Bismuth-based materials have emerged as multifunctional components for zinc-based electrochemical energy storage systems, owing to their unique electronic structures, diverse crystal chemistry, high hydrogen-evolution overpotential, and favourable zinc affinity. In this review, we systematically summarize the recent progress in the design and application of bismuth-based materials for zinc-based electrochemical energy storage, including aqueous zinc-ion batteries (AZIBs), zinc-air batteries (ZABs), zinc-based flow batteries (ZFBs), and zinc-ion hybrid capacitors (ZIHCs). Specifically, we focus on various categories of bismuth-based materials‒metallic bismuth, bismuth oxides, chalcogenides, halides, oxyhalides, alloys, and heterostructures‒within the context of their crystal structures and corresponding electrochemical functionalities. A range of key factors are critically analysed, including synthesis methods, structural regulation, defect engineering, and reaction mechanisms, complemented by advanced in situ/operando characterization and density functional theory (DFT) calculations. The multifunctional roles of these materials are then featured across different device components‒anodes, cathodes, electrolytes, and interfaces‒covering their functions in zinc deposition regulation, charge storage, oxygen electrocatalysis, and side-reaction suppression. We conclude the review with a perspective highlighting the remaining challenges and future research directions, emphasizing the need for integrated multiscale design, scalable manufacturing, electrolyte co-optimization, and data-driven discovery to translate the intrinsic advantages of bismuth chemistry into practical high-performance zinc-based energy storage technologies.
Research on chemical recycling of waste plastics has expanded rapidly, yet industrial practice remains dominated by pyrolysis. Moving upcycling toward deployment requires integrated, in-depth analysis. Because polyolefins contain only carbon and hydrogen, this review focuses on reaction routes that convert them into high-value hydrocarbons: ethylene and propylene monomers, long-chain olefins, aromatics, linear alkanes, iso-alkanes and cycloalkanes. These products can displace petroleum-derived feedstocks. For each route, we summarize reaction pathways, catalyst structure–performance relationships, process-intensification strategies, and environmental and economic metrics, including life cycle assessment and techno-economic analysis. We also map how these factors interact. We highlight practical hurdles beyond catalytic activity, catalyst cost, shaping and attrition resistance, and heat and mass transfer limits with high-viscosity feeds. We stress that the resulting hydrocarbons must meet product specifications and gain market acceptance. A whole-process view is therefore essential. Beyond elegant catalytic chemistry, weak links in process engineering must be addressed. In the long term, we propose integrating artificial intelligence and renewable energy into polyolefin recycling factories to accelerate technological innovation and the deep integration of the industrial value chain. This comprehensive analysis identifies the main barriers to scale-up for each high-value pathway. It also offers guidance for applying similar strategies to other plastics and mixed plastic streams.
Conventional coal pyrolysis tends to drive aromatic condensation and graphitic stacking, which limits closed-pore formation and leads to sluggish Na+ transport, low plateau capacity and poor initial Coulombic efficiency (ICE) in coal-derived hard carbon. Here we develop a rapid temperature shock (RTS) strategy to redirect coal carbonization through a kinetically constrained thermal pathway. The rapid heating restrains graphitic rearrangement and secondary condensation, while promoting cross-linked disordered carbon reconstruction. The resulting RTS-HC exhibits an enlarged d002 spacing of 0.392 nm, abundant closed nanopores and a turbostratic carbon framework. These structural features lower the Na+ migration barrier to 0.38 eV and facilitate reversible low-potential Na storage. Density functional theory calculations further indicate that confined Na-carbon interactions with partial ionic character stabilize Na storage within closed pores. As a result, RTS-HC delivers a reversible capacity of 303.6 mAh g-1 at 30 mA g-1, a high ICE of 89% and a plateau contribution of 67%. It also retains 80.4% of its capacity after 1000 cycles at 500 mA g-1, outperforming the conventionally pyrolyzed counterpart. This work provides a kinetic carbonization strategy for converting coal into high-performance hard carbon anodes for sodium-ion batteries.
