The global quest for a sustainable energy matrix is fundamentally a crisis of material constraints where success relies on structural control at the atomic scale. Herein, we report a universal, physical protocol: cyclic rapid annealing and cooling (CRAC) that simultaneously orchestrates phase-engineering and dimensional reduction. By subjecting bulk TMDs (MoS2, MoSe2, and CoSe2) to extreme, repetitive cryo-thermal shocks, we induce a controlled structural fracturing that yields zero-dimensional (0D) nanoparticles with locked metastable phases (1T/cubic) through rapid kinetic quenching. Comprehensive characterization reveals a profound alteration of the materials' physical landscape: X-ray diffraction and spectroscopic analyses confirm a dominant metallic phase concentration, while electron microscopy unveils sub-10 nm nanoclusters with an abundance of exposed edge sites. Consequently, these CRAC-engineered 0D TMDs exhibit exceptional electrocatalytic performance, delivering very low overpotentials and robust kinetics for the hydrogen and oxygen evolution reactions (HER/OER), high-efficiency oxygen reduction reaction (ORR) pathways, and superior rate capability in super capacitive energy storage. This electrocatalytic prowess originates from the dual-modulation technique. By bridging the gap between materials engineering and electrochemistry, this work provides a universal and scalable blueprint for sculpting earth-abundant materials into high-performance catalysts, establishing a new frontier in the design of noble-metal-free energy technologies.

The production of electrocatalytically active materials from inert precursors through intricate engineering represents a frontier in sustainable energy research. The present study unveils a transformative thermal stress-mediated fracturing strategy to activate the oxygen reduction reaction (ORR) in SnS2, a material traditionally considered unsuitable for such electrocatalytic applications. By subjecting bulk SnS2 hexagonal plates to extreme thermal shock via rapid heating followed by instant quenching in liquid nitrogen, a simultaneous reduction in dimensionality and a critical 1T-to-1H phase transition has been achieved, yielding ultra-small 1H@1T-SnS2 nanodots (2-5 nm). High-resolution aberration-corrected STEM imaging reveals a restructured atomic lattice where the emergence of the 1H phase, coupled with plentiful edge sites, fundamentally reconfigures the electronic landscape. While the parent 1T-SnS2 follows an inefficient 2-electron pathway, the phase-restructured nanodots exhibit a robust 4-electron oxygen reduction mechanism. Theoretical insights from Density Functional Theory (DFT) confirm that the synergy between the 1H-phase transition and edge-site enrichment lowers the Gibbs free energy for intermediate adsorption, effectively "unlocking" the catalytic potential of SnS2. This work provides an erudite blueprint for the phase-and-size engineering of non-precious metal dichalcogenides, transmuting mundane semiconductors into high-performance electrocatalysts for the next generation of fuel cells and metal-air batteries.

Recently electrochemical urea oxidation reaction (UOR) has emerged as the technology of demand for commercialization of urea-based energy conversion. However, the nascent idea is limited by the energy burden of threshold voltage and the sluggish reaction kinetics involving a six-electron transfer mechanism. Herein, for the first time, the engineering of electrocatalysts are proposed with simultaneous inclusion of UOR activator and UOR accelerator. Nitrogen-doped carbon-decorated Ni-based Metal Organic Framework (MOF) has been synthesized as the base catalyst material. MoO2 and rGO with varied loading have been attached to the MOF to get the desired MoO2/Ni-MOF/rGO heterostructure incorporating defects and crystal strain within the materials. Investigations reveal that the invoked lattice strain and atomic defects promote plenteous Ni3+ active sites. The optimized sample demonstrates extraordinary performance of UOR having the potential value as low as 1.32 V versus RHE to reach the current density of 10 mA cm(-2) and the tafel slope is only 31 mV dec(-1) reflecting very fast reaction kinetics. Here MoO2 plays the role of UOR activator whereas optimized loading of rGO proliferates the reaction speed. This work, experimentally and theoretically, presents a new insight to enhance electrocatalytic urea oxidation reaction opening an avenue of urea-based energy-harvesting technology.

Meticulous tuning of nonprecious catalysts for overall water splitting is highly challenging but it is one of the most promising routes toward the future hydrogen economy. Here, we present a highly active, robust and earth abundant NiCoP electrocatalyst with a tuning capacity to excel in both oxygen and hydrogen evolution reactions. The composition of Ni and Co has been varied in a facile two-step method to produce coral-like NiCoP. The variant Ni0.25Co0.75 P has shown remarkable OER activity with overpotential as low as 240 mV at 10 mA cm-2 current density and Tafel slope of 68 mVdec-1 in alkaline medium. On the other hand, Ni0.75Co0.25P exhibited commendable HER performance with an overpotential of 120 mV and a Tafel slope of 123 mVdec-1 in an acid medium. Long-term durability and minimal loading of the catalyst ascertain the significance of the present catalyst. Moreover, our theoretical study finds that NiCoP provides a much higher electron density of d-states near the Fermi level compared to the individual metal phosphide and the low-index surface (100) of composite phosphide has a moderate level of desorption energy of oxygen and hydrogen compared to that of NiP2 & CoP corroborating the superiority of NiCoP in OER/HER performance.

