Since the previous fluidization and agglomeration models failed to describe the enhanced fluidization of ultrafine powders with the addition of microspheres, a novel energy balance model coupled with collision probabilities between agglomerates and Fe microspheres has been proposed to elucidate the intensification mechanism and to predict the agglomerate size. The intensification effects are mainly attributed to the spatial isolation and the collision effects between Fe microspheres and agglomerates. Furthermore, the calculated agglomerate sizes agree well with the experimental data. The model can provide a guidance for the addition of microspheres and the regulation of agglomerates in the fluidized bed.

Enhancing the stability of Pt single atoms (SAs) remains a critical bottleneck for practical applications. Herein, we overcome this limitation by developing a ZrCl3-CH4 system that enables an explosive nucleation to directly construct defect-rich ZrC nanoislands (NIs) on carbon cloth as ultrastable anchoring platforms for Pt single atoms (Pt1@ZrC NIs). This strategy dramatically enhances the surface number density of ZrC particles by 2 orders of magnitude over conventional methods and eliminates the long-standing issue of free carbon contamination. The Pt1@ZrC NI electrode exhibits a strong synergy, where ZrC promotes water adsorption/dissociation and Pt facilitates hydrogen migration/desorption, yielding a mass activity 116- and 132-fold greater than that of the commercial Pt@C catalyst in alkaline and acidic media, respectively. Moreover, owing to the excellent acid- and base-resistance of ZrC and its strong binding to Pt SAs and the substrate, the Pt1@ZrC NIs catalyst maintains exceptional stability in both acidic and alkaline media.

TiNCl has garnered extensive attention in fields such as superconductivity, catalysis, and energy storage due to its special two-dimensional layered structure and excellent electrical performance. However, the efficient synthesis of TiNCl still faces challenges because the conventional synthesis methods suffered from complex procedures, lengthy synthesis times, and the inevitable formation of byproducts, limiting its practical applications. Herein, a narrow temperature range was found to directly synthesize TiNCl, and a fluidized bed chemical vapor deposition (FBCVD) process was developed to efficiently synthesize TiNCl, significantly simplifying the process and reducing the synthesis time from several weeks to about 30 min. The synthesis yield of the FBCVD process is 3529 times that of the precursor conversion method. Moreover, the separation method, degradation behavior, and strategies for inhibiting the degradation of TiNCl were systematically investigated. These results provide a pathway for taking TiNCl from the laboratory to practical applications.

Lithium-sulfur (Li-S) batteries is severely hindered by polysulfide shuttling and sluggish redox kinetics, necessitating advanced cathode designs that simultaneously achieve efficient polysulfide catalysis and electron transfer. Here, we present a europium tungstate/metallic tungsten (EuWO4/W) heterostructure catalyst synthesized via controlled hydrogen reduction of Eu2(WO4)3. This strategy leverages the stable Eu2+ 4f7 configuration for structural integrity and forms highly conductive W0 from W6+ precursors to enhance electron transport and molecular activation by the distinct redox contrast (W6+/W0) across EuWO4/W interfaces. The resultant EuWO4/W cathode delivers exceptional electrochemical performance, achieving an initial discharge capacity of 1535.2 mAh g-1 at 0.1C and retaining 659.7 mAh g-1 after 1000 cycles at 2C (0.029% decay per cycle). In situ spectroscopy and theoretical calculations reveal the distinct yet complementary catalytic roles within the heterostructure. High-valence W6+ in EuWO4 acts as a strong Lewis acid to provide vacant orbitals for polysulfide anchoring, whereas low-valence W0 donates electrons into antibonding orbitals to accelerate S-S bond rupture. Coupled with rapid charge transport, these synergistic interactions establish a dual activation mechanism inaccessible to conventional single-phase catalysts. This work thus introduces a heterovalent-W-engineered interface as a powerful paradigm for designing multifunctional catalysts that unlock fast and efficient poly sulfide conversion in Li-S batteries.

