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The study of polaron dynamics in complex materials has garnered significant attention owing to its implications for various technological applications, including catalysis, solid‐state devices, and energy storage. This paper investigates the photo‐excited electron and hole polaron dynamics in cerium dioxide (CeO2) using time‐resolved X‐ray absorption spectroscopy, with an emphasis on the nano‐size effect. Additionally, density functional theory and multiplet calculations have been utilized to reveal the photo‐excited polaron dynamics in CeO2 single crystal (SC) and nanocrystal (NC). The electron polaron is observed to decay into a deep trap site with a short duration of ≈5 ps, while electrons in the traps stay for more than 1400 ps. The most significant observation is the behavior of holes in NC, which tends to stay longer (≈150 ps) compared to SC (<10 ps) suggesting hole existence more at the surface than at bulk. The fast dissociation of the electron polarons the prolonged lifetime of the electrons above the Fermi level and the enhanced hole lifetime at the surface are proposed to be among the various factors that influence the high reactivity of CeO2. [ABSTRACT FROM AUTHOR]

Hydrolysis of magnesium (Mg) or their composites are considered as an efficient, economical and enabling technique to produce hydrogen (H 2). In this study, carbon nano-tube coated with iron carbide (CNT@Fe 3 C) was synthesized and applied as a catalyst to promote hydrolysis of Mg to generate H 2. Ball milling technique was employed to prepare Mg-Xwt%CNT@Fe 3 C (X = 0.2, 2.0, 5.0 and 10.0) composites for hydrolysis in seawater. Among employed composites, the results demonstrated that the introduction of small amount of CNT@Fe 3 C promote the hydrolysis kinetics of Mg. Particularly, Mg-5.0 wt%CNT@Fe 3 C composite ball milled for 1 h released 866.5 mL/g H 2 with 10072.0 mLg−1min−1 initial hydrogen generation rate mHGR and demonstrated an excellent composite. Furthermore, activation energy of Mg hydrolysis kinetic dropped to 23.6 kJ/mol. Hence, CNT@Fe 3 C inhibited the magnesium hydroxide (Mg(OH) 2) from sticking to the unreacted Mg surfaces, which enhanced its galvanic corrosion and reactivity. In order to develop portable H 2 generators, CNT@Fe 3 C supported Mg system can provide clean H 2 to reduce the adverse environmental effect. [Display omitted] • CNT@Fe 3 C promote the hydrolysis kinetics of magnesium (Mg). • Effect of ball milling on the hydrolysis performance of Mg-CNT@Fe 3 C composite. • Formation of cracks and micro galvanic cell promoted the hydrolysis kinetics. • The CNT@Fe 3 C coupled Mg has potential use in large-scale hydrogen production. [ABSTRACT FROM AUTHOR]

This study is a pioneering study that experimentally and theoretically measures the effect of heterogeneous catalyst structure on hydrogen production. In this research, the catalytic activity of the (CQD/GO@Co) catalyst, which was formed by doping Co onto the synthesized graphene oxide (GO) on carbon quantum dots (CQD) obtained from caffeine by green synthesis, was investigated. The catalyst CQD/GO@Co was synthesized with high dispersibility and activity, and it was successfully employed in the hydrolysis of NaBH 4 for the first time. The effective catalytic compatibility of caffeine and cobalt element increased approximately 3 times on the GO layer. In order to determine the most effective catalyst conditions in the study, NaOH concentration, catalyst amount, NaBH 4 amount and temperature were tested under different reactant conditions. The catalyst was characterized using X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET) analyses. Field emission scanning electron micrographs (FESEM) were taken by Field emission scanning electron microscope (Zeiss, Sigma). Energy dispersive X-ray (EDX) spectra were obtained from Energy dispersive X-ray spectroscope. According to spherical aberration transmission electron microscopy studies, the uniform dispersion of Co nanoparticles (average diameter: ±3,1 nm) on CQDs, as well as the very small size and good dispersion of Cobalt (Co), are conducive to improved catalytic performance. This situation was determined by molecular modeling with the Non-scc GFN1xTB model and results supporting the experimental data were obtained. The maximum hydrogen production rate with sodium borohydride hydrolysis using cobalt-based catalyst increased approximately 32 times (from metallic crystal form of Co catalyst 2860 mL/min.(g.cat) to the present form 49,044 mL/min.(g.cat). The activation energy, activation enthalpy, and activation entropy of the Co@CQDs catalyst were founded to be 20.65 kJ mol−1, 2.64 kJ mol−1, and -108,97 J mol−1, respectively. • The study highlights the importance of the orientation of caffeine with the cobalt metal ion as a catalysis. • As the amount of sodium element with large van der Waals radius increases, positive blocks forms in solution. • Hydrolysis increases the interactions with high electrical dipole moments that occur with high vibration frequencies. [ABSTRACT FROM AUTHOR]

In this study, multi-walled carbon nanotubes (MWCNTs) were synthesized using the arc discharge method, and gold (Au) , and Au@MWCNT nanoparticles (NPs) were obtained via a rapid and cost-effective chemical reduction method. The performance of these catalysts in ethylene glycol (EG) fuel cells was investigated. According to the Transmission Electron Microscope (TEM) results, the Au particle size was determined to be 3.89 nm, and the MWCNT diameter was found to be 8.21 nm. For EG oxidation, current densities of 33.28 mA/cm2 for Au NPs and 171.28 mA/cm2 for Au@MWCNT NPs were obtained. This result demonstrates that the MWCNT support increased the electrocatalytic activity by a factor of 5.14. Long-term stability tests showed that the MWCNT support exhibited more stable and consistent characteristics and improved CO tolerance. Electrochemical Impedance Spectroscopy (EIS) testing revealed that the MWCNT-supported structure significantly enhanced charge transfer. These findings contribute significantly to the literature by demonstrating the potential for cost-effective production of carbon supported Au NPs, and their application in fuel cells. • MWCNT production using arc-discharge method. • Preparation of Au and Au@MWCNT catalysts and their use in ethylene glycol oxidation studies. • Au@MWCNT exhibits superior electrocatalytic activity towards ethylene glycol oxidation. • Synthesis of more stable catalyst for ethylene glycol oxidation. • Anode catalyst showing high potential for fuel cell applications. [ABSTRACT FROM AUTHOR]

The oxygen evolution reaction (OER) is a primary bottleneck that disturbs the efficient hydrogen production from water using renewable electricity. Despite extensive studies, current benchmark NiFe oxyhydroxide catalysts need further development to reduce significant overpotentials for efficient OER. Here, we show that an oxalate-derived OER catalyst immediately converted to NiFe hydroxides in KOH is a promising candidate as a suitable OER catalyst. We find the significant influence of varying water content on morphological changes and Fe dispersion, impacting the intrinsic OER kinetics of the catalysts. Furthermore, the synthesis temperature proves crucial in controlling oxalate growth rates and suppressing Fe penetration into the bulk region of oxalates, resulting in a more uniform formation and widespread distribution of surface Fe sites. The optimized catalyst exhibits remarkable and stable catalytic performance, recording a current density of 200 mA cm⁻2 at an overpotential of 320 mV for 300 h. We present the significant influence of varying water content and synthesis temperature on nano-sized oxalate growth, consequently impacting the OER. [Display omitted] • The NiFe oxalate rapidly transforms into nanostructured NiFe oxyhydroxides upon immersion in KOH for OER. • The synthetic temperature and solution composition effects for the in-situ growth of oxalate are identified. • Microscopic and in-situ spectroscopic evidence revealed the nature of the catalyst phase and compositions. • The nano-pyramid-like oxalate exhibits the best catalytic performance. [ABSTRACT FROM AUTHOR]

