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Journal of the American Chemical Society 145(2), 1433 - 1440 (2023). doi:10.1021/jacs.2c12366, The scientific community has found immense difficulty to focus on the generation of chiral intermetallics compared to the chiral molecular structure, probably due to the technical difficulty in producing them as no general controlled protocol is available. Herein, using a conventional metal flux technique, we have discovered a new ternary intermetallic Co$_3$Ni$_3$Ga$_8$, substituting Co at the Ni sublattice in a highly symmetric Ni$_3$Ga$_4$ (Ia$\bar{3}$d). Co$_3$Ni$_3$Ga$_8$ crystallizes in the I4$_1$32 space group, a Sohncke type, and can host the chiral structure. To the best of our knowledge, this is the first report of a ternary intermetallic crystallizing in this space group. The chiral structure of Co$_3$Ni$_3$Ga$_8$ is comprehensively mapped by various techniques such as single-crystal X-ray diffraction (XRD), synchrotron powder XRD, X-ray absorption spectroscopy (XAS), scanning transmission electron microscopy (STEM) and theoretically studied using density functional theory. The discovery of this chiral compound can inspire the researchers to design hidden ternary chiral intermetallics to study the exotic electrical and magnetic properties., Published by ACS Publications, Washington, DC

A novel type-II composite heterostructure obtained by combining earth-abundant, non-toxic, cost-effective red phosphorus and Bi2MoO6 selectively converts CO2 to ethanol using sunlight and water.

This work reports the development of metal nanoparticles dispersed over Schiff base functionalized SBA-15. Tuning the hybridization favours optimum CO2 capture and charge polarization at metal nanoparticles enhances the conversion of CO2 to formic acid.

TiO2 was activated for visible light driven CO2 reduction in the presence of Bi2MoO6 as an electron donor. The introduction of oxygen vacancies enhanced the CO2 to methanol conversion.

We present surface reconstruction-induced C-C coupling leads to conversion of CO2 to Ethylene. Wurtzite phase of CuGaS2. undergoes in-situ surface reconstruction leads to the formation of a thin CuO layer over the pristine catalyst which facilitates selective conversion of CO2 to ethylene (C2H4). Upon illumination, the catalyst efficiently converts CO2 to C2H4 with 75.1% selectivity (92.7% selectivity in terms of Relectron) and 20.6 µmol g-1 h-1 evolution rate. Subsequent spectroscopic and microscopic studies supported by theoretical analysis found the operando generated Cu2+ with the assistance of existing Cu+anchored the generated *CO, facilitating the C-C coupling. This study demonstrates the strain-induced in-situ surface reconstruction leading to heterojunction formation accounting for fine-tuning of the oxidation state of Cu that modulate CO2 reduction reaction pathway to selective formation of ethylene, which opens a new footstep to achieve CO2 to C2+ hydrocarbons.

The development of earth-abundant, cost-effective electrocatalysts for the hydrogen evolution reaction (HER) is essential for the production of hydrogen. Structural transitions and generation of de...

The well-known limitation of alkaline fuel cells is the slack kinetics of the cathodic half-cell reaction, the oxygen reduction reaction (ORR). Platinum, being the most active ORR catalyst, is still facing challenges due to its corrosive nature and sluggish kinetics. Many novel approaches for substituting Pt have been reported, which suffer from stability issues even after mighty modifications. Designing an extremely stable, but unexplored ordered intermetallic structure, Pd

The activity of Pt towards oxygen reduction reaction (ORR) can be enhanced by alloying it with secondary metals. They can be grouped into three different classes: alloys, bimetallics and intermetallics. Although alloys and bimetallics exhibit enhanced performance, often they are limited by metal dissolution and resulted in poor durability. This invokes the need on the development of ordered intermetallics. In this minireview we comprehensively present the recent progress and developments of Pt3 X alloys and intermetallics towards ORR. Additionally, major technical challenges and possible future research directions to overcome these challenges are discussed to facilitate further research in this area.