Enhancing the stability of Pt single atoms (SAs) remains a critical bottleneck for practical applications. Herein, we overcome this limitation by developing a ZrCl3-CH4 system that enables an explosive nucleation to directly construct defect-rich ZrC nanoislands (NIs) on carbon cloth as ultrastable anchoring platforms for Pt single atoms (Pt1@ZrC NIs). This strategy dramatically enhances the surface number density of ZrC particles by 2 orders of magnitude over conventional methods and eliminates the long-standing issue of free carbon contamination. The Pt1@ZrC NI electrode exhibits a strong synergy, where ZrC promotes water adsorption/dissociation and Pt facilitates hydrogen migration/desorption, yielding a mass activity 116- and 132-fold greater than that of the commercial Pt@C catalyst in alkaline and acidic media, respectively. Moreover, owing to the excellent acid- and base-resistance of ZrC and its strong binding to Pt SAs and the substrate, the Pt1@ZrC NIs catalyst maintains exceptional stability in both acidic and alkaline media.

Ultra-high temperature thermal energy storage (UHT-TES) technology offers an important pathway to address the decarbonization needs of critical resource industries. Herein, we provide a perspective on the principles behind various UHT-TES technologies including high-temperature melts, solid ceramic composites, and particles. An overview of their key mechanisms and commercialization status is provided. Achievements have been made at the laboratory scale such as over 40% thermal-to-electricity conversion using thermal photovoltaics and approximately 60% using gas turbine combined cycle power generation. However, challenges during deployment include lack of long-cycle demonstration to verify the stability of brick-based materials, defluidization of particle materials, and efficient heat exchange systems under ultra-high temperatures. As such, future research should focus on solving these challenges by developing efficient and durable systems to extract the stored high-grade heat, and integrating UHT-TES with existing critical resource infrastructure at scale.

This study addresses the issue of increased energy consumption caused by bubble adhesion during the oxygen evolution reaction in electrochemical ironmaking anodes. By constructing a femtosecond laser-processed micro-nano porous array structure on the anode surface, rapid and spontaneous bubble detachment was achieved. The wetting characteristics, bubble behavior, and electrochemical performance of electrodes with different structures were systematically investigated. Results show that a microporous array with a pore size of 50 μm optimally balances bubble nucleation density, detachment behavior, and active surface coverage. The electrode achieves an OER potential of 1.24 V at 50 mA·cm-2, which is 9% (120 mV) lower than that of conventional dimensionally stable anodes, along with shorter bubble detachment time and excellent potential stability. Furthermore, multiphysics modeling confirms that the beneficial micro-convection generated during periodic bubble detachment enhances the limiting current density of mass transfer. This work provides new insights and a theoretical foundation for the development of efficient, low-energy green electrochemical ironmaking technologies.

The gas-based direct reduction process offers considerable advantages for the low-carbon metallurgy and the comprehensive utilization of complex polymetallic mineral resources. In the industrial background of efficiently utilizing titanomagnetite resources and reducing carbon emissions via CH4-CO2 reforming, this study investigated the self-reforming behavior of pre-oxidized-reduced titanomagnetite. Significant progress was achieved in enhancing conversion efficiency of CH4-CO2 reforming by controlling the distribution of reduced iron, employing an effective gas-solid contact fluidization technique. The results demonstrate that pre-oxidation treatment promotes the formation of a hematite layer on the particle surface of titanomagnetite, which subsequently enables the reduction of the particle surface to be enveloped in metallic iron. Compared to direct-reduced ore, the proportion of active sites on the particle surface is increased by 35%. Furthermore, the CO2 conversion rate and the reduction potential of the reforming product gas for pre-oxidized-reduced ore are improved by 14.9% and 13.3%, respectively, thereby achieving highly efficient CH4-CO2 self-reforming of reduced titanomagnetite. When the mol(CH4:CO2) >= 2.5 and the reforming temperature >= 950 degrees C, the reduction potential of the reforming product gas can exceed 97%, and the metallization degree further increases after reforming. Additionally, the mechanism by which pre-oxidation treatment enhances the CH4-CO2 self-reforming behavior of reduced titanomagnetite was established. The findings, together with the pre-oxidation enhancement method, provide a scientific basis for the development of the self-reforming of methane within the low-carbon metallurgy process of titanomagnetite.