The increasing demand for hydrogen as a clean energy carrier, driven by global efforts to mitigate climate change and reduce reliance on fossil fuels, necessitates advancing efficient hydrogen production technologies. Membrane reactors, at the forefront of these technologies, offer a promising avenue for enhancing hydrogen production through integrating novel catalysts, innovative membrane designs, and utilizing renewable energy sources. This review explores the latest developments in membrane reactor technology, highlighting the synergistic application of advanced catalysts and membrane designs to improve hydrogen yield and efficiency. Integrating renewable energy sources is especially emphasized to achieve sustainable hydrogen production, alongside exploring nanotechnology to introduce new materials and configurations that elevate hydrogen generation. This review further explores the advancements in high-temperature membrane reactors, unlocking significant improvements in operational efficiency and the purity of the produced hydrogen. Moreover, it explores the up-and-coming potential of green chemistry for developing eco-friendly hydrogen production methods and optimizing these membrane reactors through advanced control strategies. A particular focus is given to the bio-hydrogen production and the application of mixed ionic-electronic conductors to elevate the reactor performance further. • Increasing demand for hydrogen drives advancements in efficient production technologies. • Membrane reactors enhance hydrogen yield and efficiency using novel catalysts and innovative designs. • Integrating renewable energy sources into membrane reactors achieves sustainable hydrogen production. • Nanotechnology introduces new materials and configurations for improved hydrogen generation. [ABSTRACT FROM AUTHOR]

This computational study explores the copper (I) chloride catalyzed synthesis of (E)‐1‐(2,2‐dichloro‐1‐phenylvinyl)‐2‐phenyldiazene (2Cl‐VD) from readily available hydrazone derivative and carbon tetrachloride (CCl4). 2Cl‐VD has been extensively utilized to synthesize variety of heterocyclic organic compounds in mild conditions. The present computational investigations primarily focus on understanding the role of copper (I) and N1,N1,N2,N2‐tetramethylethane‐1,2‐diamine (TMEDA) in this reaction, TMEDA often being considered a proton scavenger by experimentalists. Considering TMEDA as a ligand significantly alters the energy barrier. In fact, it is only 8.3 kcal/mol higher compared to the ligand‐free (LF) route for the removal of a chlorine atom to form the radical ·CCl3 but the following steps are almost barrierless. This intermediate then participates in attacking the electrophilic carbon in the hydrazone. Crucially, the study reveals that the overall potential energy surface is thermodynamically favorable, and the theoretical turnover frequency (TOF) value is higher in the case of Cu(I)‐TMEDA complex catalyzed pathway. [ABSTRACT FROM AUTHOR]

[Display omitted] The high theoretical energy density and specific capacity of lithium-sulfur (Li-S) batteries have garnered considerable attention in the prospective market. However, ongoing research on Li-S batteries appears to have encountered a bottleneck, with unresolved key technical challenges such as the significant shuttle effect and sluggish reaction kinetics. This investigation explores the catalytic efficacy of three catalysts for Li-S batteries and elucidates the correlation between their structure and catalytic impacts. The results suggest that the combined utilization of lithium-insertion technology and a proton exchange approach for δ-MnO 2 can optimize its electronic structure, resulting in an optimal catalyst (H/Li inserted δ-MnO 2 , denoted as HLM) for the sulfur reduction reaction. The replacement of Mn sites in δ-MnO 2 with Li atoms can enhance the structural stability of the catalyst, while the introduction of H atoms between transition metal layers contributes to the satisfactory catalytic performance of HLM. Theoretical calculations demonstrate that the bond length of Li 2 S 4 adsorbed by the HLM molecule is elongated, thereby facilitating the dissociation process of Li 2 S 4 and enhancing the reaction kinetics in Li-S batteries. Consequently, the Li-S battery utilizing HLM as a catalyst achieves a high areal specific capacity of 4.2 mAh cm−2 with a sulfur loading of 4.1 mg cm−2 and a low electrolyte/sulfur (E/S) ratio of 8 μL mg−1. This study introduces a methodology for designing effective catalysts that could significantly advance practical developments in Li-S battery technology. [ABSTRACT FROM AUTHOR]

Herein, three g-C3N4(MCN/TCN/UCN), obtained by the direct pyrolysis of melamine/urea/thiourea respectively, were introduced as supports to optimize the NH3-SCR activity of Ce-W-Ti catalyst. Compared to CWT-400-Air, CWT@g-C3N4(2)-300-N2 exhibits lower crystalline anatase TiO2 and larger specific surface area, which improves the dispersion of Ce/W/Ti species on catalysts surface. Furthermore, the introduction of g-C3N4 as supports also contributes to doping C/N elements into Ce-W-Ti catalyst and increases the Ce3+/(Ce3++Ce4+) and Oα/(Oα+Oβ) molar ratios on catalyst surface. These all are advantageous to the NH3-SCR activity. However, UCN shows better promotional effect than MCN and TCN. This might be mainly attributed to the loose and porous stacked layered fold structure of UCN, the larger BET surface area, higher dispersion of Ce/W/Ti species and moderate weak/medium-strong acid sites of CWT@UCN(2)-300-N2. At the same time, the influence of carbon nitride amount, calcination atmosphere and calcination temperature on the NH3-SCR activity of CWT@g-C3N4 catalyst were also investigated. [ABSTRACT FROM AUTHOR]

In order to ensure operational efficiency and safety, the flow dynamics of the ortho-para hydrogen converter in a liquid hydrogen system was studied. The precise selection of filtration accuracy stands as a critical factor in maintaining system stability and reliability. Unforeseen pressure drops within the filter layer hinted at microchannel blockages. Electron microscopy inspection and test result analysis suggested adhesion of catalyst particles to microfiltration channel surfaces within the filter layer. Experimental data and fluid dynamics analyses were utilized to reconstruct actual effective microchannel apertures under diverse temperature and fluid settings, unveiling a gradual narrowing mechanism of microchannels in colder temperatures. Enhanced magnetism exhibited by catalyst and filter materials at lower temperatures emerged as a major driver behind magnetic adhesion, significantly contributing to microchannel constriction. Besides magnetic forces, fluid-solid interface tensions influenced the flow dynamics within liquid hydrogen microchannels, leading to heightened particle adhesion and consequent dimensional reductions in surface channels. Successful adjustments in filtration accuracy substantially alleviated the ortho-para converter's resistance from over 100 kPa–22 kPa. This research bears profound implications for the widespread application of liquid hydrogen systems. • Catalyst resistance is crucial to the operability and reliability of liquid hydrogen systems. • Catalyst dust adhesion blockages lead to variable flow resistance. • Adhesion mechanisms consisted of liquid-solid tension, magnetic and electrostatic forces. • Observed cryogenically enhanced magnetism effects were for 316L stainless steel and catalyst. • Actual filtration precision exceeds nominal values, recommended precision 5–25 μm for catalyst. [ABSTRACT FROM AUTHOR]

