Crystal Facet Controlled Metal-Support Interaction in Uricase Mimics for Highly Efficient Hyperuricemia Treatment.

The effect of strong metal-support interaction (SMSI) has never been systematically studied in the field of nanozyme-based catalysis before. Herein, by coupling two different Pd crystal facets with MnO2, i.e., (100) by Pd cube (Pdc) and (111) by Pd icosahedron (Pdi), we observed the reconstruction of Pd atomic structure within the Pd-MnO2 interface, with the reconstructed Pdc (100) facet more disordered than Pdi (111), verifying the existence of SMSI in such coupled system. The rearranged Pd atoms in the interface resulted in enhanced uricase-like catalytic activity, with Pdc@MnO2 demonstrating the best catalytic performance. Theoretical calculations suggested that a more disordered Pd interface led to stronger interactions with intermediates during the uricolytic process. In vitro cell experiments and in vivo therapy results demonstrated excellent biocompatibility, therapeutic effect, and biosafety for their potential hyperuricemia treatment. Our work provides a brand-new perspective for the design of highly efficient uricase-mimic catalysts.

Asymmetric Assembly in Microdroplets: Efficient Construction of MOF Micromotors for Anti-Gravity Diffusion.

Janus-micromotors, as efficient self-propelled materials, have garnered considerable attention for their potential applications in non-agitated liquids. However, the design of micromotors is still challenging and with limited approaches, especially concerning speed and mobility in complex environments. Herein, a two-step spray-drying approach encompassing symmetrical assembly and asymmetrical assembly is introduced to fabricate the metal-organic framework (MOF) Janus-micromotors with hierarchical pores. Using a spray-dryer, a symmetrical assembly is first employed to prepare macro-meso-microporous UiO-66 with intrinsic micropores (<0.5 nm) alongside mesopores (≈24 nm) and macropores (≈400 nm). Subsequent asymmetrical assembly yielded the UiO-66-Janus loaded with the reducible nanoparticles, which underwent oxidation by KMnO4 to form MnO2 micromotors. The micromotors efficiently generated O2 for self-propulsion in H2O2, exhibiting ultrahigh speeds (1135 µm s-1, in a 5% H2O2 solution) and unique anti-gravity diffusion effects. In a specially designed simulated sand-water system, the micromotors traversed from the lower water to the upper water through the sand layer. In particular, the as-prepared micromotors demonstrated optimal efficiency in pollutant removal, with an adsorption kinetic coefficient exceeding five times that of the micromotors only possessing micropores and mesopores. This novel strategy fabricating Janus-micromotors shows great potential for efficient treatment in complex environments.

Investigations on Tunnel-Structure MnO2 for Utilization as a High-Voltage and Long-Life Cathode Material in Aqueous Ammonium-Ion and Hybrid-Ion Batteries.

Recently, nonmetal NH4 + ions have attracted extensive attention for use as charge carries in the field of energy storage due to their abundant resources, environmental friendliness, and low cost. However, the development of aqueous ammonium-ion batteries (AAIBs) is constrained by the absence of high-voltage and long-life materials. Herein, different tunnel-structure MnO2 materials (α-, ß-, and γ-MnO2) are utilized as cathodes for AAIBs and hybrid-ion batteries and compared, and α-MnO2 is demonstrated to exhibit the most remarkable electrochemical performance. The α-MnO2 cathode material delivers the highest discharge capacity of 219 mAh g-1 at a current density of 0.1 A g-1 and the best cyclability with a capacity retention of 95.4% after 10 000 cycles at 1.0 A g-1. Moreover, aqueous ammonium-ion and hybrid-ion (ammonium/sodium ions) full batteries are successfully constructed using α-MnO2 cathodes. This work provides a novel direction for the development of aqueous energy storage for practical applications.

Zwitterion Intercalated Manganese Dioxide Nanosheets as High-Performance Cathode Materials for Aqueous Zinc Ion Batteries.