The most vital issues of the modern world for a sustainable future are "health" and "the environment." Scientific endeavors to tackle these two major concerns for mankind need serious attention. The photocatalytic activity toward curbing environmental pollution and antibacterial performance toward a healthy society are two directions that have been emphasized for decades. Recently, materials engineering, in their nanodimension, has shown tremendous possibilities to integrate these functionalities within the same materials. In particular, hybrid nanostructures have shown magnificent prospects to combat both crucial challenges. Many researchers are separately engaged in this important field of research but the collective knowledge on this domain which can facilitate them to excel is badly missing. The present article integrates the development of different hybrid nanostructures which exhibit both photocatalytic degradations of environmental pollutants and antibacterial efficiency. Various synthesis techniques of those hybrid nanomaterials have been discussed. Hybrid nanosystems based on several successful materials have been categorically discussed for better insight into the research advancement in this direction. In particular, Ag-based, metal oxides-based, layered carbon material-based, and Mexene- and self-cleaning-based materials have been chosen for detailing their performance as anti-pollutant and antibacterial materials. Those hybrid systems along with some miscellaneous booming nanostructured materials have been discussed comprehensively with their success and limitations toward their bifunctionality as antipollutant and antibacterial agents.

The development of low-cost and high-efficient electrocatalysts with multifunctionality by nanocomposite formation is an emerging route for addressing sustainable energy issues. This study reports the nanocomposite of alpha-Fe2O3 nanoparticles embedded in g-C(3)N(4)nanosheets synthesized by a facile chemical route. The synthesized nanocomposite was examined for structural, chemical, and morphological details. The optical study of the sample exhibits the potential capability of photon capture and electron-hole separation towards photo-excited applications. Magnetic study of the alpha-Fe2O3/g-C3N4 nanocomposite reveals that composite formation does not possess characteristic blocking temperature as present in bare alpha-Fe2O3 nanoparticles at 62 K accompanying enhancement of remanent magnetization and coercivity at 5 K.The prepared nanocomposite was tested for oxygen reduction reaction (ORR) in an alkaline medium and it exhibited appreciable catalytic performance with considerable methanol tolerance and excellent durability. It also reveals that the composite catalyzes ORR by two steps: first by two-electron transfer and then immediately by 4-electron direct pathway resulting in complete reduction of oxygen to water.

In the past decade, the surge in research of layered metal dichalcogenides (LMDs) has already demonstrated the tremendous potentiality of this particular category of materials towards technology. But in parallel, it is also established that to make them technology-perfect meticulous engineering to impose ‘imperfections’ within the materials is inevitable. So exploring different LMD with inexorable and appropriate engineering techniques for the enhancement of their functionality is the burning issue for materials scientists. This review comprehensively focuses on different pathways of introducing ‘imperfections’ within various LMDs, mainly by engineering the thickness, morphology, defect, doping and phase. Based on recent progress thickness and shape engineering of LMDs have been discussed with their success and modulation by defect has been examined in detail. Doping and phase engineering of LMDs have also been illustrated with the light of development till now. Finally, challenges and opportunities associated with this research direction are highlighted.

Search for cost effective, earth abundant electrocatalysts for hydrogen generation through water splitting is the challenge of the hour whereas multifunctional applicability of the materials is the extremely sought issue for multi-tasking smart materials. In this work, nitrogen doped reduced graphene oxide (N-rGO) supported nickel phosphide (NixPy) nanomaterial has been prepared and characterized. Details electrocatalytic measurements exhibit the commendable performance of the composite materials against hydrogen evolution reaction in acid medium. The reduction of the required overpotential for reaching 10 mA/cm2 from 265 mV (NixPy) to 248 mV (NixPy/N-rGO) is observed in 0.5 M H2SO4 solution which proves the benefit for attaching N-rGO with NixPy. The electrochemical active surface area measurement also ascertains the quality of the composite and the enhancement of an active surface area is attributed to the attachment of N-rGO matrix. Furthermore, the NixPy/N-rGO composite confirms it’s stability in the acidic medium for 1200 min at 248 mV without any significant loss of current. Ground state ferromagnetic behavior has been demonstrated by NixPy/N-rGO in sharp contrast to the paramagnetic behavior exhibited by the bare NixPy nanoclusters at low temperature. Thus, the N-rGO matrix supported NixPy manifests both electrocatalytic proficiency and magnetic ordering with potential application in the future green energy as well as in data storage technologies.