Nitride-based MXenes materials are promising for advancing technological developments, especially in popular scientific fields such as energy storage and conversion. This study successfully synthesized 2D lamellar Ti 2 NTx MXenes via selective etching of Al from the Ti 2 AlN MAX phase. Synthesized Ti 2 NT x MXene was characterized by field emission scanning electron microscope with energy-dispersive X–Ray spectroscopy attachment (FESEM-EDX), X-ray diffraction (XRD), X–Ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), and Brunauer–Emmett–Teller (BET) analyses techniques in details. 2D lamellar morphology of MXene phase was observed with FESEM, while distinctive diffraction peaks were confirmed with XRD analyses. While the BET surface area of the MAX phase was 0.5375 m2/g, it was measured as 2.0867 m2/g with Ti 2 NT x MXene which increased by 3.88 times. Ti–O–N, Ti–N, and surface functional groups (T x : OH, –F, –O) of Ti 2 NT x MXenes were revealed with XPS analyses. (112) crystal plane associated interplanar d-space (0.243 nm) was observed with HRTEM results. The electrocatalytic activity of synthesized Ti 2 NT x MXene was investigated by hydrazine electrooxidation. The Ti 2 NT x electrocatalyst exhibited a specific activity of 2.739 mA/cm2 and mass activity of 44.1 mA/mg for hydrazine electrooxidation. Ti 2 N also showed long-term stability compared to Ti 2 AlN. [Display omitted] • Ti 2 AlN MAX Phases was successfully prepared using ball mill and sintering methods. • Novel Ti 2 NTx 2D lamella structural MXene Phases was prepared after acidic exfoliation of Al layer from Ti 2 AlN MAX phases. • The Structural and morphological characterization of MXene material were discussed. • The hydrazine electrooxidation performance of prepared novel Ti 2 NTx 2D MXene was investigated. [ABSTRACT FROM AUTHOR]

Stimuli-responsive catalysts with exceptional kinetics and complete recoverability for efficient recyclability are essential in, for example, converting pollutants and hazardous organic compounds into less harmful chemicals. Here, we used a novel approach to stabilize silver nanoparticles (NPs) through magneto/hydro-responsive anionic polymer brushes that consist of poly (acrylic acid) (PAA) moieties at the amine functional groups of chitosan. Two types of responsive catalyst systems with variable silver loading (wt.%) of high and low (PAAgCHI/Fe3O4/Ag (H, L)) were prepared. The catalytic activity was evaluated by monitoring the reduction of organic dye compounds, 4-nitrophenol and methyl orange in the presence of NaBH4. The high dispersity and hydrophilic nature of the catalyst provided exceptional kinetics for dye reduction that surpassed previously reported nanocatalysts for organic dye reduction. Dynamic light scattering (DLS) measurements were carried out to study the colloidal stability of the nanocatalysts. The hybrid materials not only showed enhanced colloidal stability due to electrostatic repulsion among adjacent polymer brushes but also offered more rapid kinetics when compared with as-prepared Ag nanoparticles (AgNPs), which results from super-hydrophilicity and easy accumulation/diffusion of dye species within polymer brushes. Such remarkable kinetics, biodegradability, biocompatibility, low cost and facile magnetic recoverability of the Ag nanocatalysts reported here contribute to their ranking among the top catalyst systems reported in the literature. It was observed that the apparent catalytic rate constant for the reduction of methyl orange dye was enhanced, PAAgCHI/Fe3O4/Ag (H) ca. 35-fold and PAAgCHI/Fe3O4/Ag (L) ca. 23-fold, when compared against the as prepared AgNPs. Finally, the regeneration and recyclability of the nanocatalyst systems were studied over 15 consecutive cycles. It was demonstrated that the nanomaterials display excellent recyclability without a notable loss in catalytic activity. [ABSTRACT FROM AUTHOR]

A series of basic functional ionic liquids were prepared from 1, 4-diazabicyclo [2.2.2] octane (DABCO) with various halogenated hydrocarbons, then these functional ionic liquids were used as catalysts for the chemical fixation of CO2 into cyclic carbonates and the influence of the structure of the ionic liquids was investigated. The results showed that the N atom active center, types of anions and hydrogen bond of the catalyst play a key role in the cycloaddition reaction of CO2 with epoxides to cyclic carbonates. Under mild reaction conditions (T = 100 °C, 1 atm CO2), the ionic liquid [DABCO-CH2CH2CH2OH] I showed the best catalytic effect, which has notable advantages such as high catalytic activity, eco-friendly, ease of work-up and convenient reuse. [ABSTRACT FROM AUTHOR]

Magnesium dichloride (MgCl2)-supported titanium catalyst with diisobutyl phthalate (DIBP) and 3,5-di-isopropyl 1,2-phenylene diethyl dicarbonate (CD1, non-phthalate) internal donor was synthesized using magnesium alkoxide precursor. Additionally, a catalyst without the internal donor was prepared for comparative analysis. The synthesized catalysts were characterized and compared with respect to composition, surface area, particle size and morphology. The effect of CD1-based magnesium dichloride-supported Z–N catalyst was investigated for propylene polymerization and compared with DIBP-based and without internal donor Z–N catalyst system. The catalyst system with the CD1 internal donor demonstrated a higher MFI in the resultant polypropylene, suggesting a superior hydrogen response during propylene polymerization compared to both the DIBP-based and the donor-free catalyst systems. The molecular weight of the polymer was studied through gel permeable chromatography and compared for all catalyst system. The scanning electron microscope image of the polymer resin indicates spherical morphology and exact replication of catalyst. Catalyst systems exhibiting such elevated hydrogen responses hold significant industrial relevance, especially demand of high MFI PP grades in the automotive industry. [ABSTRACT FROM AUTHOR]

In this study, a natural zeolite supported Co-B catalyst (Co-B/Zeolite) with a Co content of 10 wt.% was prepared by impregnation and chemical reduction method to release hydrogen gas from an alkaline sodium borohydride (NaBH4) solution. The synthesized catalyst was characterized with various characterization techniques, including X-ray diffraction (XRD), X-ray fluorescence (XRF), inductively coupled plasma mass spectroscopy (ICP-MS), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS), etc. It was found that the BET specific surface area of Co-B/Zeolite (26.03 m2 g−1) was roughly double that of the zeolite (13.12 m2 g−1). The Co ratio in the catalyst was found to be 12.02 wt.% by EDX analysis. ICP-MS examination of the catalyst revealed a B/Co atomic ratio of 0.64. No peaks associated with Co-B were observed in the XRD pattern of the catalyst, indicating the amorphous nature of the component. Parameters that have significant effects on the hydrolysis reaction, such as catalyst amount, sodium hydroxide and sodium borohydride concentrations, and reaction temperature, were investigated. The hydrogen generation rate (HGR) was found to be 1732 mL min−1 gcat−1 in the presence of 100 mg of Co-B/Zeolite in 5 wt.% NaOH and 5 wt.% NaBH4 solution at 50 °C. The experimental results were well fitted to the zero-order kinetic model (k0 = 0.0296–0.1619 mol min−1 gcat−1 for 20–50 °C). The activation energy (Ea) of the catalytic reaction was found to be 44.98 kJ mol−1. Meanwhile, the reusability evaluations showed that the catalyst preserves high stability and can still sustain 73% of its initial activity after 5 catalytic cycles. [ABSTRACT FROM AUTHOR]

Features of the catalytic action of Pd–Ag, Pd–Cu, Pd–Au, Pd–Ga, and Pd–Zn bimetallic systems on the acetylene conversion to ethylene are discussed taking into account two factors that determine the effect of the second metal on palladium, namely, the "ensemble effect" (geometric effect) and the "ligand effect" (electronic effect). The relationship between the calculated thermodynamic and kinetic parameters of the adsorption interaction of major reaction medium components and intermediates with the catalyst surface, the structure of active ensembles, and characteristics determined in tests, such as the structural parameters of bimetallic phases, the electronic state of their components, and catalytic properties, is shown. Some examples are given to show that the modifier atoms can be incorporated into active ensembles and the sites formed by the modifier atoms can be involved in the catalysis of individual elementary steps. [ABSTRACT FROM AUTHOR]