The discovery of new materials for efficient transformation of carbon dioxide (CO2) into desired fuel can revolutionize large-scale renewable energy storage and mitigate environmental damage due to carbon emissions. In this work, we discovered an operando generated stable Ni–In kinetic phase that selectively converts CO2 to methanol (CTM) at low pressure compared to the state-of-the-art materials. The catalytic nature of a well-known methanation catalyst, nickel, has been tuned with the introduction of inactive indium, which enhances the CTM process. The remarkable change in the mechanistic pathways toward methanol production has been mapped by operando diffuse reflectance infrared Fourier transform spectroscopy analysis, corroborated by first-principles calculations. The ordered arrangement and pronounced electronegativity difference between metals are attributed to the complete shift in mechanism. The approach and findings of this work provide a unique advance toward the next-generation catalyst discovery for going beyond the state-of-the-art in CO2 reduction technologies.

A facile non-template-assisted mechanical ball milling technique was employed to generate a PdBi alloy catalyst. The induced lattice strain upon the milling time caused a shift of the d-band center...

CO2 capture is one of the cardinal technologies to combat the ever-escalating CO2 concentration in the atmosphere and to address global climate change. Among the several strategies employed, adsorption on porous solid seems to be a promising alternative to conventional CO2 capture technologies. However, to employ this technology in real-world CO2 capture conditions, the stability of the adsorbent materials under humid conditions is of paramount importance. To date, several CO2 sorbent materials are reported to show remarkable CO2 uptake capacities both by physical and chemical adsorption. Nevertheless, the stability of many of these superior adsorbents in humid conditions is questionable. This is a key reason that hinders its commercial exploration in real flue gas conditions. The systematic tuning of material properties such as porosity, wettability, hydrophobicity and functionalization strategies can play a decisive role in enhancing the material stability and CO2 sorption capacity. Herein, we present a comprehensive review of the trends and innovations in CO2 capture in humid conditions. Various materials and methodologies employed for CO2 capture from the humid stream are extensively reviewed. In particular, some of the key strategies such as tuning the hydrophobicity, amine modifications, introduction of polar functional groups, water enhanced CO2 uptake are discussed in detail. We believe the present review can lead this emerging field to develop state-of-the-art materials that can have a potential future in real-world CO2 capture technologies.

Increased level of CO2 in the atmosphere is identified as a threat to life on the planet earth. Since hydrogenation of CO2 back to fuel is identified as a major solution for both decreasing the emission and meeting the energy demands, the energy-efficient capture of CO2 is recognized as the inevitably significant step. Small and large scale direct air capture of CO2 (DAC) is a viable solution to address CO2 discharge from industrial, automobile, and household activities (both point and mobile sources). The real challenge of DAC is to pick 400 molecules of CO2 for capture from a million gas molecules in the atmosphere. Thus, in this report, we focus on reviewing the literature dealing with the chemical interaction between sorbate (CO2) and sorbent which is highly specific. Materials such as metal hydroxides and amine solutions are well discussed in other celebrated reviews and perspectives. Here we focus on inert porous silica immobilized amine material emphasizing particularly on their advantages compared to other sorbent materials. Furthermore, amines functionalized novel silica materials like bimodal porous silica, hierarchical silica are discussed highlighting the CO2 capture mechanism, desorption, and sorbent-regeneration. Both O2 and CO2-induced degradation pathways along with measures to retard sorbent degradations are presented. Finally, a brief overview of sustainability and future potential of amine-silica composite material is presented for more insights.

Ultra low PtPd alloy deposited on Ni12P5 nanostructures (PtPd/Ni12P5) exhibited enhanced ORR activity (onset: 1.003 V and E1/2:0.95 V) on par with commercial Pt/C and superior OER activity with 81% reduction of the precious metal compared to the commercial catalyst.

