pt)-based materials are known to the most active electrocatalysts,b ut the high cost and scarcity of Pt are key obstacles to commercial applications of water electrolyzers. [3] Hitherto,n umerous design strategies have been developed for nanostructured electrocatalysts to obtain outstanding electrochemical performance. [4] These strategies are shown to improve the utilization of Pt, and thereby to reduce the use of Pt. Fore xamples,c ore-shell [5] and hollow structures [6] can significantly improve Pt utilization by diminishing the buried non-active Pt atoms inside the particles. From this point of view,single-atom catalysts (SACs), where all metal species are individually dispersed on ad esired support, could be the best candidates to meet this goal, because they offer the maximum number of surface exposed Pt atoms.S everal studies have also demonstrated that Pt SACs show greatly boosted Pt mass activity compared to commercial Pt/C.However,research that considers the effect of the support on SACs performance for the HER is rarely found. [3,7] Thec hoice of support material is one of the most promising strategies for improving (electro)catalysis because interactions between the metal and support can drastically tune the electronic structure of the supported metal, and enhance performance. [8] Furthermore,i th as been recently reported that HER performance can be improved by not only changing the electronic structure of the supported m...

Synaptic adhesion molecules orchestrate synaptogenesis. The presynaptic leukocyte common antigen-related receptor protein tyrosine phosphatases (LAR-RPTPs) regulate synapse development by interacting with postsynaptic Slit-and Trk-like family proteins (Slitrks), which harbour two extracellular leucine-rich repeats (LRR1 and LRR2). Here we identify the minimal regions of the LAR-RPTPs and Slitrks, LAR-RPTPs Ig1-3 and Slitrks LRR1, for their interaction and synaptogenic function. Subsequent crystallographic and structureguided functional analyses reveal that the splicing inserts in LAR-RPTPs are key molecular determinants for Slitrk binding and synapse formation. Moreover, structural comparison of the two Slitrk1 LRRs reveal that unique properties on the concave surface of Slitrk1 LRR1 render its specific binding to LAR-RPTPs. Finally, we demonstrate that lateral interactions between adjacent trans-synaptic LAR-RPTPs/Slitrks complexes observed in crystal lattices are critical for Slitrk1-induced lateral assembly and synaptogenic activity. Thus, we propose a model in which Slitrks mediate synaptogenic functions through direct binding to LAR-RPTPs and the subsequent lateral assembly of LAR-RPTPs/Slitrks complexes.

We use a combination of density functional theory (DFT) calculations and experimental approaches to explore the stability and electrocatalytic activity of a wide range of transitionmetal single atoms on a TiC support. Our theoretical prediction that single atoms can be stabilized on the modified TiC surface is confirmed by experimental findings using them on a TiC support. The predicted activities where Pt and Au single atoms would be the best for hydrogen evolution and selective oxygen reduction reactions, respectively, agree well with experimental results. This rational strategy using computational modeling of materials enables effective design of highly active and stable single-atom catalysts.

Lithium-sulfur (Li-S) batteries are regarded as potential high-energy storage devices due to their outstanding energy density. However, the low electrical conductivity of sulfur, dissolution of the active material, and sluggish reaction kinetics cause poor cycle stability and rate performance. A variety of approaches have been attempted to resolve the above issues and achieve enhanced electrochemical performance. However, inexpensive multifunctional host materials which can accommodate large quantities of sulfur and exhibit high electrode density are not widely available, which hinders the commercialization of Li-S batteries. Herein, mesoporous carbon microspheres with ultrahigh pore volume are synthesized, followed by the incorporation of Fe-N-C molecular catalysts into the mesopores, which can act as sulfur hosts. The ultrahigh pore volume of the prepared host material can accommodate up to ∼87 wt % sulfur, while the uniformly controlled spherical morphology and particle size of the carbon microspheres enable high areal/volumetric capacity with high electrode density. Furthermore, the uniform distribution of Fe-N-C (only 0.33 wt %) enhances the redox kinetics of the conversion reaction of sulfur and efficiently captures the soluble intermediates. The resulting electrode with 5.2 mg sulfur per cm shows excellent cycle stability and 84% retention of the initial capacity even after 500 cycles at a 3 C rate.

To promote the oxygen reduction reaction of metal-free catalysts, the introduction of porous structure is considered as a desirable approach because the structure can enhance mass transport and host many catalytic active sites. However, most of the previous studies reported only half-cell characterization; therefore, studies on membrane electrode assembly (MEA) are still insufficient. Furthermore, the effect of doping-site position in the structure has not been investigated. Here, we report the synthesis of highly active metal-free catalysts in MEAs by controlling pore size and doping-site position. Both influence the accessibility of reactants to doping sites, which affects utilization of doping sites and mass-transport properties. Finally, an N,P-codoped ordered mesoporous carbon with a large pore size and precisely controlled doping-site position showed a remarkable on-set potential and produced 70% of the maximum power density obtained using Pt/C.

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Copper phosphide (Cu x P) was synthesized and tested for its reactivity for generating H2O2 through spontaneous reduction of dioxygen under ambient aqueous condition. The in situ generated H2O2 was subsequently decomposed to generate OH radicals, which enabled the degradation of organic compounds in water. The oxygen reduction reaction proceeded along with the concurrent oxidation of phosphide to phosphate, then copper ions and phosphate ions were dissolved out during the reaction. The reactivity of Cu x P was gradually reduced during 10 cycles with consuming 8.7 mg of Cu x P for the successive removal of 17 μmol 4-chlorophenol. CoP which was compared as a control sample under the same experimental condition also produced H2O2 through activating dioxygen but did not degrade organic compounds at all. The electrochemical analysis for the electron transfers on Cu x P and CoP showed that the number of electrons transferred to O2 is 3 and 2, respectively, which explains why OH radical is generated on Cu x P, not on CoP. The Cu+ species generated on the Cu x P surface can participate in Fenton-like reaction with in situ generated H2O2. Cu x P is proposed as a solid reagent that can activate dioxygen to generate reactive oxygen species in ambient aqueous condition, which is more facile to handle and store than liquid/gas reagents (e.g., H2O2, Cl2, O3).