The main patterns of oxidative chlorination (oxychlorination) with such unsaturated hydrocarbons as propylene, acetylene, 1,3-butadiene, and benzene are considered. It is shown that when the processes are conducted in the gas phase, having heterogeneous copper or palladium based catalysts in the system is preferable. It is shown that palladium in a catalyst promotes processes of substitutive oxychlorination. Stagewise schemes of reactions are given for processes of propylene, acetylene, and benzene oxychlorination along with corresponding kinetic equations. Applied aspects of the above processes are discussed. [ABSTRACT FROM AUTHOR]

The author considers the main patterns characteristic of the processes of hydrogen chloride oxidation (the Deacon reaction) and oxidative methane and ethane chlorination. It is shown that the most widely recognized and best studied catalysts of these processes are copper chloride systems that are based on different supports and contain alkali and rare-earth metal chlorides, which reduce the entrainment of an active phase from the surface of a catalyst with a simultaneous increase in its activity. The prospects for using ruthenium catalysts are also noted. The main kinetic and technological patterns of oxychlorination are considered. Conditions are described that allow the yield of target products (lower methane chlorides) to be increased in the oxychlorination of methane and vinyl chloride during the oxychlorination of ethane. Variants of reactor units for oxychlorination are proposed. [ABSTRACT FROM AUTHOR]

α-AlH3 is regarded as one of the most promising hydrogen storage materials due to its high hydrogen storage capacity (10.1 wt.%, 148 kg·m−3). However, in practical applications, the associated hydrogen release temperature remains relatively high. To effectively address this issue, hollow structured Fe@C nanorods derived from Fe-MOF are introduced as highly efficient catalyst to optimize the dehydrogenation properties of α-AlH3. Comparatively, the initial hydrogen release temperature of α-AlH3 + 3 wt.% Fe@C is reduced to 94.2 °C, which is significantly lower than that of pure α-AlH3 (137.8 °C). At 100 and 120 °C, it exhibits hydrogen capacities of 5.38 wt.% and 7.47 wt.%, respectively, whereas pure α-AlH3 only delivers hydrogen capacities of 0.24 wt.% and 5.94 wt.% under the same temperatures. The density functional theory (DFT) calculations further indicate that the existence of Fe@C catalyst can make the length of Al–H bond increase, which is more conducive to the release of hydrogen. The results show that the synergistic effect of Fe and porous carbon in Fe@C nanorods can improve the hydrogen desorption kinetics of α-AlH3, providing a good prospect for the application of α-AlH3 in hydrogen storage fields. [ABSTRACT FROM AUTHOR]

Rechargeable Li‒O2 batteries have attracted considerable attention owing to their high specific energy density compared to those of other lithium secondary batteries. However, the high charging overpotential remains one of the challenges for the application of Li-O2 batteries in specific energy storage systems. To solve this problem, various catalyst materials such as metal/metal oxides (Pt, Au, MnO2, CuO, etc.) have been developed. In this study, a new CaCO3 catalyst embedded in carbon is investigated for the first time for a nonaqueous Li‒O2 battery application. The overpotential of the Li‒O2 cell containing the CaCO3-embedded carbon cathode decreases by ~ 6.5% on an average over 40 cycles. [ABSTRACT FROM AUTHOR]

The high demand for biofuels by surfacing economies with environmental issues has resulted in a more in‐depth search for new biofuel feedstocks. Non‐edible oils have become the centre of investigation as biofuel feedstocks since they do not compete with food sources. This review evaluates hydrocracking as a biofuel production method and further elucidates different feedstocks, the effects of hydrocracking catalysts, and operating parameters to obtain optimum yields and selectivity of desired products. The bifunctional catalyst mechanism is also explained. The hydrocracking technique is found to be more advantageous than other biofuel production techniques such as transesterification and pyrolysis due to its ability to produce valuable products of better quality and with higher yields. Coke formation is one of the challenges faced by hydrocracking despite that it can be reduced by high hydrogen pressure; this will increase the cost of the entire process. [ABSTRACT FROM AUTHOR]

The utilization of fossil fuels has been the leading choice in the industrial revolution despite its negative environmental impact. Biodiesel is a well-known alternative to replace fossil fuels because it is a renewable and environmentally friendly fuel. The use of biodiesel increases every year, causing new problems. The transesterification reaction to produce biodiesel also produces a by-product of glycerol. Glycerol is among the world's 12 most essential chemical raw materials. The abundance of glycerol has not been followed by the level of consumption, so it is necessary to increase the value of the glycerol. The transformation of glycerol into high-value-added chemicals is a promising solution to utilizing abundant glycerol. Glycerol transformation can be done through several reaction pathways catalyzed by zeolite. Zeolite is a heterogeneous catalyst with acid-base sites and good framework selectivity, making it suitable for catalytic glycerol transformation. Zeolite can be used to catalyze glycerol through various reactions into high-value-added chemicals such as glycerol oxidation to produce dihydroxyacetone, glycerol hydrogenolysis to produce propylene glycol, glycerol dehydration to produce acrolein, glycerol transesterification with dialkyl carbonate to produce glycerol carbonate, glycerol pyrolysis to produce syngas, and glycerol etherification to produce glycerol ethers. Statement of Novelty: This review highlights the current approaches to upgrade the value of glycerol, a by-product of biodiesel production, through catalytic transformation using zeolite as a heterogeneous catalyst. The catalytic processes of glycerol over zeolite with unique nanopore architectures with abundant acid sites could address the surplus glycerol problem enabling the production of high-value-added chemicals. Moreover, based on the current development, this review also provides areas of future research. [ABSTRACT FROM AUTHOR]

The innovation of high‐performance, stable electrocatalysts for clean energy systems faces significant challenges. Metal‐organic frameworks (MOFs), with their porous nature, flexible structures, and homogeneous active site dispersion, have gained interest as unique precursors for carbon‐based catalysts. MOFs' properties significantly enhance catalytic performance in fuel cells. This review highlights recent advancements in MOF design for oxygen electrocatalysis in fuel cells, while also discussing perspectives for future material innovations to improve catalytic activity in this emerging field. [ABSTRACT FROM AUTHOR]

\nIn this study, solid acid magnetic nanoparticles Fe3O4@SiO2-S-Bu-SO3H were prepared under appropriate conditions and characterized by various analytical techniques including FT-IR, XRD, FE-SEM, EDX, and VSM. Finally, the catalytic activity of the synthesized Fe3O4@SiO2-S-Bu-SO3H MNPs was investigated for the synthesis of valuable benzothiazole derivatives by the condensation reaction of ortho-aminothiophenol and various aldehydes under ultrasonic conditions. In the presence of the inexpensive, environment-friendly, magnetically recoverable solid acid catalyst, the benzothiazoles were obtained as pure target products in excellent yields (90–98%) and short reaction times (3–11 min). The synthesized Fe3O4@SiO2-S-Bu-SO3H MNPs show great catalytic activity because of the combined effect of Brønsted acidity and high functional group density. This solid acid magnetic nanocatalyst is reusable for several cycles and can be easily segregated from the reaction mixture.In this research, we have successfully developed ultrasonic assisted a green and efficient methodology for the synthesis of the 2-substituted benzothiazole derivatives using MNPs Fe3O4@SiO2-S-Bu-SO3H as a low-cost, environment-friendly, and reusable catalyst with excellent yields and very short reaction times. [ABSTRACT FROM AUTHOR]

ABSTRACT The development of hydrogenation processes for polyalphaolefin (PAO) lubricants, which hold commercialization potential, is a challenging endeavor. Here, we synthesized and characterized rod‐shaped γ‐alumina supported Pd catalyst for PAO hydrofinishing, comparing it with γ‐alumina supported Ni catalyst. Results indicated that Pd/Al2O3 catalyst efficiently promoted PAO hydrofinishing, whereas Ni‐based catalyst exhibited lower activity. Optimization of reaction variables using the one‐factor‐at‐a‐time method revealed that hydrogenated polyalphaolefin could be achieved with a 90% yield using a 5 wt.% catalyst, a hydrogen pressure of 12 bar, at 130°C after 7 h. The superior performance of the fabricated catalysts, coupled with the use of rod‐shaped alumina suitable for large‐scale hydrogenation reactors, suggests the versatility of the process for potential commercialization. Additionally, the higher performance of Pd/alumina compared to Ni/alumina catalyst was computationally assessed at the molecular level using DFT methods. [ABSTRACT FROM AUTHOR]

