Publications by authors named "Ramendra Sundar Dey"

We have developed two triazole-based covalent organic polymers (COPs) with donor-acceptor motifs. The keto-enriched COP demonstrated exceptional oxygen activation electrochemical stimuli, driven by strong push-pull interactions. studies and DFT calculations confirmed the critical role of enamine carbon positive charges in enhancing performance, setting new benchmarks in COP design.

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Ultrasmall nanoparticles on nanocarbons enhance the electrocatalytic nitrogen reduction (NRR) efficiency. Herein, we demonstrate a novel method for depositing MoO nanoparticles on defective graphene, achieving a high faradaic efficiency (FE) of 43.1% at -0.

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Electrocatalytic nitrogen oxidation reaction (NOR) offers a sustainable alternative to the conventional methods such as the Haber-Bosch and Ostwald oxidation processes for converting nitrogen (N) into high-value-added nitrate (NO ) under mild conditions. However, the concurrent oxygen evolution reaction (OER) and inefficient N absorption/activation led to slow NOR kinetics, resulting in low Faradaic efficiencies and NO yield rates. This study explored oxygen-vacancy induced tin oxide (SnO-O) as an efficient NOR electrocatalyst, achieving an impressive Faradaic efficiency (FE) of 54.

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The promising features of aqueous zinc ion batteries (AZIBs), including their inherent safety, environmental friendliness, abundant raw materials, cost-effectiveness, and simple manufacturing process, position them as strong candidates for large-scale energy storage. However, their practical application faces significant challenges, such as uncontrolled dendritic growth, undesirable side reactions, and hydrogen evolution reactions (HER), which undermine the efficiency and longevity of the system. To address these issues, extensive research has been conducted to improve these batteries' energy density and lifespan.

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Doping is considered a promising material engineering strategy in electrochemical nitrogen reduction reaction (NRR), provided the role of the active site is rightly identified. This work concerns the doping of group VIB metal in AgPO to enhance the active site density, accompanied by d-p orbital mixing at the active site/N interface. Doping induces compressive strain in the AgPO lattice and inherently accompanies vacancy generation, the latter is quantified with positron annihilation lifetime studies (PALS).

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Electrocatalytic nitrogen fixation to ammonia (NH), a precursor for fertilizer production and a promising energy carrier, has garnered widespread interest as an environment-friendly and sustainable alternative to the energy-intensive fossil-feedstock-dependent Haber-Bosch process. The large-scale deployment of this process is contingent on the identification of inexpensive, Earth-abundant systems that can operate efficiently, irrespective of the electrolyte pH for the selective production of NH. In this regard, we discuss the scalable synthesis of VO anchored on N-doped carbon (VO2@CN), and its applicability as a robust electrocatalyst for the nitrogen reduction reaction (NRR).

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Oxygen vacancy engineering has recently been gaining much interest as the charging effect it induces in a material can be used for varied applications. Usually, semiconductor materials act poorly in electrocatalysis, particularly in the nitrogen reduction reaction (NRR), owing to their inherent charge deficit and huge band gap. Vacancy introduction can be a viable material engineering route to make use of these materials for the NRR.

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Strategic modulation of the electronic structure of the catalyst to foster the electrochemical nitrogen reduction reaction (eNRR) to the ammonia process significantly is still an area that needs to be explored. Herein, we report the incorporation of the Lewis acid into an electron-rich copper site regulating the electron density of the metal, which has been experimentally proved from the d-band center position to have a direct influence on the adsorption of N compared to the protons. The catalyst boron doped copper-cuprous oxide hybrid system (B-Cu/CuO) has shown promising Faradaic efficiency of 32% at -0.

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Noble metal-based catalyst, despite their exorbitant cost, are the only successful catalyst for bifunctional oxygen electrocatalysis owing to their capability to drive forward the reaction rate kinetically. Therefore, it is desirable to diminish the noble metal loading without any compromise in the catalyst performance. In this study, the aim to achieve two goals with one action via a single-step route to have ultra-low loading of Pd in the catalyst.

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Laser-irradiated graphene-based heterostructures have attracted significant attention for the fabrication of highly conducting and stable metal-free energy storage devices. Heteroatom doping on the graphene backbone has proven to have better charge storage properties. Among other heteroatoms, nitrogen-doped graphene (NG) has been extensively researched due to its several advanced properties while maintaining the original characteristics of graphene for energy storage applications.

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Ammonia is a crucial biochemical raw material for nitrogen containing fertilizers and a hydrogen energy carrier obtained from renewable energy sources. Electrocatalytic ammonia synthesis is a renewable and less-energy intensive way as compared to the conventional Haber-Bosch process. The electrochemical nitrogen reduction reaction (eNRR) is sluggish, primarily due to the deceleration by slow N diffusion, giving rise to competitive hydrogen evolution reaction (HER).

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Extensive research on the electrochemical nitrogen reduction reaction (NRR) has put forward a sound list of potential catalyst materials with properties inducing N adsorption, protonation, and reduction. However, rather than a random selection of catalysts, it is essential to understand the vitals in terms of orbital orientation and charge distribution that actually manipulate the rate-determining steps of NRR. Realizing these factors, herein we have explored a main group earth-abundant Mg-based electrocatalyst MgBO for NRR due to the abundance of Lewis acid sites in the catalyst favoring the bonding-antibonding interactions with the N molecules.

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The development of affordable and non-noble-metal-based reversible oxygen electrocatalysts is required for renewable energy conversion and storage systems like metal-air batteries (MABs). However, the nonbifunctionality of most of the catalysts impedes their use in rechargeable MAB applications. Moreover, the loss of active sites also affects the long-term performance of the electrocatalyst toward oxygen electrocatalysis.