In this study, a novel approach is introduced to address the challenges associated with structural instability and sluggish reaction kinetics of δ-MnO2 in aqueous zinc ion batteries. By leveraging zwitterionic betaine (Bet) for intercalation, a departure from traditional cation intercalation methods, Bet-intercalated MnO2 (MnO2-Bet) is synthesized. The positively charged quaternary ammonium groups in Bet form strong electrostatic interactions with the negatively charged oxygen atoms in the δ-MnO2 layers, enhancing structural stability and preventing layer collapse. Concurrently, the negatively charged carboxylate groups in Bet facilitate the rapid diffusion of H+/Zn2+ ions through their interactions, thus improving reaction kinetics. The resulting MnO2-Bet cathode demonstrates high specific capacity, excellent rate capability, fast reaction kinetics, and extended cycle life. This dual-function intercalation strategy significantly optimizes the electrochemical performance of δ-MnO2, establishing it as a promising cathode material for advanced aqueous zinc ion batteries.

Electrochemical Failure Mechanism of δ-MnO2 in Zinc Ion Batteries Induced by Irreversible Layered to Spinel Phase Transition.

Phase transitions of Mn-based cathode materials associated with the charge and discharge process play a crucial role on the rate capability and cycle life of zinc ion batteries. Herein, a microscopic electrochemical failure mechanism of Zn-MnO2 batteries during the phase transitions from δ-MnO2 to λ-ZnMn2O4 is presented via systematic first-principle investigation. The initial insertion of Zn2+ intensifies the rearrangement of Mn. This is completed by the electrostatic repulsion and co-migration between guest and host ions, leading to the formation of λ-ZnMn2O4. The Mn relocation barrier for the λ-ZnMn2O4 formation path with 1.09 eV is significantly lower than the δ-MnO2 re-formation path with 2.14 eV, indicating the irreversibility of the layered-to-spinel transition. Together with the phase transition, the rearrangement of Mn elevates the Zn2+ migration barrier from 0.31 to 2.28 eV, resulting in poor rate performance. With the increase of charge-discharge cycles, irreversible and inactive λ-ZnMn2O4 products accumulate on the electrode, causing continuous capacity decay of the Zn-MnO2 battery.

Seed-Assisted Reversible Dissolution/Deposition of MnO2 for Long-Cyclic and Green Aqueous Zinc-Ion Batteries.

Manganese oxide (MnO2) based aqueous zinc-ion batteries (AZIBs) are considered to be a promising battery for grid-scale energy storage. However, they usually suffer from the great challenge of capacity attenuation due to Mn dissolution and irreversible structural transformation. Herein, full use of the shortcomings is made to design high-performance cathode-free AZIBs. Manganese-based Prussian blue analog (Mn-PBA) is selected as a seed layer to provide a stable MnO2 electrodeposition surface. Thanks to the large specific surface area and manganophilic nature of Mn-PBA, the deposition/dissolution kinetics between Mn2+ and MnO2 are significantly enhanced. Systematic studies revealed the mechanism of MnO2 deposition-dissolution related to the reversible transformation of manganese oxide hydroxide and zinc hydroxide sulfate hydrate. Based on this, the developed cathode-free AZIBs exhibit outstanding rate performance (with a specific capacity of 273.7 mAh g-1 at 1 A g-1) and extraordinary cycle stability (maintaining a specific capacity of 52.3 mAh g-1 after 50 000 cycles at 20 A g-1). Furthermore, the AZIBs with non-toxic, biocompatible materials can be directly discarded after use, without causing pollution to the environment, which is expected to help achieve the sustainable development goals.

An Organic Acid-Alkali Coregulated Ionic Liquid Electrolyte Enabling Wide-Temperature-Range Proton Battery.