Hydroconversion of waste lipids to bio-jet fuel is crucial for sustainable energy development, while developing catalysts with high activity, selectivity, and stability remains a challenge. Herein, we synthesize a catalyst consisting of CrMnFeCoNi high-entropy alloy (HEA) nanoparticles supported on SAPO-11 zeolite through a thermal-driven in-situ self-assembly process. The multi-metal electronic synergy of the HEA accelerates hydrogen activation, while its entropy-stabilized nature ensures the uniform dispersion and structural integrity of the active sites. The integration of the HEA with the acidic 10-MR channels of SAPO-11 facilitates the complete conversion of oleic acid, delivering a 74% yield of jet-fuel-range hydrocarbons with an iso/n-alkane ratio of 0.87. Moreover, the catalyst showed only 17% decline in conversion after five consecutive cycles without high-temperature regeneration. On a simulated waste lipid mixture, the catalyst achieves 100% conversion, 68% jet-fuel-range yield and an iso/n ratio of 0.82. Different components of HEA/SAPO-11 catalyst show different functions, in which Ni and Co contribute to hydrogen activation and hydrodeoxygenation, Fe participates in electronic modulation of the HEA environment, while Cr and Mn preferentially interact with the SAPO-11 framework and help stabilize the alloy nanoparticles. Together with the acidic sites and shape-selective channels of SAPO-11, the HEA components can directly realize the hydroconversion of oleic acid. This work demonstrates the promise of HEA/SAPO-11 for efficient waste lipid conversion and provides a practical strategy for producing jet-fuel-range hydrocarbons.
The selectivity of two-electron oxygen reduction reaction (2e- ORR) is predominantly determined by the adsorption strength of the key intermediate *OOH on the catalyst active sites, which has often been tuned by 3d transition-metal doping. Herein, we fabricate rare earth Ce doped bismuth oxyhalide (BiOX, X = Cl, Br, I) catalysts. The built in Ce–O–Bi local configuration triggers efficient charge rearrangement and tunes the surface electron density of Ce active centers. Meanwhile, the differences in ionic radius and electronegativity among halogen species can modulate the symmetry of the Bi–O lattice, thereby forming a typical volcano-type correlation between the bond length and 2e- ORR catalytic performance. The synergistic effect of Ce doping and halogen modulation endows the 2.5%Ce-BOB catalyst with optimal 2e- ORR performance. It delivers a H2O2 selectivity of over 90% within the potential range of 0.2-0.6 V and achieves a H2O2 production rate of 2631.4 mmol g-1 h-1 at 0.1 V. Furthermore, this optimized catalyst demonstrates potential application in organic wastewater treatment, where the degradation efficiency of methylene blue (MB) reaches approximately 95% in 40 min and that of rhodamine B (RhB) approaches 99% in 15 min. This work provides new insights into the rational design of electrocatalysts and environmental applications of electrosynthesized H2O2 via the synergistic regulation of rare-earth metal doping and halogen modulation.
Sulfur poisoning remains a critical challenge for catalytic systems in gaseous pollutant abatement, as the strong chemisorptive affinity of SO2 and its derivatives toward active sites, along with the formation of thermodynamically stable sulfates, severely disrupts redox processes and leads to irreversible deactivation. This review provides a comprehensive overview of sulfur deactivation mechanisms in catalytic reactions of VOCs, CO, and NOx, highlighting competitive adsorption, formation of metal sulfides or sulfates, and poisoning effect of intermediate products. Mechanistic insights and recent advances in sulfur-tolerant catalyst design are systematically summarized. Three key strategies are highlighted: (i) interface engineering and defect design, which tailor electronic structure, charge transfer, and oxygen vacancy density to regulate sulfur-metal interactions; (ii) active component modulation, including bimetallic coupling and rare-earth incorporation, which stabilize redox cycles and suppress irreversible sulfate accumulation; and (iii) structural optimization of catalyst supports, involving high-surface-area porous architectures, protective core-shell or layered configurations, and finely tuned surface acid-base properties to enhance both sulfur resistance and reactant accessibility. The insights summarized herein are expected to guide the rational design of next-generation sulfur-tolerant catalytic systems, enabling sustained performance under realistic sulfur-containing conditions.