Sodium-ion batteries (SIBs) have emerged as a potential alternative to lithium-ion batteries (LIBs), which is attributed to their cost-effectiveness and the natural abundance of sodium in the Earth's crust. However, constrained by their low energy density and poor cycling stability, the development of highly efficient anode materials for SIBs is the need of the hour. Solid-state alloying reactions can be beneficial to enhancing energy density and hence metal alloy based anode materials are considered as emerging materials for SIBs. Antimony (Sb) is one of the most important SIB anode materials owing to its high theoretical capacity and judicious reaction potential. Hence, Sb-based alloys and intermetallics have also evolved as potential candidates for SIBs. However, the major development is impeded by the volume changes associated with the sodiation/desodiation reaction. In this review we place emphasis on Sb based alloys and intermetallics and have summarized recent developments in this field of energy storage. Herein, we have discussed design strategies, developments made so far, the probable challenges and relevant mitigation-related issues associated with Sb based alloys and intermetallics.

The rational design of efficient electrode materials for fuel cells, water oxidation, and metal–air batteries is now cutting-edge activity in renewable energy research. In this regard, tuning activity at the molecular level is one of the most challenging problems. Here, we have strategically employed two isophthalate-based ligands to tune the molecular structure and chemical bonding of three Co-based MOFs at the atomic level. MOFs were well characterized by single-crystal X-ray diffraction, IR spectroscopy, and X-ray absorption spectroscopy. The assembly of Co in these three novel MOFs at the atomic level dictates the catalytic activity towards the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). The catalytic activity of these MOFs has been boosted further upon annealing thereby forming highly efficient noble-metal-free Co-single atom catalysts where the amount of cobalt is extremely low.

The discovery of novel materials for industrial-standard hydrogen production is the present need considering the global energy infrastructure. A novel electrocatalyst, Pt

Enhancing oxygen reduction (ORR) activity through alloying is crucial to improve the performance of a fuel-cell catalysts. In this work, we have studied the alloying effects of 4f rare-earth (RE) m...

Electrode materials based on antimony (Sb) are of growing interest as Sb achieves a balance between high capacity and good cycle performance in battery operation. The electrochemical performance of...

In this study, we report an enormously simple green approach for the synthesis of polyaniline hybrid (PANI-SO) nanofibers in emeraldine salt form. We have carried out the synthesis via an interfacial polymerization method using vegetable oil as an organic phase instead of the commonly used solvents like CHCl3, CCl4, etc. Characterization techniques such as Fourier transform infrared (FTIR), UV–visible, powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) have been used for studying the synthesized polyaniline hybrid nanofibers. An interesting observation is the crystallization of small organic molecules in the PANI matrix. PANI-SO shows a pseudocapacitance behavior with a capacitance value of 302 F g–1 at a current density of 1 A g–1. In addition, the material shows an energy density of 26.8 W h kg–1 and a maximum power density of 402.6 W kg–1. Furthermore, the PANI-SO electrode maintains about 84% of the initial capacitance after 1000 cycles. Similarly, the PANI-SO symmetric solid-state supercapacitor shows an areal capacitance of 118.7 mF cm–2 and retains a stability of 80% even after 1000 cycles. Thus, the PANI-SO electrode shows a good cyclic performance, which implies the structural stability of PANI-SO nanofibers. The electrochemical properties of PANI-SO are compared with those of PANI nanofibers synthesized by taking CHCl3 as the organic phase and keeping all other parameters identical. PANI-SO is observed to be a superior material compared to the latter one. All electrochemical analyses show that the PANI synthesized using cooking soyabean oil (PANI-SO) is an effective supercapacitor material.

In Co3O4 systems, the oxygen vacancy is reported to improve the oxygen evolution reaction (OER) activity because of higher Co2+/Co3+ surface ratio. In situ studies have revealed Co3+—site reducibil...

The use of hydrogen, being the environmentally cleaner source of energy, may reduce the pressing problem of CO2 emissions due to the burning of conventional fossil fuels. However, prolonged product...

The cornerstone of the emerging hydrogen economy is hydrogen production by water electrolysis with concomitant oxygen generation. Incorporating a third element in metal phosphides can tune the crys...

