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Synthesis of well dispersed and strongly interacted Ni-based catalysts benefits the catalytic performances in high-temperature reactions. Significant works have been reported on the roles of calcination environments. During calcination of the catalyst precursors (pretreatment or activation in other cases), the type of atmospheres greatly affects the size, metal-support interaction (MSI) and surface properties of Ni-based catalysts, influencing the catalytic performances. In this review, it is the first time to comprehensively summarize the influences of three categories of atmospheres – oxidative (air, O2 and CO2), inert (N2, Ar) and reductive (H2, NO, N2O and CO) gases, on the physiochemical properties of Ni-based catalysts, which provides a facile and general strategy to optimize the formation of metal nanoparticles on the supports.

Conversion of methanol to light olefins (MTO) using SAPO-34 molecular-sieve as the reaction catalyst was studied in a fluidized bed reactor within the temperature range of 400–550 °C by 50 °C increments and under 50, 66.6 and 90 vol% of methanol in the feed, diluted with water or an inert. SAPO-34-based catalyst was prepared by agglomeration with clay and alumina to allow proper fluidization. Catalytic results show the highest olefin yield for 500 °C and a reduction in catalyst deactivation for 1:1 methanol:water molar ration in the feed.

High-temperature pyrolysis technology can effectively solve the problem of municipal solid waste pollution. However, the pyrolysis gas contains a large amount of CO2, which would adversely affect the subsequent utilization. To address this problem, a novel method of co-precipitation modification with Ca, Mg and Zr metals was proposed to improve the CO2 capture performance. X-ray diffraction (XRD) patterns and energy dispersive X-ray spectroscopy analysis showed that the two inert supports MgO and CaZrO3 were uniformly distributed in the modified calcium-based sorbents. In addition, the XRD results indicated that CaZrO3 was produced by the reaction of ZrO2 and CaO at high temperatures. The effects of doping ratios, adsorption temperature, calcination temperature, CO2 concentration and calcination atmosphere on the adsorption capacity and cycle stability of the modified calcium-based sorbent were studied. The modified calcium-based sorbent achieved the best CO2 capture performance when the doping ratio was 10:1:1 with carbonation at 700 °C under 20% CO2/80% N2 atmosphere and calcination at 900 °C under 100% N2 atmosphere. After ten cycles, the average carbonation conversion rate of Ca-10 sorbent was 72%. Finally, the modified calcium-based sorbents successfully reduced the CO2 concentration of the pyrolysis gas from 37% to 5%.

Molybdenum disulfide (MoS2) with low cost, high activity and high earth abundance has been found to be a promising catalyst for the hydrogen evolution reaction (HER), but its catalytic activity is considerably limited due to its inert basal planes. Here, through the combination of theory and experiment, we propose that doping Ni in MoS2 as catalyst can make it have excellent catalytic activity in different reaction systems. In the EY/TEOA system, the maximum hydrogen production rate of EY/Ni-Mo-S is 2.72 times higher than that of pure EY, which confirms the strong hydrogen evolution activity of Ni-Mo-S nanosheets as catalysts. In the lactic acid and Na2S/Na2SO3 systems, when Ni-Mo-S is used as co-catalyst to compound with ZnIn2S4 (termed as Ni-Mo-S/ZnIn2S4), the maximum hydrogen evolution rates in the two systems are 5.28 and 2.33 times higher than those of pure ZnIn2S4, respectively. The difference in HER enhancement is because different systems lead to different sources of protons, thus affecting hydrogen evolution activity. Theoretically, we further demonstrate that the Ni-Mo-S nanosheets have a narrower band gap than MoS2, which is conducive to the rapid transfer of charge carriers and thus result in multi-photocatalytic reaction systems with excellent activity. The proposed atomic doping strategy provides a simple and promising approach for the design of photocatalysts with high activity and stability in multi-reaction systems.

