Synchronous Surface-Interface and Crystal-Phase Engineered Multifaceted Hybrid Nanostructure of Fe-(1T)-VSe2 Nanosheet and Fe-CoSe2 Nanorods Doped with P for Rapid HER and OER, Kinetics.

Two different nanostructures of two dissimilar highly-potent active electrocatalysts, P-dopped metallic-(1T)-Fe-VSe2 (P,Fe-1T-VSe2 ) nanosheet and P-dopped Fe-CoSe2 (P,Fe-CoSe2 ) nanorods are hybridized and integrated into a single heterostructure (P,Fe-(VCo)Se2 ) on Ni-foam for high-performance water splitting (WS). The catalytic efficiency of VSe2 nanosheets is first enhanced by enriching metallic (1T)-phase, then forming bimetallic Fe-V selenide, and finally by P-doping. Similarly, the catalytic efficiency of CoSe2 nanorods is boosted by first fabricating Fe-Co bimetallic selenide and then P-doping. To develop super-efficient electrocatalysts for WS, two individual electrocatalysts P,Fe-1T-VSe2 nanosheet and P,Fe-CoSe2 are hybridized and integrated to form a heterostructure (P,Fe-(VCo)Se2 ). Metallic (1T)-phase of transition metal dichalcogenides has much higher conductivity than the 2H-phase, while bimetallization and P-doping activate basal planes, develop various active components, and form heterostructures that develop a synergistic interfacial effect, all of which, significantly boost the catalytic efficacy of the P,Fe-(VCo)Se2 . P,Fe-(VCo)Se2 shows excellent performance requiring very low overpotential (ηHER = 50 mV@10 mAcm-2 and ηOER = 230 mV@20 mAcm-2 ). P,Fe-(VCo)Se2 (+, -) device requires a cell potential of 1.48 V to reach 10 mA cm-2 for overall WS.

Manganese-Doped Bimetallic (Co,Ni)2P Integrated CoP in N,S Co-Doped Carbon: Unveiling a Compatible Hybrid Electrocatalyst for Overall Water Splitting.

Rational design of highly efficient noble-metal-unbound electrodes for hydrogen and oxygen production at increased current density is crucial for robust water-splitting. A facile hydrothermal and room-temperature aging method is presented, followed by chemical vapor deposition (CVD), to create a self-sacrificed hybrid heterostructure electrocatalyst. This hybrid material, (Mn-(Co,Ni)2P/CoP/(N,S)-C), comprises manganese-doped cobalt nickel phosphide (Mn-(Co,Ni)2P) nanofeathers and cobalt phosphide (CoP) nanocubes embedded in a nitrogen and sulfur co-doped carbon matrix (N,S)-C on nickel foam. The catalyst exhibits excellent performance in both the hydrogen evolution reaction (HER; η10 = 61 mV) and oxygen evolution reaction (OER; η10 = 213 mV) due to abundant active sites, high porosity, and enhanced hetero-interface interaction between Mn-(Co2P-Ni2P) CoP, and (N,S)-C supported by significant synergistic effects observed among different phases through density functional theory (DFT) calculations. Impressively, (Mn-(Co,Ni)2P/CoP/(N,S)-C (+,-) shows an extra low cell voltage of 1.49 V@10 mA cm-2. Moreover, the catalyst exhibits remarkable stability at 100 and 300 mA cm-2 when operating as a single stack cell electrolyzer. The superior electrochemical activity is attributed to the enhanced electrode-electrolyte interface among the multiple phases of the hybrid structure.

Bifunctional P-Intercalated and Doped Metallic (1T)-Copper Molybdenum Sulfide Ultrathin 2D-Nanosheets with Enlarged Interlayers for Efficient Overall Water Splitting.

Metallic (1T) molybdenum disulfide (MoS2) is a much better electrocatalyst than the semiconducting (2H) MoS2 because of its superior conductivity, presence of active basal planes, and bulky interlayers. However, the lack of thermodynamic stability has hindered its practical uses. The insertion of transition metals and nonmetals in the interlayers and the crystal is known to improve both the thermodynamic stability and the catalytic efficacy of 1T-MoS2. In this study, for the first time we have developed an electrocatalyst for water splitting based on metallic copper molybdenum sulfide (1T-CMS). The present catalyst, P-doped and intercalated 1T-CMS ultrathin 2D nanosheets on carbon cloth (P-1T-CMS@CC), demonstrates excellent catalytic efficacy for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). It required an overpotential of 95 mV for HER and of 284 mV for OER at a current density of 10 mA cm-2. The P-1T-CMS@CC(+ -) device also shows excellent performance, requiring a cell voltage of only 1.51 V at a current density of 10 mA cm-2.