Aqueous Zn-ion batteries (AZIBs) are promising candidates for large-scale energy storage owing to their intrinsic safety and low cost. However, their practical deployment is severely hindered by Zn anode instability arising from parasitic H2 evolution, interfacial corrosion, dendrite growth, and by-product accumulation. Herein, we propose a low-cost yet multifunctional electrolyte additive, triethylenetetraminehexaacetic acid (TTHA), to regulate Zn ion solvation chemistry and interfacial deposition behavior. In situ/ex situ characterizations combined with theoretical simulations reveal that TTHA partially replaces coordinated H2O in the Zn2+ solvation sheath, suppressing H2O activity and mitigating H2 evolution. Meanwhile, TTHA adsorbs preferentially on the Zn surface, homogenizing interfacial charge distribution, and promoting preferential Zn (002) plane growth. Importantly, TTHA establishes a buffered interfacial environment that effectively retards local alkalization during cycling, thereby inhibiting interfacial corrosion and the formation of basic zinc sulfate. Benefiting from these synergistic effects, Zn||Zn symmetric cells exhibit an ultralong cycling lifespan exceeding 6000 h at 1 mA & centerdot;cm-2, while Zn||V2O5 full cells retain 89.2% of their initial capacity after 1000 cycles at 1 A & centerdot;g-1 and deliver improved rate capability and Coulombic efficiency. This work demonstrates a simple yet highly effective electrolyte engineering strategy and provides new mechanistic insights and a practical pathway toward durable, high-performance AZIBs.

Lithium-sulfur (Li & horbar;S) batteries are hindered by lithium polysulfide (LiPS) shuttling and sluggish redox kinetics, demanding catalysts that both anchor LiPS and accelerate their conversion. Here, we introduce anion-tailored asymmetry engineering of MoS2 via controlled Se and Te substitution. The intrinsic size mismatch of S/Se/Te induces lattice and electronic asymmetry, weakening in-plane covalent bonds and creating localized electronic states. In addition, the dual effects lead to more exposure of additional edge sites and activates inert basal planes, enabling concurrent catalytic activity. Consequently, the optimized MoS1.75Te0.25-S cathode delivers an initial capacity of 1486.2 mAh g-1 (0.1 C) and 537.6 mAh g-1 (1.0 C) after 3000 cycles and 382.9 mAh g-1 after 3000 cycles at 3.0 C, indicating an ultralow decay rate of 0.012% per cycle. Even at a high sulfur loading, it sustains robust capacity retention, underscoring strong practical promise. These results establish anion-tailored asymmetry engineering as a generalizable strategy, providing mechanistic insights and design principles for advanced Li & horbar;S batteries.

Electrochemical ironmaking represents one of the key technological pathways for achieving a low-carbon transition in the steel industry. However, bubble attachment at electrode interfaces causes mass transfer limitations and increased energy consumption, which severely hinder its industrial application. To address this challenge, this study focuses on ultrasound-assisted electrochemical deposition of iron, employing a combination of electrochemical testing, in-situ interfacial observation, and multi-scale characterization to systematically investigate the effects of different ultrasonic power levels (0-60 W) on macroscopic performance, gas evolution behavior at interfaces, electrochemical kinetics, nucleation mechanisms, and microstructural evolution during the iron electrodeposition process. The results demonstrate that 20 W ultrasound significantly reduces cathodic hydrogen bubble detachment size, enhances bubble detachment frequency from both anode and cathode, decreases charge transfer resistance by 52.40%, and transforms the nucleation mode from progressive to instantaneous, achieving energy consumption reductions of 15.54% and 28.34% in standard and depleted Fe2+ electrolyte systems, respectively. Moderate ultrasonic power (10-20 W) promotes grain refinement, hardness improvement, and significant reduction in surface roughness, whereas excessive power (≥40 W) leads to grain coarsening and performance degradation. This study establishes 20 W as the optimal process window balancing energy efficiency, deposition rate, and coating quality, revealing the “optimization-transformation” regulatory mechanism of the ultrasound on iron electrochemical deposition. These findings provide theoretical foundations and technical guidance for developing green and efficient electrochemical iron smelting technologies.