The thermogravimetric (TGA) responses of PA6 composites filled with synthetic Graphite (G) and Graphite nanoplatelets (GNP) each on 5 cumulative loading levels were investigated using two processing streams each of a common processing strain. To determine the effect of the 2 carbon fillers on the thermal stability of unfilled PA6, the temperatures at which 5, 20 and 50 wt% losses occurred were observed for the composites and the unfilled PA6. Weight lost at 460 °C and the carbon char at 600 °C were also noted. Effects of varying extrusion screw speeds as well as sonication amplitudes with time were given cognisance. To evaluate the effect of processing on the thermal response of the composites, two in situ polymerised streams and 2 melt extrusion streams with each set being equivalent in ‘magnitude of strain histories’ were characterised using TGA. The TGA for the unfilled PA6 and its graphite composite were conducted under inert (N2) blanketing and reactive (air) media. Initially, TGA responses of the fillers were studied and both GNP and G remained stable in N2. The onset of weight loss under N2 blanketing for G and GNP were respectively 820 ± 27.6 °C and 777.3 ± 17.7 °C. At temperature close to 900 °C, G showed relatively poorer thermal stability compared to GNP. A residue of 1.3% for G and 2.0% for GNP were left. The thermal stability of the streams G200/3 and G100/6 remained within a close range thus indicating that varying screw speeds and durations did not play a significant role on influence the thermal stability of the melt processed composites. For the composites, thermal stability were comparable with unfilled PA6, especially in the melt-processed systems, while Some changes occurred in the 2 in situ polymerized systems (20/20 and 40/10) which was ascribed to the presence of small molecules from the catalysing species or unconverted monomers.

The inert sites of Prussian Blue Analogue (PBA) seriously affected its electrocatalytic activity and application, how to activate inert sites in PBA to fulfill effective oxygen evolution reduction (OER) is a major challenge. Herein, Mo substituted Fe sites and S doped in inert PBA were designed and synthesized by hydrothermal method to enhance structural stability and OER activity. PBA-SMo/NF shows the optimum activity with a low overpotential of 252 and 294 mV for harvesting current density 20 and 100 mA cm−2, respectively, and exhibits excellent durability under high current density. Theoretical calculation of H2O adsorption energy and Bader charges reveals that Mo sites in PBA-SMo possess favourable H2O adsorption kinetics. More important, Gibbs free energy diagram and DOS show PBA-SMo have lower energy barriers for OER and better conductivity. This work provides a kind of guidance for the design and optimization of PBA for broad applications.

Bismuth oxyhalides, BiOX (X = I, Br, and Cl), as a new class of promising catalysts for hydrogen evolution reaction (HER), have attracted growing interest from researchers. However, the active sites of BiOX are limited to the edges, leaving a large area of inert basal planes to HER. Herein, the activation of the inert basal planes of monolayer BiOX is explored by the first-principles calculations. It is found that the Gibbs free energies of hydrogen adsorption ( Δ G H 0 ) on halogen vacancies (VX, X = I, Br, and Cl) sites are close to the ideal value of 0 eV, indicating that the inert basal planes of BiOX can be activated by VX. With the increasing VX concentration, Δ G H 0 decreases and hydrogen is more strongly attached to VX sites. Moreover, the compressive strain can strengthen hydrogen adsorption on VX sites, whereas the opposite role is observed for the tensile strain. Hence, the highest HER of the basal planes can be achieved by the combinations of VX and strain. Furthermore, the resonant states of the Bi-p orbital of Bi atoms on VX sites are responsible for the flexible HER, which can be further determined according to the p-band center of Bi-p orbital. These results provide a comprehensive strategy to activate the inert basal plane and optimize the HER activity for two-dimensional (2D) catalyst.

Inert powders played an important role in the explosion inhibition of dust removal equipment and coal gasification process. In this paper, SiO2, dry water, carrageenan dry water, and NaHCO3 were adopted to explore the influences of inert powders on the deflagration flame propagation characteristics of mixed pulverized coal by a vertical pipeline. The results showed that the flame brightness of the mixed pulverized coal decreased with the irregularly discrete of flame front after the addition of inert powders. As the increasing of pulverized coal mesh number, the peak flame temperature first increased and then decreased, while the drop value of peak flame velocity and temperature increased with the increasing of mass concentration. In addition, the inerting rate affected the propagation of pulverized coal composite flame. When the inerting rate exceeded 1.0, the peak temperature drop increased rapidly and dry water exhibited the best inhibition performance.