Here we present direct exfoliation of ultrathin silicon nanosheets from commercial silicon powders through an improved liquid phase exfoliation procedure. The feasibility of exfoliation was ascribed to the intrinsic anisotropic lattice structure, which allowed the oriented propagations of cryo-mediation-induced quenching cracks with the assistance of sonication. It was also revealed that the solid-solvent interface played a critical role in determining the morphology of exfoliated pieces as well as the exfoliation efficiency. Moreover, due to its superior morphology, enlarged surface area, and improved photon absorption, the resulting ultrathin silicon nanosheets presented enhanced and visible light responsive photocatalytic hydrogen generation performance, even without applying any co-catalyst.

The need to develop non precious electrocatalysts for effective hydrogen evolution reaction, towards clean and sustainable energy resources has emerged as the prime issue from the perspective of material scientists. Here in this work, we show that synergistic effect of chemical co-doping with nitrogen and phosphorus activates the inert basal planes and aids in faster electron transfer to achieve extraordinarily enhanced hydrogen evolution reaction in acidic medium. The synthesized N,P-dual doped Molybdenum disulfide nanosheets exhibited excellent electrocatalytic activity for HER with a Tafel slope of 92 mVdec(-1) and a low overpotential of 0.295 V (vs RHE without iR compensation) at 10 mAcm(-2).. The synthesized samples exhibited satisfactory stability in the acidic medium with just 0.016 mV loss of the onset potential at the current density 60 mAcm(-2).

The engineering of pristine low dimensional materials towards society-needed functionalities is the driving force for cultivation the field of nano–bio research.

Due to the accelerating growth of civilian and industrial regime, chemical and bioremediation of water body become a major concern for society. Here, we report a facile and scalable process to get Zinc-aluminium layered double hydroxide (LDH) with carbonate interlayer anion and present it as promising multifunctional material for potential applications in adsorption, antibacterial, and cytotoxicity performances. In this study, the sample was prepared by co-precipitation method and the well crystalline LDH was characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscope (TEM), X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) analysis. The study shows excellent adsorption capacity of Zn2Al-CO3 LDH as high as 81.4 mg/g against the methyl orange (MO) dye taken as a model organic pollutant. Adsorption kinetics and adsorption isotherms have also been investigated in detail. Moreover, the prepared Zn2Al-CO3 LDH sample shows commendable antimicrobial efficacy against both Gram-negative and Gram-positive bacteria. In addition to that, under cytotoxicity study, the sample exhibits a creditable inhibitory effect towards the cancerous cell HEPG2 cell. As a whole the results show the significant implication of the Zn2Al-CO3 LDHas a multifunctional material towards environmental concern and also as an antimicrobial material.

Accelerating thrust has been noticed for the last couple of years in the direction of new two dimensional materials for fruitful functional applications. Zn/Al layered double hydroxide (LDH) with intercalated anion carbonate as visible light response photo catalyst was fabricated by co-precipitation method. The as prepared LDH photo catalyst was characterized to reveal the structure and texture. The photo catalysis activity of the 2D materials was studied by degradation of an anionic dye methyl orange and a cationic dye methylene blue. It is found that Zn/Al-CO3 LDH has magnificent performance for the degradation of anionic dye and the efficiency is superior to the performance on cationic dye. The kinetics and mechanism of photo catalytic dye degradation of Zn/Al-CO3 LDH were also discussed. The work presents layered materials by facile synthesis and open up the opportunity for easy and cost effective water remediation.

Identifying atomic/molecular mechanism is crucial for understanding crystallization and epitaxial growth and to enable controlled synthesis of high-quality devices and desired crystalline structures. Using scanning tunneling microscopy, we studied early stages of Si epitaxy on a Si(1 1 1) surface mediated by a Pb monolayer. A type of highly mobile magic clusters was observed only when they were trapped at boundary or defect sites. Magic clusters also formed cluster aggregates temporarily. Adding more Si transformed the aggregates into immobile metastable or stable structures. Here we propose a scenario involving concerted chemical reactions of multiple, co-localized magic clusters with the activation energies decreasing with increasing number of clusters. This scenario may be modified to understand nucleation and growth of many covalent materials as well as crystallization in numerous synthetic and natural systems.