The photoconversion efficiency of CO2 is hindered by severe charge recombination and sluggish multi-electron kinetics at the surface reaction. For strengthening CO2 adsorption and activation process, abundant nitrogen vacancy (Nv) and –COOH groups are introduced into potassium doped carbon nitride (KCN) by mechanical ball milling and acid treatment for construting KCN treated by Mg-assisted (KCN-M2). Compared with pristine KCN (2.13 μmol·g–1·h–1), the photocatalytic CO evolution rates of KCN-M1, KCN-M2, and KCN-M3 materials increase to 6.79, 11.32, and 7.06 μmol·g–1·h–1, respectively. KCN-M2 materials also show favorable photocatalytic CO evolution at low CO2 concentrations (10% CO2 (8.91 μmol·g–1·h–1) and air (0.04% CO2 (6.16 μmol·g–1·h–1)). The comprehensive analysis reveals that Nv and –COOH groups can synergistically facilitate photogenerated electron transfer, CO2 adsorption, and water affinity. Furthermore, density functional theory (DFT) computations for CO2 conversion pathway reveal that KCN-M2 exhibits a lower energy change for the rate-determining step (*COOH → *CO) energy changes (0.82 eV) than pristine KCN (1.03 eV), confirming that Nv and –COOH groups facilitate the transformation of *COOH to *CO intermediate. The results provide insights into photocatalyst design, contributing not only to the artificial carbon cycle but also to the realization of the critical dual-carbon goals.
Owing to the scarcity of natural resources, the polyester industries have turned to synthesizing 2,5-Furandicarboxylic acid (FDCA) from 5-hydroxymethylfurfural (HMF) to replace terephthalic acid for meeting their extensive demands. Achieving efficient oxidation of cheap and available crude-HMF into FDCA presents significant challenges. Herein, a highly dispersed Fe3N nanoparticle catalyst anchored on N-doped carbon (Fe@CN) was developed for efficient aerobic oxidation of crude HMF to FDCA, a key renewable alternative to terephthalic acid. The Fe@CN catalyst delivers a 94% FDCA yield with exceptional stability under 150 °C, 3 MPa air, 3 h in aqueous solution, outperforming most non-noble metal catalysts. Structural and mechanistic studies reveal that Fe-N coordination weakens Fe-O bonds and boosts lattice oxygen mobility, accelerating the rate-determining hydroxyl oxidation step via a Mars-van Krevelen mechanism. Preferential adsorption of the HMF hydroxyl group on Lewis acidic Fe3+ sites direct the dominant pathway through 2,5-diformylfuran (DFF). Dynamic Fe2+/Fe3+ redox cycling and efficient lattice oxygen replenishment at pyridinic-N sites sustain catalytic activity. This work offers a general design principle for low-cost, robust catalysts toward sustainable biomass valorization.