In this research, curium oxide (CmO2) is studied as fuel for VVER-1200 reactor to get an attention to its energy value and possibilities. For this purpose, CmO2 is used in fuel rods or integrated burnable absorber (IBA) rods with and without UO2 and then compared with the conventional fuel assembly of VVER-1200 reactor. It is burned to 60 GWd/t by using SRAC-2006 code and JENDL-4.0 data library. From these studies, it is found that CmO2 is competent like UO2 as a fuel due to higher fission cross-section of 243Cm and 245Cm isotopes and neutron capture cross-section of 244Cm and 246Cm isotopes. As a result, when some or all of the UO2 of fuel rods or IBA rods are replaced by CmO2, we get a similar k-inf like the reference even with lower enrichment UO2 fuels. These studies show that the use of CmO2 as IBA rods is more effective than the fuel rods considering the initially loaded amount, power peaking factor (PPF), fuel temperature and void coefficient, and the quality of spent fuel. From a detailed study, 3% CmO2 with inert material ZrO2 in IBA rods are recommended for the VVER-1200 reactor assembly from the once through concept.

The responses of Al/PTFE reactive materials (RMs) under shock compression were investigated by a single-stage gas gun. A 3D mesoscale-model was established based on micro-computed tomography (micro-CT) slice images and confirmed with experimental results. In the high-pressure stage, the composites reacted partially, whereas there were no deviations between the partially reacted Hugoniot and the inert simulation results. The simulation reveals that the Teflon matrix melting on the high shock pressure. Melts and decomposition of the PTFE accelerated the diffusion of the atoms. Thus, the reactions of the Al/PTFE composites are more like a combustion rather than a detonation.

Fouling of a sweet crude oil derived from oil sands was studied in a re-circulation heating loop to identify causes of refinery preheater fouling. Oil was re-circulated for periods of up to 6 days through an electrically heated annular probe. The oil was maintained under gaseous atmospheres with air/nitrogen molar ratios from zero to 0.18, at total pressures of 460 kPa. The effects of wall and bulk temperature, flow velocity, dissolved oxygen content, and mineral particle additions on the fouling rate are reported.

Hybrid Reactive Distillation Configurations (HRDCs), with single feed/multi-side draws having both reactive and non-reactive sections, can be effectively used to get the desired selectivity in multi-reaction systems. Our previous research (Hasan et al., 2013a,b, 2014, 2015; Singh et al., 2018, 2019, 2021) was focused on finding designs of hybrid RD columns of desired selectivity for complex reaction schemes without inerts. In the present work, we extend the approach to cover a wider range of multi-reaction schemes and include systems with inerts present in feed as well as inert forming multi-azeotropes in the column. Using the concepts of attainable region and graphical simulation approach, we developed algorithms that are capable of finding at least one feasible design of hybrid RD configuration successfully that give the desired selectivity in the systems under study. Further, the effect of inert percentage in feed and volatility of inert on the design of hybrid RD columns is also investigated. The developed methodology allows us to find the maximum allowable percentage of inerts in feed to obtain a feasible design of hybrid RD column. The methodologies developed here are applicable to any number of inerts present in the feed, any number of total components, inerts of any volatility, inerts forming multi-azeotropes with any of the reactant, product/desired product. However, they are limited to single feed configurations and to the multi-reaction schemes with a maximum of three products undergoing further side reactions wherein the reactant(s) is/are of intermediate volatility.

