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The present work quantifies metal-contaminant interactions between palladium substrates and three salient chlorinated organic contaminants, namely trichloroethylene 1,3,5-trichlorobenzene (TCB), and 3,3′,4,4′-tetrachlorobiphenyl (PCB77). Given that Pd is one of the conventional catalytically active materials known for contaminant removal, maximizing catalytic efficiency through optimal adsorption dynamics reduces the cost of remediation of contaminants that are persistent water pollutants chronically affecting public health. Adsorption efficiency analyses from all-atom molecular dynamics (MD) simulations advance the understanding of reaction mechanisms available from density functional theory (DFT) calculations to an extractable feature scale that can fit the parametric design of supported metal catalytic systems and feed into high throughput catalyst selection. Data on residence time, site-specific adsorption, binding energies, packing geometries, orientation profiles, and the effect of adsorbate size show the anomalous behaviour of organic contaminant adsorption on the undercoordinated {110} surface as compared to the {111} and {100} surfaces. The intermolecular interaction within contaminants from molecular dynamics simulation exhibits refreshing results than ordinary single molecule density functional theory calculation. Since complete adsorption and dechlorination is an essential step for chlorinated organic contaminant remediation pathways, the presented profiles provide essential information for designing efficient remediation systems through facet-controlled palladium nanoparticles.

Present study investigates techno-economic feasibility of trimellitic acid (TMLA) production from a biorenewable precursor 5-hydroxymethyl furfural (HMF) for the first time. A 5 kmol/hr HMF feed rate to produce 99% pure TMLA is considered to provide a roadmap for fixing the minimum sales price of TMLA for significant return on investments and a shorter payback period. The current TMLA sales price varies significantly ($10/kg–$1000/kg) in different markets; depending on the process for TMLA production. Thus, techno-economic feasibility study for TMLA production is investigated considering variable sales price. It is also observed that two distinct reaction routes for TMLA production from HMF are possible and both routes can be profitable even at the minimum sales price of $10/kg. Nevertheless, TMLA production from direct conversion of HMF showed better internal rate of return (IRR) (105.94%) than the one calculated for a two-step process (39.42%). It is also observed that catalyst and raw materials costs are main contributing factor in capital and operating costs, respectively. Thus, cost of feed is varied to study the possible future cases, as HMF cost may decrease with advances in the development of biomass conversion technologies. It is observed that the IRR of the TMLA production plant would further increase significantly by ∼16% if raw material cost is reduced by 10–40% in the future.

Hydric alcohols are important synthetic intermediates used to manufacture polymer, fine chemicals, and commodity products. Recent environmental problems due to fossil fuel-based non-degradable products have call for the advancement in research towards developing an alternate source that can sustainably substitute petroleum. In this direction, we have conceptualized a combined fermentation and catalytic process to obtain biorenewable branched diols from biomass. The significant yield of the desired diol products was obtained from different lignocellulose-based cyclic esters under optimized conditions. In order to know the universality of our process, saturated, partially saturated and unsaturated lactones were tested, which gave up to 99% conversion and (∼68–91%) diol’s yield. Finally, a plausible mechanism for 6-amyl-α-pyrone hydrogenation is proposed which is more likely to follow a pathway involving ring-opening reaction via partial hydrogenation of the double bond.

The present work explores the application of La0.5Sr0.5Co0.95Nb0.05O3-δ (LSCNO) perovskite as electrode material for the symmetric solid oxide fuel cell. Symmetric solid oxide fuel cells of thin-film LSCNO electrodes were prepared to study the oxygen reduction reaction at intermediate temperature. The Rietveld refinement of synthesized material shows a hexagonal structure with the R-3c space group of the prepared perovskite material. Lattice parameter and fractional coordinates were utilized to calculate the oxygen ion diffusion coefficient for molecular dynamic simulation. At 973 K, the oxygen ion diffusion of LSCNO was 1.407 × 10−8 cm2 s−1 higher by order of one magnitude than that of the La0.5Sr0.5CoO3-δ (7.751 × 10−9 cm2 s−1). The results suggest that the Nb doping provide the structural stability which improves oxygen anion diffusion. The enhanced structural stability was analysed by the thermal expansion coefficient calculated experimentally and from molecular dynamics simulations. Furthermore, the density functional theory calculation revealed the role of Nb dopant for oxygen vacancy formation energy at Sr–O and La–O planes is lower than the undoped structure. To understand the rate-limiting process for sluggish oxygen diffusion kinetics, 80 nm and 40 nm thin films were fabricated using radio frequency magnetron sputtering on gadolinium doped ceria electrolyte substrate. The impedance was observed to increase with an increasing thickness, suggesting the bulk diffusion as a rate-limiting step for oxygen ion diffusion. The electrochemical performance was analysed for the thin-film symmetric solid oxide fuel cell, which achieved a peak power density of 390 mW cm−2 at 1.02 V in the presence of H2 fuel on the anode side and air on the cathode side.

260-GHz radiation is used for a quasi-optical electron spin resonance (ESR) spectrometer which features both field and frequency modulation. Free space propagation is used to implement Martin-Puplett interferometry with quasi-optical isolation, mirror beam focusing, and electronic polarization control. Computer-aided design and polarization pathway simulation lead to the design of a compact interferometer, featuring lateral dimensions less than a foot and high mechanical stability, with all components rated for power levels of several Watts suitable for gyrotron radiation. Benchmark results were obtained with ESR standards (BDPA, DPPH) using field modulation. Original high-field ESR of 4f electrons in Sm3+-doped Ceria was detected using frequency modulation. Distinct combinations of field and modulation frequency reach a signal-to-noise ratio of 35 dB in spectra of BDPA, corresponding to a detection limit of about 1014 spins.