Asymmetric silicon carbide (SiC) ceramic membranes exhibit significant potential for high-temperature ultrafine particle capture in industrial applications, which showed great prospects in energy and environmental areas. However, the high permeance and high strength of the ceramic membranes are often difficult to obtain simultaneously. The traditional asymmetric ceramic membranes composed of particle stacking have better mechanical strength, while their high mass transfer resistance leads to lower gas permeance. Increasing the overall porosity of ceramic membranes can effectively reduce the mass transfer resistance, but their relatively lower strength is not conducive to industrial applications. Herein, we propose a phase inversion strategy to create a defect-free and high-porosity membrane layer on a rigid macroporos support. This innovative structural design enhances the gas permeance and mechanical strength of the ceramic membrane simultaneously. The resulting ceramic membranes exhibited excellent gas permeance between 385.2 to 447.3 m3·m−2·h−1·kPa−1 with average pore size ranging from 3.26 to 3.89 μm and a bending strength exceeding 20 MPa. Notably, the Darcy permeability coefficient of the ceramic membrane prepared in this work was more than twice that of the widely recognized commercial Pall Schumalith filter (with a pore size of 5 μm) from the authoritative Pall Corporation. The computerized tomography (CT) results indicated that the membrane layer possessed high connective internal channels. Furthermore, computational fluid dynamics (CFD) simulation was employed to verify the substantial superiority of the high porous finger-like pores in reducing the mass transfer resistance. Additionally, the SiC membranes presented a superior removal efficiency of over 99.93% and an excellent regeneration performance when capturing nano-sized particles with ultrafine particles at high temperatures, demonstrating satisfactory potential in ultrafine particle capture at extreme environments.
This work targets the long-standing limitations of spinel LiMn2O4 (LMO) in electrochemical lithium extraction from salt-lake brines, including manganese dissolution, surface structural instability, and sluggish Li+ transport kinetics. To address these challenges, a fluorine-induced cooperative surface-electronic engineering strategy is proposed, which enables a distinct reconstruction of the surface electronic structure, characterized by an increased Mn3+ fraction and the generation of oxygen vacancies. The reduced binding energy of the Mn 2p peak in XPS spectra, and the upward shift of the d-band center revealed by PDOS calculations, confirm enhanced surface redox activity and ion-transport capability. Consequently, the fluorine-modified LMO exhibits significantly improved lithium extraction performance in both simulated and real brine environments with 1MF-LMO delivering the optimal performance. In simulated brine, it achieves average Li+ extraction and release rates of 18.16 and 16.45 mg g-1 h-1, representing enhancements of 159% and 229% relative to LMO. Under complex practical conditions, including lithium-rich mother liquor and West Taijinar salt-lake brine, 1MF-LMO maintains high Li+ extraction capacities of 26.51 and 30.21 mg g-1 h-1, respectively, demonstrating excellent adaptability. Furthermore, a trace amount of polyacrylonitrile (PAN) can synergistically optimize interfacial functionality, which combines interfacial electrostatic effects and size-exclusion effects that mainly suppress the co-extraction of Na+ and Mg2+ and thus significantly enhance Li+ selectivity.
The 5-hydroxymethylfurfural oxidation reaction (HMFOR) is a promising approach for biomass upgrading. However, the mechanistic complexity of HMFOR poses limitations on its widespread adoption. In particular, the competitive adsorption between HMF molecules and hydroxyl species on electrocatalyst surfaces critically governs the reaction kinetics and selectivity. Herein, a dense crystalline-amorphous (c-a) Ag/NCM heterointerface is engineered to modulate competitive adsorption for efficient HMFOR. The introduction of crystalline Ag not only promotes the electrochemical formation of active NiCo(OOH)2 species but also preferentially adsorbs HMF via the aldehyde group. As a result, the Ag/NCM catalyst delivers a markedly reduced onset potential (1.05 VRHE) and a fivefold enhancement in current density compared to NCM. In-situ Raman spectroscopy, in-situ 2-D FTIR, multipotential electrochemical measurements, and density functional theory calculations collectively reveal that Ag modulates the competitive adsorption of HMF and OH* on the c-a interface, and accelerates the rate-determining HMFCA-to-FFCA step. This study not only illuminates the adsorption facilitation mechanism at the c-a interfacial sites but also offers invaluable insights for advancing the field of biomass electrocatalysis, paving the way for more efficient and sustainable utilization of biomass resources.