The broad applications of rechargeable batteries urge people to develop alternative energy storage devices with sustainable resources, high capacity, long cycling life, and wide-temperature operability. Aqueous proton batteries are considered as a state-of-the-art energy storage system due to their intrinsic safety and low cost. However, aqueous electrolytes have a low boiling point and narrow electrochemical stability window, limiting their applications in wide-temperature and high-energy batteries. Herein, a hybrid organic ionic liquid electrolyte with organic alkali 1-methyl-1,2,4-triazole (MTA) protonated by organic acid bis(trifluoromethysulfonyl)imide (HTFSI) as proton carriers and tetramethylene sulfone (TMS) as the solvent, noted as HTFSI-MTA-TMS, exhibited the stable electrochemical windows exceeding 5 V at -20 °C and 3.5 V at 80 °C. Benefiting from this electrolyte, the assembled MnO2-S//MoO3 button proton full battery can display an operation voltage up to 1.8 V, energy density of 44.8 Wh kg-1, and good cycling stability at room temperature when bis(trifluoromethanesulfonyl)imide manganese (II) salt (Mn(TFSI)2) is introduced into the electrolyte, and run well in a wide-temperature range (-20 °C-60 °C). The work reveals the potential of organic acid-alkali coregulated electrolytes to meet the need of energy storage in a wide-temperature range and will advance the development of high-energy proton batteries.

Acidity-Aided Surface Modification Strategy to Enhance In Situ MnO2 Deposition for High Performance Zn-MnO2 Battery Prototypes.

Zn-MnO2 batteries offer cost-effective, eco-friendly, and efficient solutions for large-scale energy storage applications. However, challenges, like irreversible cathode reactions, prolonged cyclability, and electrolyte stability during high-voltage operations limit their broader application. This study provides insight into the charge-discharge process through in situ deposition of active ß-MnO2 nanoflakes on a carbon-based current collector. The study elucidates the effect of pH and electrolyte concentration on chemical conversion reactions with Zn, in particular focus on their impact on the two-electron MnO2/Mn2+ reaction crucial for high voltage operation. The electrolyte, characterized by being relatively lean in Mn2+ and with a targeted low pH, enables extended cycling. This research achieves greater cycling durability by integrating a carbon-based cathode current collector with high density of structural defects in combination with cell architectures suitable for large-scale energy storage. A flooded stack-type Zn-MnO2 battery prototype employing the optimized electrolyte demonstrates a high discharge voltage (≈2 V) at a substantial discharge current rate of 10 mA cm-2. The battery exhibits an impressive areal capacity of ≈2 mAh cm-2, maintaining ≈100% capacity retention over 400 cycles. This research establishes a promising practical, and cost-effective cathode-free design for Zn-MnO2 batteries, that minimizes additional processing and assembly costs.

α-MnO2 Cathode with Oxygen Vacancies Accelerated Affinity Electrolyte for Dual-Ion Co-Encapsulated Aqueous Aluminum Ion Batteries.

Aluminum batteries (ABs) are identified as one of the most promising candidates for the next generation of large-scale energy storage elements because of their efficient three-electron reaction. Compared to ionic electrolytes, aqueous aluminum-ion batteries (AAIBs) are considered safer, less costly, and more environmentally friendly. However, considerable cycling performance is a key issue limiting the development of AAIBs. Stable, efficient, and electrolyte-friendly cathodes are most desirable for AAIBs. Herein, a rod-shaped defect-rich α-MnO2 is designed as a cathode, which is capable to deliver high performance with stable cycling for 180 cycles at 500 mA g-1 and maintains a discharge specific capacity of ≈100 mAh g-1. In addition, the infiltrability simulation is effectively utilized to corroborate the rapid electrochemical reaction brought about by the defective mechanism. With the formation of oxygen vacancies, the dual embedding of protons and metal ions is activated. This work provides a brand-new design for the development and characterization of cathodes for AAIBs.

Boosting the Energy Density of Bowl-Like MnO2@Carbon Through Lithium-Intercalation in a High-Voltage Asymmetric Supercapacitor with "Water-In-Salt" Electrolyte.