Electrochemical CO2 reduction is a promising route to convert CO2 into the value added chemicals, and to control the increasing accumulation of CO2 in the atmosphere. The CO2 molecule is stable and chemically inert, so a highly efficient electrocatalyst is required for CO2 reduction. The single atoms with metal oxide support is a new frontier in CO2 reduction. The supported single atoms contain disperse isolated atoms with an appropriate support maximize the atom efficiency of metals for boosting the catalytic performance. In this review, we had discussed state-of-the-art research on the synthesis of single atoms supported on the metal oxide for boosting catalytic activity for CO2 reduction and special emphasis is placed on the influence of single atoms supported on metal oxide on the CO2 reduction. Furthermore, we had discussed the challenges, and opportunities for paving the development of single atoms with metal support and their application in electrocatalytic CO2 reduction.

Although 2H molybdenum disulfide (MoS2) layers are highly desirable for hydrogen evolution reaction (HER) owing to their high chemical stabilities and low cost, the inert basal plane and semiconducting nature severely hinder their practical applications. Here, the catalytic activities of 2H phase molybdenum-based compounds are unlocked via topological conversion reaction from Mo2GeC MAX phase to accordion-like molybdenum phosphosulphide. During the conversion reaction, phosphorus atoms can be implanted into the sandwich-like S-Mo-S planes and gradually substitute sulfur atoms, which are beneficial to optimize the electronic configuration and facilitate to absorb water molecules, unlocking the inert basal planes of 2H phase molybdenum-based compounds. The accordion-like molybdenum phosphosulphide exhibits high hydrogen production rates up to 288 mmol g−1 h−1 cm−2 at a high loading of 3 mg cm−2 and ultralong durability up to 35,000 cycles, satisfying the practical application for HER.

Noble gases are ideal natural tracers to characterize the storage, migration and origin of fluids in geological environments. They are chemically and biologically inert and therefore are only partially separated by physical processes including the one related to the molecular diffusion phenomenon, so called kinetic fractionation. However, its precise quantification is difficult to achieve and its modeling is still open for debates. Thus, in this work, we have investigated the capability of simple and predictive models to estimate elemental and isotopic fractionation of noble gases in various geological fluids. To do so, molecular dynamics simulations on noble gases in water, gas and oil under sub-surface conditions were performed. These numerical results were found to be consistent with previous ones including experiments and molecular simulations when available, i.e. in water. Interestingly, it appeared that the widely used square-root law is able to provide a good prediction for elemental fractionation between noble gases in all solvents, except for helium. Such unexpected result from the theoretical point of view is explained by a peculiar relationship between the molecular mass and the molecular size of noble gas elements. Regarding the noble gas isotopic fractionation, the square-root law is shown to be unable to provide reasonable results, confirming recent experimental and numerical works. As expected, it has been noticed that the kinetic theory relation provides a reasonable estimate of the isotopic fractionation in gas whereas it deteriorates in water and in oil. Finally, using the previous findings, we propose a simple and predictive scheme for the isotopic fractionation of noble gases in all studied geo-fluids which is noticeably better than both the square-root and the kinetic theory relations.

Radon exhalation from soil and ores is among the most dangerous risks for the public health care. The impact becomes even more powerful when technological enhanced naturally occurring radioactive materials (TENORM) are used for public and private building. Here, we built a down-scaled model (a 1.0 m × 1.0 m × 0.5 m parallelepiped) of a dwelling, whose construction materials contain TENORM harvested in a site in Crotone (Italy). We observed an increase of the radon activity in the model when TENORM residues are employed, reaching a value around 120 Bq/m3, i.e. up to three times higher than the typical values of Crotone indoor environment, which ranges around 40 Bq/m3. These results have then been compared to a real use case. The correspondence found between the values of radon activity concentration in the model and in the use case suggests that estimating the radon concentration is a useful method to target TENORM presence inside buildings.