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Electrochemical nitrogen reduction reaction (NRR) is imperatively countered with the oxygen evolution reaction (OER) on a conventional Pt counter electrode. Upon focusing on the development of suitable cathode catalysts, it is usually overseen that OER on Pt seeks a significant energy input to overcome the slow reaction kinetics, regardless of the efficiency of the NRR catalyst. Here, we unveil an out-of-the-box concept with state-of-the-art catalysts that, on pursuing OER with RuO2 in KOH, the NRR process reinforces thermodynamically.

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Engineering catalytically active sites have been a challenge so far and often relies on optimization of synthesis routes, which can at most provide quantitative enhancement of active facets, however, cannot provide control over choosing orientation, geometry and spatial distribution of the active sites. Artificially sculpting catalytically active sites via laser-etching technique can provide a new prospect in this field and offer a new species of nanocatalyst for achieving superior selectivity and attaining maximum yield via absolute control over defining their location and geometry of every active site at a nanoscale precision. In this work, a controlled protocol of artificial surface engineering is shown by focused laser irradiation on pristine MoS flakes, which are confirmed as catalytic sites by electrodeposition of AuNPs.

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Ammonia has been recognized as the future fuel because of its immense advantages over liquid hydrogen. The research trend nowadays is mostly inclined toward the electrochemical ammonia synthesis since it offers a sustainable method of green ammonia production. The indophenol blue method is one of the largely used colorimetric techniques to detect ammonia spectroscopically but lacks a proper experimental protocol.

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Ammonia has been recognized as the future renewable energy fuel because of its wide-ranging applications in H storage and transportation sector. In order to avoid the environmentally hazardous Haber-Bosch process, recently, the third-generation ambient ammonia synthesis has drawn phenomenal attention and thus tremendous efforts are devoted to developing efficient electrocatalysts that would circumvent the bottlenecks of the electrochemical nitrogen reduction reaction (NRR) like competitive hydrogen evolution reaction, poor selectivity of N on catalyst surface. Herein, we report the synthesis of an oxygen-functionalized boron carbonitride matrix via a two-step pyrolysis technique.

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Electrocatalytic hydrogen evolution reaction (HER) via water electrolysis has been considered the most effective and sustainable route to produce clean hydrogen. Designing and structure optimization are the two important parameters to develop an affordable, easy to fabricate, and stable non-noble metal electrocatalyst for the production of hydrogen as a clean, sustainable, and green fuel. Herein, we have synthesized Ni-Mo-P on copper foam (Cuf) via a facile single-step electrodeposition method, which can show stratospheric efficiency toward HER with a Tafel slope of 67 mV dec and a very low overpotential of only 53 mV at a current density of 20 mA cm.

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Tin-based materials with high specific capacity have been studied as high-performance anodes for Li-ion storage devices. Herein, a mix-phase structure of SnO-SnO@rGO (rGO = reduced graphene oxide) was designed and prepared via a simple chemical method, which leads to the growth of tiny nanoparticles of a mixture of two different tin oxide phases on the crumbled graphene nanosheets. The three-dimensional structure of graphene forms the conductive framework.

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The development of a cost-effective, remarkably competent, and durable bifunctional electrocatalyst is the foremost requirement of water splitting to generate H fuel as a renewable energy technology. Three-dimensional porous copper foam (Cuf) when electrochemically decorated with transition metal selenide results in a highly active electrocatalyst for adequate water electrolysis. In terms of water splitting, the role of cobalt selenide and Cuf has already proven to be remarkable.

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The growing demands for ammonia in agriculture and transportation fuel stimulate researchers to develop sustainable electrochemical methods to synthesize ammonia ambiently, to get past the energy-intensive Haber-Bosch process. However, the conventionally used aqueous electrolytes limit N solubility, leading to insufficient reactant molecules in the vicinity of the catalyst during electrochemical nitrogen reduction reaction (NRR). This hampers the yield and production rate of ammonia, irrespective of how efficient the catalyst is.

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An effective modulation of the active sites in a bifunctional electrocatalyst is essentially desired, and it is a challenge to outperform the state-of-the-art catalysts toward oxygen electrocatalysis. Herein, we report the development of a bifunctional electrocatalyst having target-specific Fe-N/C and Co-N/C isolated active sites, exhibiting a symbiotic effect on overall oxygen electrocatalysis performances. The dualism of N-dopants and binary metals lower the d-band centers of both Fe and Co in the Fe,Co,N-C catalyst, improving the overpotential of the overall electrocatalytic processes (Δ = 0.

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A new significant feature of a triazine-based covalent organic polymer electrocatalyst is demonstrated. The metal-free electrocatalyst has dual-active sites, which enable it to entangle oxygen a push-pull interaction that plays a crucial role in promoting the oxygen reduction reaction.

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Towards rational catalyst development, a binary Fe-Co centre has been coordinated with S and N in a nanocarbon matrix. An electronic drift between Fe-Co and an extended +R effect from the S dopants towards the metals through the p orbital of N are beneficial for oxygen electrocatalysis and a zinc-air battery.

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The development of an efficient, sustainable, and inexpensive metal-free catalyst for oxygen evolution reaction (OER) photoelectrochemical water splitting is very demanding for energy conversion processes such as green fuel generators, fuel cells, and metal-air batteries. Herein, we have developed a metal-free pyrene-based nitrogen and sulfur containing conjugated microporous polymer having a high Brunauer-Emmett-Teller surface area (761 m g) and a low bandgap of 2.09 eV for oxygen evolution reaction (OER) in alkaline solution.

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