Proton exchange membrane fuel cells (PEMFCs) play a crucial role in the transition toward hydrogen-based clean energy systems. However, their performance and durability are highly sensitive to internal environmental conditions, which remain difficult to monitor in real time. Traditional monitoring methods, whether intrusive or non-intrusive, often suffer from limitations such as low spatial and temporal resolution, structural complexity, or incompatibility with stack integration. This comprehensive review highlights the paradigm shift toward emerging flexible sensor technologies as a promising approach for in-situ, multi-parameter monitoring in PEMFCs. We systematically categorize and evaluate both non-intrusive and intrusive sensing strategies, detailing their operating principles, advantages, and limitations. Special emphasis is placed on flexible microsensors, which enable real-time monitoring of temperature, humidity, pressure, gas composition, voltage, and current with minimal structural disruption. We further summarize recent advances of flexible sensors for in-situ monitoring in PEMFCs according to application scenarios. The transition from single-parameter sensing to multi-parameter integration, as well as from single-cell investigations to stack-level applications, is also discussed. Finally, we examine the trade-offs between sensor integration and fuel cell performance, and propose future research directions aimed at improving sensor durability, spatial resolution, and system-level integration for intelligent PEMFC management.
Nitroaromatic reduction is one of the most valuable industrial reactions; however, the development of eco-friendly carbon-based metal-free catalysts is extremely limited by their low activities and insufficient wettability. Herein, we present a highly efficient hierarchical macro-mesoporous N,S-codoped carbon catalyst, derived from used tea featuring a superhydrophilic structure achieved through an alkaline-mediated thiourea activation carbonization strategy, for the reduction of nitroaromatic compounds. The ultrahigh-carbon macroporous structure is crucial for maximizing the exposure of the external surface area of active sites. Additionally, N,S-codoping enhances surface wettability, ensuring excellent accessibility of active sites in aqueous reactions. These outstanding advantages enable the optimized catalyst (N,S1-TC-600) to exhibit high catalytic activity in nitroaromatic reduction. Finite element method and density functional theory calculations indicate that N and S codoping within the macroporous structure results in superior catalytic performance through the synergistic effect of thermal accumulation and mass transfer enrichment on the macro-mesoporous carbon catalyst, which is driven by redistribution of charge and spin density. Furthermore, activation energy barrier calculations revealed that the optimized N,S1-TC-600 has a lower activation energy for 4-nitrophenol reduction. This work presents a valuable methodology for constructing and modulating the electronic state of highly efficient carbon-based metal-free catalysts, which may provide a general guidance for the fabrication of other carbon-based catalysts.
Frustrated Lewis pair (FLP) in metal oxides (e.g., spinel) show catalytic promise but face a trade-off between strong acidity and steric hindrance. Herein, we develop a high-temperature molten alkali etching strategy for engineering tetracoordinate iron sites (Fe3+Td) in ZnFe2O4, while using the Zn→O→Fe electron transport chain as a structural stabilizer. This spatially segregated FLP system features electron-deficient Fe3+Td (Lewis acid) and electron-rich O2- (Lewis base) sites that enhance substrate adsorption synergistically and reduce activation barriers in catalytic transfer hydrogenation (CTH). When applied to biomass-derived carbonyl compounds and representative aldehydes/ketones, the catalyst achieves >95% conversion of furfural to furfuryl alcohol (120 °C, 2 h), outperforming conventional systems. Furthermore, it maintains >95% activity over five cycles, demonstrating exceptional stability. Density Functional Theory calculations confirmed that the constructed, low-coordination, high-valent FLP has a stronger adsorption capacity for substrate and exhibits high hydrogenation ability with an activation energy of only 0.17 eV, which is far lower than that of the unconstructed sample (0.88 eV). This work breaks down the conflict barriers between high-valence and low-coordination states and provides a scalable novel strategy for designing strongly acidic, low-resistance FLP catalysts for sustainable chemistry.