Alumina oxide supported nickel (Ni/Al2O3) catalysts generally suffer from fast deactivation caused by coking and formation of nickel aluminate (NiAl2O4) in dry reforming of methane (DRM). Herein, for the first time, a self-stabilization mechanism of the Ni/Al2O3 catalyst (with 0.1 wt% Ni loading) was revealed and effectively applied for DRM. Namely, the conversion of catalytically active Ni species into catalytically inert NiAl2O4 spinel in DRM over the Ni/γ-Al2O3 catalyst could be mitigated by repeated reduction-reaction treatments owing to the increasing amount of Ni located on the NiAl2O4 isolation layer rather than the reactive γ-Al2O3. The self-stabilization could be achieved over Ni/α-Al2O3 as well, even with a faster rate, since the NiAl2O4 isolation layer can be directly formed in the first reduction-reaction cycle due to its small surface area and weak metal-support interaction. These observations not only highlight the importance of an isolation layer for protecting the catalyst from deactivation, but also provide a novel and efficient self-stabilization approach for catalytic DRM.

H4pypa is a nonadentate nonmacrocyclic chelator, which previously demonstrated high affinity for scandium-44, lutetium-177, and indium-111. Herein, we report the highly stable binary [Zr(pypa)] complex; the nonradioactive complex was synthesized and characterized in detail using high-resolution electrospray-ionization mass spectroscopy (HR-ESI-MS) and various nuclear magnetic resonance spectroscopies (NMR), which revealed C2v symmetry of the complex. The geometry of [Zr(pypa)] was further detailed via X-ray crystallography and compared with the structure of [Fe(Hpypa)]. Despite a slow complexation rate with an association half-life of 31.4 h at pH 2 and room temperature, the [Zr(pypa)] complex is thermodynamically stable (log KML = 38.92, pZr = 39.4). Radiochemical studies demonstrated quantitative radiolabeling achieved at 10 μM chelator concentration within 2 h at 40 °C and pH = 7, antibody-compatible conditions. Of the utmost importance, [89Zr][Zr(pypa)] is highly kinetically inert upon challenge with excess EDTA and DFO ligands, superior to [89Zr][Zr(DFO)]+, and maintains inertness toward human serum.

This work focuses on the systematic investigation of the shape, size, and composition-controlled synthesis of perovskite nanocrystals (NCs) under inert gas-free conditions and using pre-synthesized precursor stock solutions. In the case of CsPbBr3 NCs, we find that the lowering of reaction temperature from ∼175 to 100 °C initially leads to a change of morphology from bulk-like 3D nanocubes to 0D nanocubes with 3D-quantum confinement, while at temperatures below 100 °C the reaction yields 2D nanoplatelets (NPls) with 1D-quantum confinement. However, to our surprise, at higher temperatures (∼215 °C), the reaction yields CsPbBr3 hexapod NCs, which have been rarely reported. The synthesis is scalable, and their halide composition is tunable by simply using different combinations of precursor solutions. The versatility of the synthesis is demonstrated by applying it to relatively less explored shape-controlled synthesis of FAPbBr3 NCs. Despite the synthesis carried out in the air, both the inorganic and hybrid perovskite NCs exhibit nearly-narrow emission without applying any size-selective separation, and it is precisely tunable by controlling the reaction temperature. Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG Ministerio de Ciencia, Innovación y Universidades | Ref. RYC2018-026103-I Agencia Estatal de Investigación | Ref. PID2020-117371RA-I00 Xunta de Galicia | Ref. ED431F2021/05 Xunta de Galicia | Ref. ED431C2020/09 Ministerio de Economía, Industria y Competitividad | Ref. BES-2017-081670

The products of cement–asbestos treated in air at 1100°C were characterized by a multi-methodological approach to determine: (i) the effective deactivation of harmful asbestos fibers; (ii) the mineralogy and microstructure of the inert product and its possible use as a secondary raw material (SRM); and (iii) any potential health hazard of the SRM. For this purpose, energy-dispersive X-ray fluorescence spectrometry (EDXRF), X-ray powder diffraction (XRPD), scanning, and transmission electron microscopy (SEM and TEM) analyses were performed. The powdered SRM was also analyzed by dynamic laser scattering and solution leaching experiments, to determine grain size distribution and possible elements release. Our results confirm the deactivation of crocidolite and chrysotile asbestos fibers, but at the same time evidence a significant fraction of nanoparticles in the SRM and some critical releases of SO42–, F– and Cr6+ in solution. Both the nanoparticle fraction and the critical elemental release may pose human health concern and adversely affect potential applications of the SRM. Strategies to control the grain size distribution through adjusted thermal treatment conditions and microwave-assisted grinding operations are discussed. Possible routes to safely reuse the SRM are indicated.