Thermochemical conversion of agricultural by-products into hydrogen-rich syngas is a technology that offers both economic and environmental benefits. In this work, we investigated a biochar-supported nickel-based catalyst for the catalytic pyrolysis of straw biomass to produce hydrogen-rich syngas. The by-product, straw biochar, was used as a material for synthesizing fresh catalysts, achieving a closed-loop process. We explored gas yields under various conditions. The highest yields of CO and H 2 , reaching 0.52 L/g and 0.48 L/g, respectively, were obtained under the conditions of a pyrolysis temperature of 900 °C, a residence time of 20 min, a calcination temperature of 400 °C, a nickel loading of 15 wt%, and a citric acid to potassium hydroxide ratio of 1:4. The catalysts were characterized using XRD, H 2 -TPR, SEM, and TEM. The results demonstrated that biochar provides excellent support and synergy, enabling the catalyst to function at high temperatures and offering antioxidative protection to the active metals during the thermal process. Overall, this catalytic pyrolysis process, aiming for green and efficient conversion, achieved high yields of syngas and hydrogen. • Biochar provides anti-oxidation protection for active metals. • Biochar-supported Ni catalyst shows high load capacity and synergy. • Utilizing biochar byproduct to synthesize fresh catalyst, enhancing syngas yield. [ABSTRACT FROM AUTHOR]

In this paper, we report an inexpensive one-step synthesis of self-supported 3D nickel-manganese (NiMn) bimetallic coatings and their application for the hydrogen evolution reaction in simulated seawater (1 M KOH + 0.5 M NaCl) and alkaline natural seawater (1 M KOH + natural seawater). These binary coatings were electrodeposited on a titanium substrate using a facile electrochemical deposition method by a dynamic hydrogen bubble template technique. The as-deposited NiMn coatings with variable Mn amounts produce typical globular and unique porous architecture with abundant pores of different sizes. The activity of these fabricated catalysts towards the hydrogen evolution reaction was investigated by linear sweep voltammetry towards simulated seawater and alkaline natural seawater at different temperatures. The surface morphology and composition of the catalysts were also characterized by scanning electron microscopy and inductively coupled plasma optical emission spectroscopy. The as-prepared NiMn/Ti electrocatalyst, which was electrodeposited using a chemical bath containing Ni2+ and Mn2+ ions with a molar ratio of Ni2+:Mn2+ = 1:5, exhibits excellent hydrogen evolution activity in simulated seawater with an ultra-low overpotential of 64.2 mV to reach a current density of 10 mA cm−2. It is noteworthy that this NiMn/Ti electrocatalyst also achieves a current density of 10 mA cm−2 in alkaline natural seawater with a comparably low overpotential of 79.3 mV. The current densities increase by ca. 1.75–2.35 times with an increase in temperature from 25 °C to 75 °C for hydrogen evolution in both electrolytes. This bimetallic catalyst has shown excellent long-term stability at a constant potential of −0.23 V (vs. RHE) and a constant current density of 10 mA cm−2 for 10 h, which ensures higher durability and robustness for practical application of seawater splitting technology. [Display omitted] • 3D bimetallic NiMn/Ti electrocatalysts synthesized using a dynamic hydrogen bubble template technique. • Efficient and stable 3D bimetallic NiMn/Ti electrocatalysts for HER in simulated seawater/alkaline natural seawater. • NiMn/Ti-5 shows excellent HER activity with overpotentials of 64.2 and 79.3 mV at 10 mAcm−2 in simulated and natural seawater. • Simple, non-toxic, affordable, and time-saving synthesis procedure. [ABSTRACT FROM AUTHOR]

The gasochromic properties of WO 3 thin films deposited by electron beam evaporation were investigated, focusing on their structural, morphology and optical changes caused by heat treatment. Moreover, the influence of the thickness and type of catalyst on the gasochromic properties of WO 3 was examined. X-ray diffraction measurements revealed that WO 3 thin films annealed up to 473 K remained amorphous, whereas annealing at 673 K and above, initiated crystallization into a monoclinic structure. Gasochromic behaviour was observed in response to hydrogen exposure, with the most significant changes occurring in films annealed at 673 K with a thin adlayer of palladium catalyst. A gasochromic response of 1.84 was achieved for H 2 concentration as low as 25 ppm. The process of gasochromic colouration was correlated with the changes of free charge carrier concentration calculated based on Drude free electron theory. XPS analysis confirms WO 3 reduction under hydrogen exposure, validating proposed colouration mechanisms. These comprehensive findings offer insights into optimizing gasochromic thin films for various sensing applications. [Display omitted] • Thermal treatment at 673 K enhanced a gasochromic response of WO 3. • Type and thickness of catalyst influenced on gasochromic response of WO 3. • Very high gasochromic response of 1.84 for WO 3 was obtained for 25 ppm of H 2. • Free charge carrier concentration in WO 3 films increased after exposure to H 2. • XPS revealed that tungsten oxidation state decreased upon exposure to H 2. [ABSTRACT FROM AUTHOR]

Liquid organic hydrogen carrier (LOHC) technology has unique advantages in hydrogen storage and transportation. However, the lack of research on the continuous dehydrogenation process of LOHCs has hindered the design and application of industrial dehydrogenation processes. In this work, a highly active dehydrogenation catalyst 1.5 wt% Pd/activated carbon (Pd/C) and a commercial catalyst 5 wt% Pd/Al2O3 were used for the continuous dehydrogenation of dodecahydro‐N‐ethylcarbazole (12H‐NEC). Based on a tubular reactor and lab‐scale apparatus, 1.5 wt% Pd/C catalyst achieved a maximum dehydrogenation conversion of 98.3% and a maximum NEC selectivity of 95.3%, while dehydrogenation conversion and NEC selectivity with 5 wt% Pd/Al2O3 were 98.3% and 97.6%, respectively. It showed the equally excellent performance between Pd/C and Pd/Al2O3, and the former has less Pd loading than the latter, with the potential of reducing the production cost of the dehydrogenation catalyst. The dehydrogenation results also indicated the difference in catalytic performance between the two kinds of catalysts. The obtained kinetics data were analyzed, and the dynamics of continuous dehydrogenation were studied to provide fundamental information for dehydrogenation scale‐up. [ABSTRACT FROM AUTHOR]

The presented research is the seed of a vision for the development of a waste-for-product strategy. Following this concept, various synthetic solutions containing low concentrations of platinum group metals were used to model their recovery and to produce catalysts. This is also the first report that shows the method for synthesis of a pyramid-like structure deposited on activated carbon composed of Pd and Pt. This unique structure was obtained from a mixture of highly diluted aqueous solutions containing both metals and chloride ions. The presence of functional groups on the carbon surface and experimental conditions allowed for: the adsorption of metal complexes, their reduction to metal atoms and enabled further hierarchical growth of the metal layer on the carbon surface. During experiments, spherical palladium and platinum nanoparticles were obtained. The addition of chloride ions to the solution promoted the hierarchical growth and formation of palladium nanopyramids, which were enriched with platinum nanoparticles. The obtained materials were characterized using UV–Vis, Raman, IR spectroscopy, TGA, SEM/EDS, and XRD techniques. Moreover, Pd@ROY, Pt@ROY, and Pd-Pt@ROY were tested as possible electrocatalysts for hydrogen evolution reactions. [ABSTRACT FROM AUTHOR]