Meticulous surface engineering of layered structures toward new functionalities is a demanding challenge to the scientific community. Here, we introduce defects on varied MoS2 surfaces by suitable doping of nitrogen atoms in a sulfur-rich reaction environment, resulting in stable and scalable phase conversion. The experimental characterizations along with the theoretical calculations within the framework of density functional theory establish the impact of nitrogen doping on stabilization of defects and reconstruction of the 2H to 1T phase. The as-synthesized MoS2 samples exhibit excellent dye removal capacity in the dark, facilitated by a synergistic effect of reactive oxygen species (ROS) generation and adsorption. Positron annihilation spectroscopy and electron paramagnetic resonance studies substantiate the role of defects and associated sulfur vacancies toward ROS generation in the dark. Further, on the basis of its ample ROS generation in the dark and in the light, the commendable antimicrobial activity of the prepared MoS2 samples against fungal pathogen Alternaria alternata has been demonstrated. Thus, the present study opens up a futuristic avenue to develop newer functional materials through defect engineering by suitable dopants toward superior performances in environment issues.

Core-shell alpha-Fe2O3-ZnO structures of different nanotextured morphology were synthesized through wet chemical routes using different solvents like ethanol, ethanolamine, water and acetaldehyde. Morphological tuning using different solvents resulted in the formation of different shapes, such as disc, spindle, rod and sphere (abbreviated as FZ-ND, FZ-NSP, FZ-NR and FZ-NS, respectively). Structural, morphological and compositional characterization of these nanoparticles (NPs) has been carried out. Antibacterial efficacy of the synthesized NPs was checked against Gram negative V. cholerae N16961 (VcN16961) and Gram positive S. aureus bacteria by recording optical density (OD) at different time points. Among the NPs tested, FZ-NSP was found to be the most effective against VcN16961, while FZ-NR showed maximum efficacy against S. aureus, implying the importance of nanotextured surface as well as the morphology in the manifestation of antibacterial activity. The kinetics of growth for both the bacteria has been modelled using logistic approach. Cytotoxicity was evaluated through MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide) assay against human breast adenocarcinoma-cell line (MCF-7), human hepatocarcinoma cell line (HepG2) and against normal human embryonic kidney cell line (HEK-293). The lesser toxicity of alpha-Fe2O3-ZnO towards HEK-293 and the potent anticancer activity against MCF-7 and HepG2 cells underline its applicability as anticancer agent. With continued improvement of nanotechnology, this study may pave the way for designing and construction of various morphologically diverse, nanotextured materials with desired functional attributes.

The need of multifunctional advanced materials facilitating clean and sustainable environment is the key issue from the perspective of materials scientists. This study demonstrates facile and scalable synthesis of MoS2 with different amount of TiO2 loading and its effect on the hydrogen evolution reaction through electrochemical water splitting. The synthesized composites, with different loading of TiO2 on MoS2 were examined by XRD, XPS, SEM and TEM for structural, chemical and morphological details. The electrocatalytic measurement shows the significant current density for hydrogen evolution reaction from these hybrid series recording the best one as 40mA/cm(2) at overpotential of 0.64 V vs. RHE. Thus the presented MoS2-TiO2 hybrid structures with different TiO2 loading show huge potential in the search of efficient HER performing catalysts for the application in the clean energy technology in future.

In this report, an effort has been made to develop an efficient PbS quantum dot-sensitized photoanode by simple successive ionic layer adsorption and reduction technique to enhance the overall photovoltaic performance of PbS quantum dot-sensitized solar cells. Three strategies have been adopted for the improvement of the photovoltaic performance of PbS quantum dot-sensitized solar cells, i.e., (i) by incorporation of TiO2-Au nanocomposites, where Au nanoparticles of different sizes are embedded into a TiO2 matrix, and (ii) variation of temperature at which quantum dots are deposited (iii) by postdeposition annealing of QD-sensitized photoanode in Ar atmosphere. We have used electrophoretic deposition technique to develop the nanocomposite-doped photoanode. High-resolution transmission electron microscopy confirms that the Au particles dispersed in the TiO2 matrix vary from 2 to 50 nm and PbS quantum dot size ranges 3.5–6 nm. The optical absorption of PbS quantum dot-sensitized TiO2-Au-incorporated photoanode is substantially enhanced as confirmed from the UV-visible absorption spectra measurements. The current-voltage characteristics of all the plasmonic quantum dot-sensitized solar cells under illumination (100 mW/cm2, AM 1.5) show significant improvement in power conversion efficiency using the abovementioned strategies. The maximum power conversion efficiency observed in PbS quantum dot-based quantum dot-sensitized solar cells is 7.0%. Electroimpedance spectroscopy has been utilized to understand the recombination kinetics in these solar cells.