Direct catalytic upgrading of biomass-derived fast pyrolysis vapors can occur in different process configurations, under either inert or hydrogen-containing atmospheres. This review summarizes the ...

Sapphire possesses chemically inert and high hardness. Therefore, it is difficult to get idea material removal rate (MRR) and low surface roughness through chemical mechanical polishing (CMP). Ultr...

Extraction of gold from the refractory gold ores is commonly practiced by cyanide leaching, which simultaneously generates a significant amount of hazardous cyanide tailings. The cyanide tailings, still bearing certain amounts of residual gold, subsequently go through chlorination roasting to further recover Au, Ag, and other nonferrous valuable metals, and consequently, rendering the tailings inert by forming a residue containing high concentrations of Fe. This study aims at recovering Fe from the pellet-form chlorination residue by carbothermic reduction, forming magnetic Fe3O4 or metallic Fe, followed by magnetic separation. The results show that by reduction roasting at 800 °C for 4 h, a maximum amount of Fe3O4 can be generated. However, the subsequent magnetic separation was poor due to the extremely fine particle sizes and complex mineralogical associations. Notably, carbothermic reduction at 1250 °C for 4 h resulted in the formation of a metallic Fe shell on the outer surface of each residue pellet. The magnetic separation resulted in the production of an Fe concentrate containing 82.17 wt% Fe with a total Fe recovery of 79.68 wt%.

Controlled ice nucleation offers several key benefits to the pharmaceutical lyophilization process, including reducing lyophilization cycle time, control of ice crystal morphology, and increased consistency of lyophilized product quality attributes. The rapid depressurization based controlled ice nucleation technique is one of the several demonstrated controlled ice nucleation technologies and relies on the rapid discharge of an inert pressurized gas to induce ice nucleation. In this work, a series of custom wireless gas pressure and temperature sensors were developed and applied to this process to better understand the mechanism of controlled ice nucleation by depressurization. The devices capture highly transient conditions both in the chamber near the vial and within the vial headspace throughout the entire process. The effects of ballast gas composition, initial charge pressure, and vial size on gas pressure and headspace/chamber temperature are explored individually. We model the depressurization as an isentropic process, allowing the influence of these parameters to be evaluated quantitatively. It is demonstrated that monatomic gases (e.g. argon) with low thermal conductivity produce the most favorable conditions for ice nucleation at the end of depressurization, based on temperature drop in the vial headspace. Experimental data also reveal a correlation between initial charge pressure and vial size with the temperature drop within the vial headspace, during depressurization. These findings ultimately provide deeper insight into the rapid depressurization based controlled ice nucleation process and help lay the foundation for a more robust process development and control.

The separation of CO2 from biogas to achieve vehicle/pipeline grade methane is an expensive step. Recently, PEI (polyethyleneimine) impregnated resins have been proposed and evaluated for CO2 separation from flue gases and air. However, its use in biogas upgrading and evaluation of the economic feasibility of such adsorbents have not been explored in detail. In this work, by modifying an inert polymeric resin (HP2MGL) using PEI, CO2 was separated from biogas. The sorbent exhibited the highest adsorption capacity of 2.7 mmolCO2/gads at 30% PEI loading, increasing to 2.9 mmolCO2/gads in the presence of moisture, and remained stable for up to five adsorption–desorption cycles. In situ DRIFTS studies showed that CO2 adsorption on PEI-impregnated sorbent is consistent with the zwitterion reaction mechanism, and the sorbent could be regenerated completely at 100 °C. The upgrading cost of biogas is primarily dominated by the operating cost of regeneration and the adsorbent cost. The economic feasibility analysis suggests that PEI-impregnated resin sorbent requires less capital and operating costs than conventional biogas upgrading technologies. Therefore, PEI-impregnated polymeric resins are promising for CO2 separation from biogas.