Alkaline Water Splitting Enhancement by MOF-Derived Fe-Co-Oxide/Co@NC-mNS Heterostructure: Boosting OER and HER through Defect Engineering and In Situ Oxidation.

Introducing defects and in situ topotactic transformation of the electrocatalysts generating heterostructures of mixed-metal oxides(hydroxides) that are highly active for oxygen evolution reaction (OER) in tandem with metals of low hydrogen adsorption barrier for efficient hydrogen evolution reaction (HER) is urgently demanded for boosting the sluggish OER and HER kinetics in alkaline media. Ascertaining that, metal-organic-framework-derived freestanding, defect-rich, and in situ oxidized Fe-Co-O/Co metal@N-doped carbon (Co@NC) mesoporous nanosheet (mNS) heterostructure on Ni foam (Fe-Co-O/Co@NC-mNS/NF) is developed from the in situ oxidation of micropillar-like heterostructured Fe-Co-O/Co@NC/NF precatalyst. The in situ oxidized Fe-Co-O/Co@NC-mNS/NF exhibits excellent bifunctional properties by demanding only low overpotentials of 257 and 112 mV, respectively, for OER and HER at the current density of 10 mA cm-2 , with long-term durability, attributed to the existence of oxygen vacancies, higher specific surface area, increased electrochemical active surface area, and in situ generated new metal (oxyhydr)oxide phases. Further, Fe-Co-O/Co@NC-mNS/NF (+/-) electrolyzer requires only a low cell potential of 1.58 V to derive a current density of 10 mA cm-2 . Thus, the present work opens a new window for boosting the overall alkaline water splitting.

Freestanding 1T-Mnx Mo1- x S2- y Sey and MoFe2 S4- z Sez Ultrathin Nanosheet-Structured Electrodes for Highly Efficient Flexible Solid-State Asymmetric Supercapacitors.

Fabrication of hierarchical nanosheet arrays of 1T phase of transition-metal dichalcogenides is indeed a critical task, but it holds immense potential for energy storage. A single-step strategy is employed for the fabrication of stable 1T-Mnx Mo1- x S2- y Sey and MoFe2 S4- z Sez hierarchical nanosheet arrays on carbon cloth as positive and negative electrodes, respectively. The flexible asymmetric supercapacitor constructed with these two electrodes exhibits an excellent electrochemical performance (energy density of ≈69 Wh kg-1  at a power density of 0.985 kW kg-1 ) with ultralong cyclic stability of ≈83.5% capacity retention, after 10 000 consecutive cycles. Co-doping of the metal and nonmetal boosts the charge storage ability of the transition-metal chalcogenides following enrichment in the metallic 1T phase, improvement in the surface area, and expansion in the interlayer spacing in tandem, which is the key focus of the present study. This study explicitly demonstrates the exponential enhancement of specific capacity of MoS2 following intercalation and doping of Mn and Se, and Fe2 S3 following doping of Mo and Se could be an ideal direction for the fabrication of novel energy-storage materials with high-energy storage ability.

Protein-Nanoparticle Agglomerates as a Plasmonic Magneto-Luminescent Multifunctional Nanocarrier for Imaging and Combination Therapy.

We report the fabrication of a plasmonic magneto-luminescent multifunctional nanocarrier (PML-MF nanocarrier) by lysozyme-mediated agglomeration of gold-coated iron oxide nanoparticles (IO@AuNPs) and subsequent coating of these agglomerates with BSA-stabilized gold nanoclusters (BSA-AuNCs). The agglomeration-mediated enhancement of plasmonic absorbance at the NIR biological window helped in plasmonic photothermal therapy (PPTT) by PML-MF nanocarriers. PML-MF nanocarriers demonstrated excellent in vitro bioimaging and magnetic targeting capabilities due to the strong photoluminance and superparamagnetism of the constituent AuNCs and IO@AuNPs, respectively. Moreover, these nanocarriers showed the successful loading and delivery of doxorubicin to cancer cells with a significant killing efficiency that could be synergistically improved by combining with PPTT.