Supported nickel (Ni) catalysts are widely utilized in industrial CO/CO2 hydrogenation for methane production. However, their structural sensitivity presents a significant challenge to productivity. While larger Ni particles generally favour methane formation, unsupported Ni nanoparticles (even at the micrometre scale) fail to efficient CO2 methanation. In this study, we engineered TiO2@Ni-x catalysts by depositing TiO2 onto Ni surface, along with conventional Ni/TiO2 and unsupported Ni nanoparticles (Ni-p), to explore the synergy of multi-sites in CO2 hydrogenation. The TiO2@Ni-x achieved 90.1% methane selectivity at 400 °C, while CO dominated on both Ni-p and Ni/TiO2. Temperature programmed experiments, in-situ infrared spectroscopy and theoretical modelling results revealed that TiO2@Ni-x with metal-oxide interfaces integrate excellent capabilities for H2, CO2, and CO adsorption and dissociation, enabling a complete hydrogenation pathway and high CH4 selectivity. The reactivity of CO intermediates is predominantly governed by the abundance of Ni-TiO2 interfaces and the formation of Ni-C-O-Ti bridge configurations, rather than isolated Ni surfaces. In contrast, despite having interfaces, conventional Ni/TiO2 suffered from strong metal-support interactions (SMSI) with limited H2 dissociation ability, yielding only 3.3% methane at 400 °C. This work extends the understanding of structural sensitivity beyond the electronic properties of Ni, demonstrating that the metal-oxide interface is a prerequisite for the CO intermediates adsorption and subsequent hydrogenation.
Layered transition metal oxides (LTMOs), with a unique two-dimensional framework, are research hotspots for sodium-ion battery (SIB) cathodes due to their high specific capacity, environmental benignity, structural tunability, and facile synthesis, showing great commercial potential for large-scale energy storage. However, their practical application is severely hindered by unique interfacial instability challenges during long-term Na+ (de)intercalation. These include interface strain induced by the larger radius of Na+ ions, transition metal dissolution, lattice oxygen loss, and interface cracking caused by phase transitions such as P2-O2 or O3-P2. Collectively, these issues lead to drastic capacity fading and poor electrochemical performance. Interfacial engineering is pivotal for regulating electrode-electrolyte interface properties, effectively mitigating side reactions and enhancing LTMOs stability and performance. Representative strategies include surface modification, elemental doping, multiscale structural regulation, and electrolyte/interface engineering approaches, while their practical application is restricted by material-specific limitations, unclear synergistic effects, and scalable fabrication challenges. This review summarizes recent advances in interfacial engineering for LTMOs cathodes, focusing on modification mechanisms of key strategies. It discusses how these approaches address interfacial instability, outlines current challenges, and proposes future directions for synergistic optimization, providing theoretical guidance for high-performance, long-life LTMOs cathodes in SIBs.
Low-temperature nitrogen oxides (NOx) abatement is critically hindered by catalyst deactivation in H2O- and SO2-containing atmospheres, severely limiting the practical application of NH3-selective catalytic reduction (NH3-SCR) technology. Existing strategies to improve the tolerance of Cu-based chabazite (Cu-CHA) catalysts primarily rely on external modifications, overlooking the intrinsic molecular sieving potential of their micropore structure. Herein, we propose a strategy to intrinsically enhance the water and sulfur dioxide tolerance of Cu-CHA catalyst by regulating the surface framework Al distribution and synergistically amplifying the micropore confinement effect. Therefore, a Cu-SSZ-13-M with an Al-poor surface was synthesized, which effectively reduces the number of surface-exposed active Cu species and acid sites while enhancing surface hydrophobicity, thereby suppressing NH4HSO4 formation and mitigating pore-mouth blockage. Meanwhile, the unblocked micropore channels act as a molecular-scale diffusion barrier, selectively restricting SO2 ingress and protecting intracrystalline active sites from poisoning. In the NH3-SCR reaction over 22 h in the presence of H2O and SO2, Cu-SSZ-13-M exhibits a 32% higher NOx conversion than Cu-SSZ-13-C. By integrating surface active site regulation with pore-level mass transport control, this work unveils the microscopic mechanism underlying the enhancement of intrinsic tolerance of Cu-CHA catalysts and offers a rational design strategy for highly efficient and anti-poisoning NH3-SCR catalysts.
