Hybrid supercapacitors (battery-supercapacitor hybrid devices, HSCs) deliver high energy within seconds (excellent rate capability) with stable cyclability. One of the key limitations in developing high-performance HSCs is imbalance in power capability between the sluggish Faradaic lithium-intercalation anode and rapid non-Faradaic capacitive cathode. To solve this problem, we synthesize Nb2O5@carbon core-shell nanocyrstals (Nb2O5@C NCs) as high-power anode materials with controlled crystalline phases (orthorhombic (T) and pseudohexagonal (TT)) via a facile one-pot synthesis method based on a water-in-oil microemulsion system. The synthesis of ideal T-Nb2O5 for fast Li(+) diffusion is simply achieved by controlling the microemulsion parameter (e.g., pH control). The T-Nb2O5@C NCs shows a reversible specific capacity of ∼180 mA h g(-1) at 0.05 A g(-1) (1.1-3.0 V vs Li/Li(+)) with rapid rate capability compared to that of TT-Nb2O5@C and carbon shell-free Nb2O5 NCs, mainly due to synergistic effects of (i) the structural merit of T-Nb2O5 and (ii) the conductive carbon shell for high electron mobility. The highest energy (∼63 W h kg(-1)) and power (16 528 W kg(-1) achieved at ∼5 W h kg(-1)) densities within the voltage range of 1.0-3.5 V of the HSC using T-Nb2O5@C anode and MSP-20 cathode are remarkable.

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...

This feature article presents recent progress made in the synthesis of functional ordered mesoporous materials and their application as high performance electrodes in dye-sensitized solar cells (DSCs) and quantum dot-sensitized solar cells (QDSCs), fuel cells, and Li-ion batteries. Ordered mesoporous materials have been mainly synthesized using two representative synthetic methods: the soft template and hard template methods. To overcome the limitations of these two methods, a new method called CASH was suggested. The CASH method combines the advantages of the soft and hard template methods by employing a diblock copolymer, PI-b-PEO, which contains a hydrophilic block and an sp(2)-hybridized-carbon-containing hydrophobic block as a structure-directing agent. After discussing general techniques used in the synthesis of mesoporous materials, this article presents recent applications of mesoporous materials as electrodes in DSCs and QDSCs, fuel cells, and Li-ion batteries. The role of material properties and mesostructures in device performance is discussed in each case. The developed soft and hard template methods, along with the CASH method, allow control of the pore size, wall composition, and pore structure, providing insight into material design and optimization for better electrode performances in these types of energy conversion devices. This paper concludes with an outlook on future research directions to enable breakthroughs and overcome current limitations in this field.

This study describes the one-pot synthesis and single-cell characterization of ordered, large-pore (>30 nm) mesoporous carbon/silica (OMCS) composites with well-dispersed intermetallic PtPb nanoparticles on pore wall surfaces as anode catalysts for direct formic acid fuel cells (DFAFCs). Lab-synthesized amphiphilic diblock copolymers coassemble hydrophobic metal precursors as well as hydrophilic carbon and silica precursors. The final materials have a two-dimensional hexagonal-type structure. Uniform and large pores, in which intermetallic PtPb nanocrystals are significantly smaller than the pore size and highly dispersed, enable pore backfilling with ionomers and formation of the desired triple-phase boundary in single cells. The materials show more than 10 times higher mass activity and significantly lower onset potential for formic acid oxidation as compared with commercial Pt/C, as well as high stability due to better resistivity toward CO poisoning. In single cells, the maximum power density was higher than that of commercial Pt/C, and the stability highly improved, compared with commercial Pd/C. The results suggest that PtPb-based catalysts on large-pore OMCSs may be practically applied as real fuel cell catalysts for DFAFC.

Enzyme-linked immunosorbent assays (ELISAs) have most widely been applied in immunoassays for several decades. However, several unavoidable limitations (e.g., instability caused by structural unfolding) of natural enzymes have hindered their widespread applications. Here, we describe a new nanohybrid consisting of Fe₃O₄ magnetic nanoparticles (MNPs) and platinum nanoparticles (Pt NPs), simultaneously immobilized on the surface of graphene oxide (GO). By synergistically integrating highly catalytically active Pt NPs and MNPs on GO whose frameworks possess high substrate affinity, the nanohybrid is able to achieve up to a 30-fold higher maximal reaction velocity (V(max)) compared to that of free GO for the colorimetric reaction of the peroxidase substrate, 3,3',5,5'-tetramethylbenzidine (TMB), and enable rapid detection of target cancer cells. Specifically, using this new assay system, clinically important breast cancer cells are detected in a 5 min time period at room temperature with high specificity and sensitivity. The remarkably high capability to catalyze oxidation reactions could allow the nanohybrid to replace conventional peroxidase-based immunoassay systems as part of new, rapid, robust and convenient assay systems which can be widely utilized for the identification of important target molecules.