Titanium nitride (TiN) is a versatile ceramic material renowned for its high hardness, excellent electrical conductivity, and plasmonic effects, yet its performance is highly dependent on its stoichiometry (x in TiNx). The synthesis of near-stoichiometric TiN powder (0.98 <= x <= 1.01), which exhibits optimal properties, remains challenging due to a mismatch between mass transfer and reaction kinetics. Herein, we developed a novel fluidized-bed process involving the controlled formation and subsequent dechlorination of a stoichiometric TiNCl coating on seed particles, achieving a final stoichiometry of x = 0.99. The introduction of NH3 was identified as a critical step for effectively reducing residual chlorine impurity. Furthermore, a self-exfoliation mechanism during the transformation from TiNCl to TiN was revealed. This precursor stoichiometry locking strategy, combined with a fluidized-bed process, not only achieves a 161-fold improvement in dechlorination efficiency over the fixed-bed system but also exhibits a high synthesis rate (similar to 13 g h-1 in a 30 mm-diameter reactor), demonstrating great promise for the scalable production of near-stoichiometric TiN powder.

ABSTRACT MXenes are a class of high‐performance materials receiving significant attention in areas such as energy and sensors. However, their conventional synthesis via defective etching raises environmental concerns due to the heavy use of hazardous chemicals. Herein, the environmental impacts of emerging MXene synthesis pathways are systematically evaluated from lab to process scales. Transforming away from solvent‐based etching could enable a 94% reduction in carbon emissions with improved reactant efficiency and recovery. Further, process optimization opportunities are identified for gas‐phase and molten salt synthesis pathways to achieving 67% to 85% reduction in human health, ecosystems, and natural resource impacts. Future research should target developing processes with dispersant to product ratio reaching 5.3 L/kg, which can reduce the carbon emission of MXene production down to 27 kg CO2‐eq/kg, making it one of the leading advanced nanomaterials.

The influence of glass bead microspheres addition ratios on the fluidization enhancement reduction of ultrafine CuO in a fluidized bed reactor is investigated. The mixed particles show robust fluidization under hot state without reaction when the mass ratio of glass bead microsphere to CuO (R) is exceeding a critical value of 4, while it is divided into two R ranges that suitable for robust fluidization by the reduction with H2, indicating the two distinct fluidization strengthening mechanisms: self-agglomeration fluidization and core-shell structure fluidization. The range of R for self-agglomeration fluidization and core-shell structure fluidization both can be effectively expanded by reducing the H2 volume fraction and by decreasing the reaction temperature. This work contributes to the theory of particle-assisted fluidization enhancement in the reaction of ultrafine powders.

The iron and steel industry is among the top three sources of industrial carbon dioxide(CO2)emissions,with over 70％of its greenhouse gas emissions directly attributed to the use of coal and coke as fuel and reducing agents.To mitigate greenhouse gas emissions and achieve sustainable development,the advancement of decarbonization technologies is crucial.Electrolytic ironmaking powered by renewable electricity offers the potential to entirely eliminate CO2 emissions,laying the foundation for zero-carbon iron production.This review systematically summarizes the current status of electrolytic ironmaking technologies,covering advancements from molten salt electrolysis to aqueous electrolysis.It critically analyzes the challenges and issues associated with different technological pathways and evaluates their levels of technological maturity.Finally,the economic viability and technical challenges of electrolytic ironmaking are discussed to provide an outlook on its development prospects.As a frontier technology for promoting green and low-carbon transformation in the iron and steel industry,electrolytic ironmaking offers a promising complementary approach to achieving industrial decarbonization.

The heterogeneous structure is considered to improve the theoretical prediction of gas-solid hydrodynamics in pressurized bubbling fluidized beds. The two-fluid simulation shows that the traditional unmodified Gidaspow model overestimates the gas-solid coefficient and bed expansion. As a comparison, the simulations which consider the meso-scale structures predict the reduced gas-solid drag coefficients and the reasonable bed expansions especially at high superficial gas velocities. The decrease in the dimensionless gas-solid drag coefficient with the elevated pressure indicates that the drag modification based on the heterogeneous structure is essential. The parameter sensitivity analysis demonstrates that the effect of the elevated pressure on the gas-solid drag force should be mainly attributed to the changes in minimum fluidization velocity, while the bubble behaviors contribute slightly. Moreover, the gas-solid slip velocity shows a surprisingly uniform distribution, which verifies the dynamic steady state of gas-solid interaction in bubbling fluidized beds.