A White Light-Emitting Quantum Dot Complex for Single Particle Level Interaction with Dopamine Leading to Changes in Color and Blinking Profile.

The interaction of the neurotransmitter dopamine is reported with a single particle white light-emitting (WLE) quantum dot complex (QDC). The QDC is composed of yellow emitting ZnO quantum dots (Qdots) and blue emitting Zn(MSA)2 complex (MSA = N-methylsalicylaldimine) synthesized on their surfaces. Sensing is achieved by the combined changes in the visual luminescence color from white to blue, chromaticity color coordinates from (0.31, 0.33) to (0.24, 0.23) and the ratio of the exponents (αon /αoff ) of on/off probability distribution (from 0.24 to 3.21) in the blinking statistics of WLE QDC. The selectivity of dopamine toward ZnO Qdots, present in WLE QDC, helps detect ≈13 dopamine molecules per Qdot. Additionally, the WLE QDC exhibits high sensitivity, with a limit of detection of 3.3 × 10-9 m (in the linear range of 1-100 × 10-9 m) and high selectivity in presence of interfering biological species. Moreover, the single particle on-off bilking statistics based detection strategy may provide an innovative way for ultrasensitive detection of analytes.

Synergistic Anticancer Potential of Artemisinin When Loaded with 8-Hydroxyquinoline-Surface Complexed-Zinc Ferrite Magnetofluorescent Nanoparticles and Albumin Composite.

Herein, we report the fabrication of a novel class of magnetofluorescent theranostic nanoparticles (MFTNPs) based on "surface-complexation" of zinc ferrite (ZnFe2O4) NPs with 8-hydroxyquinoline. The potential of these MFTNPs in fluorescence-based bioimaging of different cancer cells was successfully demonstrated. The superparamagnetic behavior of the MFTNPs was exploited effectively in magnetic targeting in vitro. Finally, a well-known hydrophobic antimalarial and prospective anticancer drug artemisinin was efficiently loaded into MFTNPs. Artemisinin loaded MFTNPs were observed to induce superior antiproliferative response, as compared to free drug, in cancer cells in a synergistic mechanism with combination index of 0.1 or less.

Protein-Based Multifunctional Nanocarriers for Imaging, Photothermal Therapy, and Anticancer Drug Delivery.

We report a simple approach for fabricating plasmonic and magneto-luminescent multifunctional nanocarriers (MFNCs) by assembling gold nanorods, iron oxide nanoparticles, and gold nanoclusters within BSA nanoparticles. The MFNCs showed self-tracking capability through single- and two-photon imaging, and the potential for magnetic targeting in vitro. Appreciable T2-relaxivity exhibited by the MFNCs indicated favorable conditions for magnetic resonance imaging. In addition to successful plasmonic-photothermal therapy of cancer cells (HeLa) in vitro, the MFNCs demonstrated efficient loading and delivery of doxorubicin to HeLa cells leading to significant cell death. The present MFNCs with their multimodal imaging and therapeutic capabilities could be eminent candidates for cancer theranostics.

Surface Complexation-Based Biocompatible Magnetofluorescent Nanoprobe for Targeted Cellular Imaging.

We report the synthesis of a magnetofluorescent biocompatible nanoprobe-following room temperature complexation reaction between Fe3O4-ZnS nanocomposite and 8-hydroxyquinoline (HQ). The composite nanoprobe exhibited high luminescence quantum yield, low rate of photobleaching, reasonable excited-state lifetime, luminescence stability especially in human blood serum, superparamagnetism and no apparent cytotoxicity. Moreover, the nanoprobe could be used for spatio-controlled cell labeling in the presence of an external magnetic field. The ease of synthesis and cell labeling in vitro make it a suitable candidate for targeted bioimaging applications.

Gold Nanocluster Embedded Albumin Nanoparticles for Two-Photon Imaging of Cancer Cells Accompanying Drug Delivery.

Gold nanoclusters in albumin nanoparticles (nanovehicles) are used for single-photon and two-photon imaging of cancer cells following the delivery of doxorubicin through the nanovehicle. NIR excitation and emission wavelengths in the biological window (650-900 nm) make the nanovehicle an ideal potential platform for imaging guided drug delivery.