Efficient hydrogen storage and transportation are crucial for the sustainable development of human society. Ammonia, with a hydrogen storage density of up to 17.6 wt%, is considered an ideal energy carrier for large-scale hydrogen storage and has great potential for development and application in the "hydrogen economy". However, achieving ammonia decomposition to hydrogen under mild conditions is challenging, and therefore, the development of suitable catalysts is essential. Metal oxide-based catalysts are commonly used in the industry. This paper presents a comprehensive review of single and composite metal oxide catalysts for ammonia decomposition catalysis. The focus is on analyzing the conformational relationships and interactions between metal oxide carriers and active metal sites. The aim is to develop new and efficient metal oxide-based catalysts for large-scale green ammonia decomposition. [ABSTRACT FROM AUTHOR]

This work investigates the potential of ZrO 2 /MoO 3 nanocomposites as catalysts for hydrogen production through NaBH 4 methanolysis. The samples were prepared by controlled thermal calcination and characterized using various techniques like XRD, FTIR, Raman, SEM, and surface area BET analysis. Rietveld refinements verified the presence of the ZrO 2 monoclinic phase with the space group P 2 1 / c in all samples and a second orthorhombic MoO 3 phase with the space group Pnma. The average crystal size decreased from 44 to 40 nm. FTIR and Raman spectroscopy confirmed the successful preparation of ZrO 2 /MoO 3 nanocomposites. SEM analysis showed ZrO 2 particles and MoO 3 nanoparticles adhered to the ZrO 2 surface, potentially creating a rougher texture. The results confirmed the formation of ZrO 2 /MoO 3 nanocomposites with increasing MoO 3 content, leading to an increased surface area of 19–23 m2/g. The catalytic performance evaluation revealed that the sample containing 30 % MoO 3 (ZM3) exhibited the highest hydrogen generation rate of 18,451 mL/g. min at 30 °C. The calculated activation energy for ZM3 was 18.78 kJ/mol, suggesting efficient hydrogen generation at moderate temperatures. [ABSTRACT FROM AUTHOR]

With the acceleration of industrialization and the increasing prominence of environmental pollution problems, the emission of nitrogen oxides (NOx) in the atmosphere has become a global concern. These emissions are not only hazardous to human health, but also one of the main factors leading to acid rain, photochemical smog and global climate change. Therefore, the development and implementation of efficient denitrification technologies are an important issue for environmental protection. The present review focuses on the research progress of the denitrification technology in the recent years, including the traditional denitrification methods and common technologies. At the same time, the advantages, limitations and application prospects of each method are analyzed. The mechanisms, influencing factors, advantages and disadvantages of the denitrification catalysts are also discussed. In addition, the future research trends and potential challenges of denitrification technology are discussed. It is expected that this review will provide useful references for promoting the development and application of denitrification technology, which may help researchers to choose high‐performance and cost‐effective methods. [ABSTRACT FROM AUTHOR]

Tailoring and optimizing Pt-based catalysts for the hydrogen evolution reaction (HER) is crucial for efficient energy conversion and storage. Reducing the amount of Pt used in HER catalysts is of paramount importance to enhance their application potential. It is highly challenging to precisely tailor Pt-based catalysts with the desired composition, uniform size, and homogeneous distribution, all while maintaining high catalytic activity and stability. Herein, the reducibility of H x MoO 3 is meticulously controlled by the incorporated amount of H+ ions into MoO 3 , enabling the preparation of size-controllable Au nano-cores. Furthermore, a low-loading PtCo shell is constructed on the surface of the Au nano-cores to generate Au@PtCo core-shell heterostructures. The distinctive core-shell structure not only augments the utilization of the Pt atom but also facilitates the alteration of the electronic configuration in PtCo, thereby escalating the catalytic efficiency for HER. By utilizing the dual-active sites of PtCo shell, the overpotential is reduced to only 95 mV at a current density of 10 mA/cm2, accompanied by significant improvements in kinetics and enhanced stability. Furthermore, the presented method is universal and can be utilized to fabricate analogous Au@PtFe, Au@PtNi, and Au@PtCu catalysts. Tailored preparation of Pt-based catalysts using sacrificial template method is presented. H x MoO 3 exhibits controllable reducibility, making it an ideal template for size-controllable Au nanoparticle synthesis. These Au nanoparticles support PtCo dual catalytic sites, forming the Au@PtCo structure with exceptional catalytic activity and stability for alkaline HER. The method is also extendable to prepare Au@PtM (M = Fe, Ni, Cu, etc.) catalysts. [Display omitted] • H x MoO 3 exhibits controllable reducibility. • H x MoO 3 as a template for metal preparation. • Au@PtCo exhibits exceptional catalytic activity and stability for HER. [ABSTRACT FROM AUTHOR]

In this paper, a series of B doped Ni/MgAl 2 O 4 catalysts for hydrogen production via steam reforming of methane (SRM) were prepared, and their catalytic activities and stability were evaluated. The characterization of XRD, XPS, TPR, BET, TPO, and TEM revealed that the addition of B could promote Ni dispersion, which lead to the reduce of Ni particle size. 0.5 wt% B was incorporated into Ni/MgAl 2 O 4 would increase Ni particle dispersion rate from 11.2% to 14.8%, which caused Ni particle average size was decreased from 8.78 to 6.96 nm. At the same time, 0.5% B doped would increase the chemisorbed oxygen content of the catalyst, and more oxygen vacancies were formed. Thus, Ni particles sintering and carbon deposition during SRM was suppressed, and the catalytic activity and stability were promoted. Ni-B 0.5 /MgAl 2 O 4 could achieve 90.2% methane conversion rate and 85% H 2 yield under 700 °C with a WHSV of 36,000 mL·(gh)−1 during SRM process, and only a marginal reduction (2%) of methane conversion rate was observed after 48 h reaction. The total carbon content on the used Ni-B 0.5 /MgAl 2 O 4 catalyst was approximately 0.031 g c ∙g cat −1, which was three times lower than that of Ni/MgAl 2 O 4. However, the excess B doping into Ni/MgAl 2 O 4 had a negative effect on the catalytic activity and stability. • 0.5 wt% B was incorporated into Ni/MgAl 2 O 4 would increase Ni particle dispersion rate from 11.2% to 14.8%. • 0.5 wt% B was incorporated into Ni/MgAl 2 O 4 would decrease Ni particle average size from 8.78 to 6.96 nm. • 0.5 wt% B was incorporated into Ni/MgAl 2 O 4 would increase oxygen vacancies. • Ni-B 0.5 /MgAl 2 O 4 could achieve 90.2% methane conversion rate and 85% H 2 yield under 700 °C. • Methane conversion rate was only decreased by 2% after 48 h SMR. [ABSTRACT FROM AUTHOR]