Abstract Aqueous rechargeable mixed‐ion batteries (ARMBs), where two types of ions shuttle between the cathode and anode, are an important alternative to conventional non‐aqueous electrolyte‐based rechargeable batteries. Herein, we present fundamental insights into the function of an ARMB comprising of NASICON‐based sodium titanium phosphate (NaTi2(PO4)3/NTP) and olivine‐based lithium iron phosphate (LiFePO4/LFP) employed as the anode and cathode respectively in combination with mixed‐ion electrolytes, x‐M Li2SO4: y‐M Na2SO4 (x+y=1). Electrochemical and ex situ structural studies interestingly reveal a preferential Na+‐ion insertion into NTP, despite the presence of two different cations in the electrolyte. This is strongly supported by molecular dynamics simulations, which show a 1–2 orders higher diffusion coefficient for Na+‐ion than Li+‐ion in NTP. In contrast, co‐insertion of Li+ and Na+‐ions into LFP takes place when cycled in mixed‐ion electrolytes. We also show that batteries with mixed‐ion electrolytes perform better than electrolytes with individual cations.

The synthesis of syngas (H 2  : CO=2) via catalytic partial oxidation of methane (CPOM) is studied over noble metal doped Ni-CeO 2 bimetallic catalysts for CPOM reaction. The catalysts were synthesized via a controlled deposition approach and were characterized using XRD, BET-surface area analysis, H 2 -TPR, TEM, Raman and TGA analysis. The catalysts were experimentally and computationally studied for their activity, selectivity, and long-term stability. Although the pure 5Ni/CeO2 catalyst showed high initial activity (∼90%) of CH 4 conversion, it rapidly deactivates around 20% of its initial activity within 140 hours of TOS. Doping of Ni/CeO 2 catalyst with noble metal was found to be coke resistant with the best-performing Ni-Pt/CeO 2 catalyst showed ∼95% methane conversion with >90% selectivity at a temperature of 800 °C, having exceptional stability for about 300 hours of time-on-stream (TOS). DFT studies were performed to calculate the activation barrier for the C-H activation of methane over the Ni, Ni 3 Pt, Ni 3 Pd, and Ni 3 Ru (111) surfaces showed nearly equal activation energy over all the studied surfaces. DFT studies showed high coke formation tendency of the pure Ni (111) having a very small C-C coupling activation barrier (14.2 kJ/mol). In contrast, the Ni 3 Pt, Ni 3 Pd, and Ni 3 Ru (111) surfaces show appreciably higher C-C coupling activation barrier (∼70 kJ/mol) and hence are more resistant against coke formation as observed in the experiments. The combined experimental and DFT study showed Ni-Pt/CeO 2 as a promising CPOM catalyst for producing syngas with high conversion, selectivity and long-term stability suited for future industrial applications., (© 2023 Wiley-VCH GmbH.)

Cobalt and iron metal-based oxide catalysts play a significant role in energy devices. To unravel some interesting parameters, we have synthesized metal oxides of cobalt and iron ( i.e. Fe 2 O 3 , Co 3 O 4 , Co 2 FeO 4 and CoFe 2 O 4 ), and measured the effect of the valence band structure, morphology, size and defects in the nanoparticles towards the electrocatalytic hydrogen evolution reaction (HER), the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR). The compositional variations in the cobalt and iron precursors significantly alter the particle size from 60 to <10 nm and simultaneously the shape of the particles (cubic and spherical). The Tauc plot obtained from the solution phase ultraviolet (UV) spectra of the nanoparticles showed band gaps of 2.2, 2.3, 2.5 and 2.8 eV for Fe 2 O 3 , Co 3 O 4 , Co 2 FeO 4 and CoFe 2 O 4 , respectively. Further, the valence band structure and work function analysis using ultraviolet photoelectron spectroscopy (UPS) and core level X-ray photoelectron spectroscopy (XPS) analyses provided better structural insight into metal oxide catalysts. In the Co 3 O 4 system, the valence band structure favors the HER and Fe 2 O 3 favors the OER. The composites Co 2 FeO 4 and CoFe 2 O 4 show a significant change in their core level (O 1s, Co 2p and Fe 2p spectra) and valence band structure. Co 3 O 4 shows an overpotential of 370 mV against 416 mV for Fe 2 O 3 at a current density of 2 mA cm -2 for the HER. Similarly, Fe 2 O 3 shows an overpotential of 410 mV against the 435 mV for Co 3 O 4 at a current density of 10 mA cm -2 for the OER. However, for the ORR, Co 3 O 4 shows 70 mV improvement in the half-wave potential against Fe 2 O 3 . The composites (Co 2 FeO 4 and CoFe 2 O 4 ) display better performance compared to their respective parent oxide systems ( i.e. , Co 3 O 4 and Fe 2 O 3 , respectively) in terms of the ORR half-wave potential, which can be attributed to the presence of the oxygen vacancies over the surface in these systems. This was further corroborated in density functional theory (DFT) simulations, wherein the oxygen vacancy formation on the surface of CoFe 2 O 4 (001) was calculated to be significantly lower (∼50 kJ mol -1 ) compared to Co 3 O 4 (001). The band diagram of the nanoparticles constructed from the various spectroscopic measurements with work function and band gap provides in-depth understanding of the electrocatalytic process.