Understanding the descriptors of electrochemical activity and ways to modulate them are of paramount importance for the efficient structural engineering of electrocatalysts. Although, many studies separately elucidated the significance of thermodynamic and kinetic descriptors, lack of integrative approaches bars the potential utilization of these engineering tools for electrocatalytic activity enhancement. Here, through a facile post-carbonization synthetic technique using templated polyoxometalate based metal organic frameworks (POMOFs), we integrate three major structural engineering tools, viz. phase, size and strain into cost-effective Mo and W carbide electrocatalysts, and demonstrate how these factors qualitatively and quantitatively affect the critical descriptors of electrochemical activity. Deconvolution of these effects through combined experimental-theoretical analyses, shines new light on structure-activity relationships in this class of HER electrocatalysts. Optimum modulation of the structural tools culminated into the design of a superior electrocatalyst, consisting of ultrasmall γ-WC nanocrystals supported on N doped graphitic carbon that exhibited multifold activity enhancement in terms of onset potential, current density and Tafel slope compared to its structural analogues reported in this work and elsewhere. The present comprehensive study showcasing the effects of the structural engineering tools on activity will have considerable influence on future designs of more efficient nano-composite electrocatalysts.

We report a novel s-tetrazine based covalent organic framework (TZA-COF) and its hybrid nanocomposites with reduced graphene oxide (TZA-COF-rGO) and Co metal to illustrate novel structure-activity relationships in this class of compounds for electrocatalytic oxygen reduction reaction (ORR). The Co-impregnated hybrid composites (TZA-COF-rGO-Co) were further annealed to yield Co-encapsulated nitrogen doped graphitic carbon (Co@NC-600), which exhibited excellent ORR activity comparable to that of the state-of-the art Pt/C in terms of onset potential, E1/2 (half-wave potential), 4e- reduction selectivity and methanol tolerance. Sequential mechanistic analyses of activity enhancement and electron transfer pathways for the ORR, at different stages of controlled catalyst engineering, elucidated the crucial role of active sites and overall catalyst nature in tuning the ORR mechanism. Co@NC-600 also exhibited high oxygen evolution reaction (OER) activity under alkaline conditions which makes it one of the most efficient non-precious metal bifunctional catalysts, capable of catalyzing complex 4e- reduction processes like the ORR and OER.

Chemistry of materials 34(19), 8999 - 9008 (2022). doi:10.1021/acs.chemmater.2c02667, Electrochemical water reduction is one of the cleanest ways to produce hydrogen efficiently. Non-noble metal-based intermetallic compounds, particularly Ni-based ones, can be projected as potential water electrocatalysts because of Ni’s low cost and high abundance. In this work, Ni’s crystal structure and electronic properties have been tuned by introducing Sn metal followed by operando structural transformation. The synthetically tuned deficiency of Ni in Ni$_{2–x}$Sn (x = 0.35, 0.50, and 0.63) and operando-induced phase transformation of the room temperature orthorhombic Cmcm space group (Ni$_{2–x}$Sn_RT) to the high-temperature hexagonal P6$_3$/mmc space group (Ni$_{2–x}$Sn_HT) enhance the hydrogen evolution. Several controlled synthesis and electrochemical measurements indicate that Ni$_{1.5}$Sn_HT is the most active and stable HER catalyst because of its unique crystallographic structure and high charge transfer kinetics. The phase Ni$_{1.5}$Sn_RT was electrochemically transformed to the HT phase during the HER process and found to be extremely stable (150 h) in the chronoamperometric study., Published by American Chemical Society, Washington, DC

Intermetallic compounds (IMCs) have diverse electronic and geometrical properties to offer. However, the synthesis of intermetallic nanoparticles is not always easy; developing new methodologies th...

Development of highly active and stable low-cost Pt-free catalysts for ethanol electrooxidation (EOR) in alkaline medium has drawn a lot of attention in recent years. Palladium-based catalysts are ...

We present results on growth of ReS2 thin film both on c plane sapphire substrate and MoS2 template by pulsed laser deposition (PLD). Films tend to grow with (0001)ReS2 ⊥ (0001)Al2O3 and (0001)ReS2 ⊥ (0001)MoS2 ∥ (0001)Al2O3 at deposition temperature below 300 °C. Films are polycrystalline grown at temperature above 300 °C. The smoothness and epitaxial quality of the films are significantly improved when grown on MoS2 template compared to sapphire substrate. The results show that PLD is suitable to grow ReS2 thin film over large area (10 × 10 mm2) for practical device application.