Oil palm empty fruit bunch (OPEFB) is one of the potential feedstocks for production of bioethanol. Among the challenges in the conversion of lignocellulosic material to bioethanol is pretreatment. This study aims to determine the optimum conditions of OPEFB pretreatment by using microwaves and aluminum salt catalysts, i.e., AlK(SO4)2 and Al2(SO4)3, for the production of reducing sugars that could be further fermented to bioethanol. The addition of inorganic salts, such as aluminum salt catalysts, during microwave heating enables to improve the results of biomass pretreatment. The optimization was conducted using the one factor at a time (OFAT) method. In Step 1, the factor optimized was the temperature (180–200 °C), while in Step 2 and Step 3 the factors optimized were the heating time (2–10 min), and the amount of catalysts (100–400 µmol/g biomass). The effects of the pretreatment could be seen clearly by the RSY obtained after enzymatic saccharification, based on the weight of pretreated OPEFB, with higher results on the OPEFB pretreated with microwave and AlK(SO4)2 or Al2(SO4)3 catalysts (55.08 or 55.75%, respectively) than those without the catalysts (38.32 or 38.36%, respectively). The total reducing sugar yield (RSY) from pretreatment hydrolysate and enzymatic saccharification was determined and used as a parameter in the optimization. The characteristics of pretreated OPEFB at optimum conditions were also compared with those of untreated OPEFB. Optimum conditions of OPEFB pretreatment by microwave heating with AlK(SO4)2 catalyst were 200 °C, 6 min, with 300 µmol catalyst/g biomass, whereas those with Al2(SO4)3 catalyst were 180 °C, 6 min, with 200 µmol catalyst/g biomass. At these conditions, the RSY reached 61.7 and 58.1% based on the initial biomass, respectively. [ABSTRACT FROM AUTHOR]

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The generation of solar H 2 emerges as a promising avenue for leveraging solar energy, contributing to mitigating climate change and restricting fossil fuel combustion. The advancement of the hydrogen economy significantly pivots on the production of hydrogen as a fundamental cornerstone. This article furnishes an overview of the available water-splitting technologies for harnessing solar energy as the primary source for hydrogen production, emphasizing the significant solar-to-hydrogen (STH) conversion efficiency. Photocatalytic water splitting, Photoelectrochemical water splitting, and Photovoltaic electrochemical water splitting have been thoroughly addressed over the past five-year period. A comprehensive assessment involves the evaluation and scrutiny of these solar technologies, acknowledging their commercial viability by analyzing key indicators like STH efficiency, robustness, economic likelihood, ecological sustainability, and other innovative attributes. [Display omitted] • Hydrogen economy is hailed as a pioneering element in sprouting a low-carbon future. • Solar hydrogen produced via water electrolysis is a reliable fossil fuel alternate. • Three core technologies delineate water splitting with distinct innovative features. • Elaborated on their advancements over the last five years extensively. • Each technology is methodically discussed highlighting their respective attributes. [ABSTRACT FROM AUTHOR]

Water electrolysis is one of the most promising green hydrogen production technologies. However, using precious metal materials as electrodes for these electrolyzers incurs high costs. To address these challenges and simultaneously retain the catalytic activity of precious metals, we synthesize a low-iridium catalyst, Nd–IrO 2. At 10 and -10 mA/cm2, this catalyst exhibits 233 and 36 mV overpotentials. Nd – IrO 2 maintains stability over prolonged operation in acidic environments, as evidenced by its consistent overpotential. Advanced calculations using density functional theory (DFT) have demonstrated that incorporating Nd and an ample amount of oxygen vacancies can modulate the d-band center of Ir and reduce the adsorption energy of electrochemical reaction intermediates. In summary, we present the synthesis of a low-iridium catalyst, which provides valuable insights for the design and development of catalysts with improved electrocatalytic performance. • Simple and efficient hydrothermal reaction combined with low temperature annealing. • Abundant oxygen vacancy improves electrochemical performance. • Reduce precious metal costs and improve electrocatalytic performance. [ABSTRACT FROM AUTHOR]

Objective In the sulfuric acid alkylation unit, the main causes and solutions to the deactivation of the hydrogenation catalyst were found by analyzing the running status of the selective hydrogenation reactor of 1,3-butadiene. Methods By analyzing the feedstock properties before and after catalyst deactivation, the effect of feedstock properties changes on the 1,3-butadiene removal rate was investigated. Results For the selective hydrogenation of the 1,3-butadiene catalyst, a high level of pH, caustic sodium and total sulfur contents in feedstock will inhibit the active centers of the catalyst. Conclusion The harmful impurities in feedstock were removed by optimizing operation. Additionally, the deactivated catalysts were re-activated by on-line treatment with pure hydrogen, the catalyst activity was significantly restored and maintained long-cycle running after re-starting up. [ABSTRACT FROM AUTHOR]

Borophene has been theoretically shown as an active catalyst for hydrogen evolution reaction (HER). However, there are a few experimental studies assessing the HER activity of borophene. Herein, we study for the first time HER activity of electrochemically exfoliated borophene in acidic medium. Borophene sheets obtained by anodic exfoliation of crystalline boron particles in Na2SO4 have β-rhombohedral crystal structure with an oxidized surface. Borophene exhibits notably higher catalytic activity compared to bulk boron with an overpotential of 480 mV at 10 mA cm−2 and a Tafel slope of 163 mV dec−1. The superior activity of borophene is attributed to enhanced HER kinetics as well as increased electrochemical surface area. Our study provides encouraging results for the use of borophene in catalysis applications. [ABSTRACT FROM AUTHOR]

In this study, the plant biomass from the phytoremediation was recovered, prepared, and investigated catalytic ability for the α-pinene isomerization. The results show that the Fe_loaded AAL biochar can catalyze the isomerization of a-pinene, with the α-pinene conversion of 90.5 % and the selectivities for monocyclic terpenes (limonene, terpinolene and γ-terpinene) of 57.1 %, bicyclic terpene (camphene) of 24.6 %. Iron in the plant biomass from phytoremediation is considered a decisive factor that heightened the conversion of α-pinene and the yield of isomers. This research has initially opened up a new application for the plant biomass absorbing heavy metal from the phytoremediation stage to resolve contaminants efficiently. [ABSTRACT FROM AUTHOR]

A dense electrode with high sulfur loading is a straightforward approach to increasing the energy density of lithium–sulfur battery (LSB), but the development of dense electrodes suffers from both fabrication challenges and electron/ion transport limitations. In addition, the shuttle effect of soluble lithium polysulfides and sluggish reaction kinetics cause declined utilization efficiency of the active material and poor cycling stability. Herein, a dense intercalation‐conversion hybrid cathode is prepared using MXene‐driven TiS2 nano‐needles decorated with TiO2 nanoparticles. The TiO2/TiS2 heterostructure simultaneously possessing a high adsorption capability (TiO2) and bidirectional electrocatalytic effect (TiS2) is observed to effectively suppress lithium polysulfide shuttling and facilitate the sulfur conversion reactions. Furthermore, it is believed that TiS2 provides additional capacity from the intercalation reaction and functions as a multichannel network to feed both Li+/e− to the active sulfur material due to its high electronic and ionic conductivities. Thanks to these synergistic effects, the LSB assembled using the TiO2/TiS2 heterostructure exhibits high gravimetric and volumetric energy densities of 331 Wh kg−1 and 730 Wh L−1, respectively, as well as superior cyclability at a high sulfur mass loading of 7.5 mg cm−2 and lean electrolyte of 2.5 μL mg−1. [ABSTRACT FROM AUTHOR]

Hydrogenation of CO2 represents a promising pathway for converting it into valuable hydrocarbons and clean fuels like dimethyl ether (DME). Despite significant research, several challenges persist, including a limited understanding of reaction mechanisms, thermodynamics, the necessity for catalyst design to enhance DME selectivity, and issues related to catalyst deactivation. The paper provides a comprehensive overview of recent studies from 2012 to 2023, covering various aspects of CO2 hydrogenation to methanol and DME. This review primarily focuses on advancing the development of efficient, selective, and stable innovative catalysts for this purpose. Recent investigations that have extensively explored heterogeneous catalysts for CO2 hydrogenation were summarized. A notable focus is on Cu-based catalysts modified with promoters such as Zn, Zr, Fe, etc. Additionally, this context delves into thermodynamic considerations, the impact of reaction variables, reaction mechanisms, reactor configurations, and recent technological advancements, such as 3D-printed catalysts. Furthermore, the paper examines the influence of different parameters on catalyst deactivation. The review offers insights into direct CO2 hydrogenation to DME and proposes paths for future investigation, aiming to address current challenges and advance the field. [ABSTRACT FROM AUTHOR]