Titanium nitride (TiN) is a typical transition metal nitride known for its excellent physical and chemical properties, attracting extensive interest in mechanical, electronic, biological, and catalytic applications. The stoichiometry, particle size, and impurity content of TiN powders are critical factors influencing material performance. High-quality TiN powders typically require small particle sizes, low impurity levels, and near-stoichiometric compositions. Nevertheless, current synthesis methods often struggle with mismatched mass transfer and reaction processes, posing challenges to the production of high-quality TiN powders. Herein, the quality of TiN powders produced by solid-phase, liquid-phase, and gas-phase synthesis methods are reviewed from the perspective of the reaction system. We explore the critical obstacles to achieving high-quality TiN powders and outline recent strategies aimed at improving mass and heat transfer, alongside optimizing reaction pathways. Finally, insights into the developmental trends in TiN powder are presented.

The steel industry, a critical pillar of global economic development, is highly energy-intensive, accounting for approximately 7%–9% of global energy-related CO 2 emissions. The transition from traditional carbon-intensive metallurgy to hydrogen-based metallurgy represents a pivotal pathway for the green and sustainable development of the steel industry. This review elaborates on the evolution of hydrogen direct reduction technologies, highlighting early pilot- and commercial-scale plants that primarily utilized fluidized bed reactors with natural gas reforming or ammonia plant exhaust gases as reducing agents. These early efforts demonstrated the feasibility of hydrogen reduction but could not achieve long-term stable operation. The urgent need for decarbonization has resulted in renewed focus on research and development in hydrogen direct reduction, with steel companies proposing diverse technological solutions and advancing industrial demonstrations globally. Despite significant progress, the cost of hydrogen production has become a significant barrier to its widespread adoption. Strategies to lower costs include enhancing the reaction efficiency, integrating green electricity to supply heat, utilizing low-grade ores, and leveraging renewable, off-peak, and surplus electricity for hydrogen production. As the price of hydrogen is 0.7 ¥·Nm −3 (Standard volume), the cost of the hydrogen direct reduction–electric arc furnace process is comparable to that of the blast furnace–basic oxygen furnace process. Hydrogen direct reduction is expected to gradually replace the conventional blast furnace ironmaking method, which is emerging as a mainstream steel production process that underpins the green, low-carbon, and sustainable development of the global steel industry.

Photocatalytic non-oxidative coupling of methane (PNOCM) provides a green and sustainable route to the synthesis of ethylene (C2H4). TiO2 intrinsically can activate CH4 through photogenerated holes. However, taking advantage of this property for highly selective C2H4 production remains a significant challenge. Herein, CuO nanoparticles loaded hollow cubic TiO2 (CuO@hcTiO(2)) nanoparticles are synthesized via hydrolytic-crystallization constrained morphology engineering combined with a chemical precipitation method. It exhibited an outstanding C2H4 selectivity of 97.7% and a production efficiency of 3937.2 mu mol g(CuO)(-1) h(-1), with excellent stability reaching 30 h. Compared with reported TiO2 based photocatalysts, the selectivity of C2H4 from CuO@TiO2 increased by 2 similar to 20 fold. Mechanistic investigations suggest that CuO nanoparticles loaded on TiO2 act as active sites for *CH3 capture due to the partially filled d orbitals. And the type-I heterojunction between CuO and TiO2 promotes photogenerated holes migration from TiO2 to the CuO, facilitating the dehydrogenation of adsorbed *CH3 to *CH2 and subsequent coupling to C2H4. This work provides a promising strategy for designing photocatalysts to efficiently synthesis C2H4 via PNOCM.

The reduction behavior of iron ore is the fundamental process in ferrous metallurgy. Considering the gas-solid interface-structure relationship, heterogeneous transfer-reaction behavior, and multiple reaction kinetics, this work provides an effective analytical tool to investigate the fluidized reduction of iron ore. The conical fluidized bed is numerically examined to be capable of preventing de-fluidization induced by the sticking behavior, due to the steady circulation of flow pattern and full fluidization of coarse agglomerates. Compared with the hydrogen concentration, the gas velocity shows a stronger influence on the agglomerate reduction rate for the more efficient gas-solid contact. For the simulated transitions of Fe2O3 2 O 3-* Fe3O4 3 O 4-* Fe (1-x) O-* Fe are assumed to overlap each other, there exist discrepancies between computed and theoretical reduction degrees. The experimental and numerical findings can be used to develop a methodology for optimizing the operational complexity and economic benefits of the fluidized reduction of iron ore.