The rapid global expansion of the electric vehicle industry has propelled lithium-ion battery (LIB) manufacturing, and recycling end-of-life LIBs is a key strategy to supply the great demand for critical metals and manage the large volume of retired batteries. Separation technology plays a key role in LIB recycling, where it differentiates value-added mineral components for future manufacturing. In this review, we introduce the functions of separation technologies in LIB recycling, present state-of-the-art industrial-scale LIB separation challenges, and analyze the energy consumption and environmental impacts of conventional separations. We then critically examine the working principles and current status of four categories of emerging separation technologies for sustainable LIB recycling: solvent-driven separations, adsorption- and ion exchange-based separations, membrane technologies, and electrochemical technologies. We further identify persistent bottlenecks across these platforms, including selectivity under realistic leachate conditions, chemical durability, reagent sustainability, and product-grade quality. Prospects for process integration and technology convergence are discussed, and a forward-looking roadmap is proposed to bridge the gap between laboratory performance and scalable, closed-loop LIB recycling.
The global energy transition is increasingly constrained by solid wastes containing arsenic (As) from copper (Cu) smelting. The selective separation of As is fundamentally hindered by strong Cu and As covalent bonding and the facile reoxidation of As species. To overcome such a bottleneck, the present study proposes a strategy utilizing waste to treat waste. Such an approach employs a one step simultaneous thermal treatment of black copper slag (BCS) and arsenic sulfide slag (ASS). The process simultaneously enables phase directed sulfidation and the selective reduction of As. By integrating thermodynamic analysis, kinetic evaluation, and Density functional theory calculations, a sulfur (S) mediated mechanism was identified. Specifically, charge transfer and orbital rearrangement cooperatively drove the cleavage of Cu and As bonds. Such a pathway directed the formation of Cu2S and facilitated the efficient release of elemental As (As0). Mass balance under optimal conditions demonstrated that the One step process achieved a Cu recovery of 97.41%, an As removal rate of 95.18%, and a Cu and As separation efficiency of 97.73%. Following BCS pretreatment, such metrics improved to 97.73%, 99.88%, and 97.52%, respectively. The recovered product contained 94.76% As0, and XRD analysis verified the nearly complete reduction of As2O3. The present study establishes a scalable synergistic control strategy for the sustainable valorization of metallurgical wastes.
The sustained generation of highly active reactive oxygen species (ROS) on transition metal oxides for the complete mineralization of formaldehyde (HCHO) at sub-ambient temperatures remains a formidable challenge. This study reports a hierarchical bird-nest-like α-MnO2 catalyst (denoted as α-MnO2-SA, where SA represents self-assembled) for HCHO purification at sub-ambient temperatures. Unlike conventional one-step precipitation, this phase-transformation-mediated route optimizes the hierarchical architecture and electronic states, significantly enhancing lattice oxygen mobility and surface oxygen vacancy density. The synergy between photogenerated carrier dynamics and surface vacancy engineering endows α-MnO2-SA with a notably low apparent activation energy of 20.5 kJ/mol, enabling 100% HCHO conversion at 0 °C. Remarkably, under the harsh conditions of −10 °C, 50% relative humidity, and an ultra-high weight hourly space velocity (WHSV) of 300 L/(g·h), the catalyst maintains over 80% removal efficiency for 10 hours without significant degradation. In situ DRIFTS and EPR analyses reveal that the unique hierarchical architecture acts as an oxygen buffer, mitigating diffusion limits in frigid environments and facilitating the Mars-van Krevelen cycle through the rapid regeneration of active species. This work provides a novel paradigm for designing robust, vacancy-rich catalysts for air purification in extreme cold environments.