To mitigate the greenhouse effect and environmental pollution caused by the consumption of fossil fuels, recent research has focused on developing renewable energy sources and new high-efficiency, environmentally friendly energy storage technologies. Among these, Li–CO2 batteries have shown great potential due to their high energy density, long discharge plateau, and environmental friendliness, offering a promising solution for achieving carbon neutrality while advancing energy storage devices. However, the slow kinetics of the CO2 reduction reaction and the accumulation of Li2CO3 discharge on the cathode surface lead to a significant reduction in space and active sites. This in turn results in high discharge overpotential, low energy efficiency, and low power density. This study elucidates the charge–discharge reaction mechanisms of lithium–carbon dioxide batteries and systematically analyzes their reaction products. It also summarizes the latest research advancements in cathode materials for these batteries. Furthermore, it proposes future directions and efforts for the development of Li–CO2 batteries. [ABSTRACT FROM AUTHOR]

The traditional high-temperature preparation process of polyimide can cause many problems and limits the wider application in extreme conditions. An important challenge to be solved urgently is the reduction of imidization temperature. In this work, twelve kinds of polyimide films with different chain rigidity were prepared at low temperature of 200 °C, in the absence or presence of imidazole used as the catalyst. The molecular rigidity and free volume were theoretically calculated, and relationship between structure and properties were systematically studied. The results show that imidization reaction under low temperatures is significantly affected by the rigidity of molecular chains. The rigid structure of polyimide is not conducive to the low-temperature imidization, but this adverse effect can be eliminated by adding catalyst, resulting the notably increased imidization degree. The optical and thermal properties can be improved to a certain extent for the chemically catalyzed system, resulting in relatively higher heat resistance and thermal stability. While the mechanical performance could be determined by complicating factors, greatly different from polyimide films prepared by high temperature method. To investigate aggregation structures of films, the effect of chain rigidity and catalyst on the stacking or orientation of molecular chains was further elaborated. This work can contribute to the understanding of chemically catalyzed imidization that is rarely reported in the existing research, and will provide guidance for the low-temperature preparation of high-performance polyimides. [ABSTRACT FROM AUTHOR]

This study aims to investigate the NOx/CO reduction characteristics of harmful gases according to the loading amount of active Ag, which plays the most important role in H2-SCR, and the type of support. H2-SCR with Ag loaded on support of TiO2 was reduced to Ag+ at about 140 °C in AgO oxide, and H2-SCR with Ag loaded on support of Al2O3 was reduced to Ag clusters (Agnδ+) at about 260 °C in AgO oxide. Because it is more unstable than AgO oxide, it promoted the chemical reaction of Ag. 0.5Ag/TiO2 H2-SCR showed the highest NOx conversion rate of about 18% at 200 °C, and the window width was also widened. 2Ag/Al2O3 H2-SCR improved the low-temperature activity of the catalyst due to its large specific surface area and the loading amount of active catalyst Ag. Although the harmful gas reduction performance has decreased significantly compared to the active material Pt used in the H2-SCR, research on active materials considering the performance the improvement and economic feasibility must be continued. [ABSTRACT FROM AUTHOR]

The novel flower shaped nanomaterials, known as Nanoflowers (NFs), have attracted the interest of the scientific community around the world with their unique morphology, ease of synthesis, large surface-to-volume ratio, and high electron conductivity, making them a promising nanomaterial for various relevant applications. Bimetallic NFs comprise of two different metallic elements, with superior properties due to the synergistic effect between the hereditary properties of the constituent metal atoms. Bimetallic NFs can be synthesized through various methods, each offering unique advantages. Conventional methods provide a traditional approach to NF synthesis, while electrodeposition methods offer precise control over NF morphology and composition. Biological methods harness the power of biological systems for green and sustainable NF synthesis. Various characterization techniques for identifying the morphology of NFs include HR-TEM, SEM, EDX, XRD etc. These NFs exhibit exemplary catalytic activity with high selectivity and catalytic yield due to their large surface areas and augmented active site density. This review delineates the synthesis, morphology, electronic properties and catalytic applications of bimetallic NFs. The manuscript depicts various catalytic reactions and focuses on mechanism and role of bimetallic NFs in these reactions. Moreover, the recent challenges and future prospects of these bimetallic NFs are well discussed in detail. [ABSTRACT FROM AUTHOR]

NiO nanoparticles were synthesized from pine cone extract by green synthesis method, which is a simple, cost-effective, environmentally friendly and sustainable method. The particle size of NiO nanoparticles was determined to be in the range of 10–25 nm by X-diffraction differential and transmission electron microscope analysis, and the bandgap energy of NiO nanoparticles was determined to be 2.66 eV. The catalytic effect of NiO nanoparticles in both microwave-assisted sodium borohydride hydrolysis and photocatalytic reduction of methylene blue was examined and it was determined that they had a high catalytic effect in both applications. It was determined that the hydrogen production rate in sodium borohydride hydrolysis was 1135 mL/g/min. The activation energy of sodium borohydride hydrolysis is 29.69 kJ/mol and 29.59 kJ/mol for the nth-order and Langmuir Hinshelwood kinetic models, respectively. In the photocatalytic reduction of methylene blue with NaBH4, it was determined that the reduction did not occur in the absence of a catalyst, but in the presence of the catalyst, the reduction occurred 98% in 3 min. It was determined that NiO nanoparticles were used five times in the photocatalytic reduction of methylene blue and the reduction efficiency for the fifth time was 93%. It was determined that the photocatalytic reduction of methylene blue was pseudo-first order and the rate constant was 1.63 s−1. It was determined that NiO nanoparticles synthesized by the environmentally friendly green synthesis method can be used as catalysts for two different applications. NiO nanoparticles were synthesized from pinecone extract in a simple, cost-effective, and green method. The synthesized NiO nanoparticles were characterized using various characterization techniques. NiO nanoparticles have high activity both in the photocatalytic reduction of methylene blue and in the hydrolysis of sodium borohydride, and they are catalysts with high activity in two different applications. Photocatalytic reduction of methylene blue with uncatalyzed NaBH4 was not achieved and was completed in 3 min in the presence of NiO nanoparticle catalyst. It was determined that the hydrogen production rate in sodium borohydride hydrolysis was 1135 mL/g/min. NiO nanoparticle catalysts have low activation energy for sodium borohydride hydrolysis. [ABSTRACT FROM AUTHOR]

MoS2-supported ceramic filler catalyst is prepared by dispersion-impregnation-sintering process. The phase structure, microstructure and element distribution of the catalyst are characterized and analyzed by XRD, SEM and EDS. The results showed that MoS2 is uniformly loaded on the surface of iron mud-based ceramic filler, and the rough surface structure of the catalyst would expose more active sites in the reaction. With CODcr removal rate as the evaluation index, the effects of pH, m (CODcr): m(H2O2), catalyst dosage and reaction time on heterogeneous Fenton treatment of papermaking wastewater by MoS2 supported ceramsite filler catalyst are investigated. The results showed that under the optimal conditions of pH 2.5, catalyst dosage 30 g/L,m(CODcr): m(H2O2)=1:1.5, reaction time 120 min, the CODcr removal rate of papermaking wastewater was 72.52%. The free radical quenching experiment showed that in the heterogeneous Fenton oxidation system, The active substances that degrade organic pollutants are mainly · OH,¹O2, ·O2-. [ABSTRACT FROM AUTHOR]