Highly concentrated "'water-in-salt"' (WIS) electrolytes are promising for high-performance energy storage devices due to their wide electrochemical stability window. However, the energy storage mechanism of MnO2 in WIS electrolytes-based supercapacitors remains unclear. Herein, MnO2 nanoflowers are successfully grown on mesoporous bowl-like carbon (MBC) particles to generate MnO2/MBC composites, which not only increase electroactive sites and inhibit the pulverization of MnO2 particles during the fast charging/discharging processes, but also facilitate the electron transfer and ion diffusion within the whole electrode, resulting in significant enhancement of the electrochemical performance. An asymmetric supercapacitor, assembled with MnO2/MBC and activated carbon (AC) and using 21 m LiTFSI solution as the WIS electrolyte, delivers an ultrahigh energy density of 70.2 Wh kg-1 at 700 W kg-1, and still retains 24.8 Wh kg-1 when the power density is increased to 28 kW kg-1. The ex situ XRD, Raman, and XPS measurements reveal that a reversible reaction of MnO2 + xLi+ + xe-↔LixMnO2 takes place during charging and discharging. Therefore, the asymmetric MnO2/MBC//AC supercapacitor with LiTFSI electrolyte is actually a lithium-ion hybrid supercapacitor, which can greatly boost the energy density of the assembled device and expand the voltage window.

Revisiting the Charging Mechanism of α-MnO2 in Mildly Acidic Aqueous Zinc Electrolytes.

In recent years, there have been extensive debates regarding the charging mechanism of MnO2 cathodes in aqueous Zn electrolytes. The discussion centered on several key aspects including the identity of the charge carriers contributing to the overall capacity, the nature of the electrochemical process, and the role of the zinc hydroxy films that are reversibly formed during the charging/discharging. Intense studies are also devoted to understanding the effect of the Mn2+ additive on the performance of the cathodes. Nevertheless, it seems that a consistent explanation of the α-MnO2 charging mechanism is still lacking. To address this, a step-by-step analysis of the MnO2 cathodes is conducted. Valuable information is obtained by using in situ electrochemical quartz crystal microbalance with dissipation (EQCM-D) monitoring, supplemented by solid-state nuclear magnetic resonance (NMR), X-ray diffraction (XRD) in Characterization of Materials, and pH measurements. The findings indicate that the charging mechanism is dominated by the insertion of H3O+ ions, while no evidence of Zn2+ intercalation is found. The role of the Mn2+ additive in promoting the generation of protons by forming MnOOH, enhancing the stability of Zn/α-MnO2 batteries is thoroughly investigated. This work provides a comprehensive overview on the electrochemical and the chemical reactions associated with the α-MnO2 electrodes, and will pave the way for further development of aqueous cathodes for Zn-ion batteries.

Carbon Nanotube Network Induces Porous Deposited MnO2 for High-Areal Capacity Zn/Mn Batteries.

Mn2+/MnO2 aqueous battery is a promising candidate for large-scale energy storage owing to its feature of low-cost and abundant crustal reserves. However, the inherent MnO2 shedding issue results in a limited areal capacity and poor cycling life, which prohibits its further commercialization. In this manuscript, it is revealed that the cause of shedding is the cracking of MnO2 layer due to stress. To circumvent this challenge, carbon nanotubes framework is introduced on pristine carbon felt, which provides more deposition sites and induces the formation of a porous deposition layer. Compared to the dense deposition layer on pristine carbon felt, the porous structure can effectively avoid cracking and subsequent shedding issue. Moreover, the porous deposited layer is conducive to proton diffusion and rich in defects, which facilitates the subsequent dissolution reaction. As results, the assembled Zn/Mn battery demonstrates more than 200 cycles with the areal capacity of 15 mAh cm-2 at 40 mA cm-2. Even with a high areal capacity of 40 mAh cm-2, it can still run for more than 60 cycles. This breakthrough paves a way toward practical manganese-based batteries, bringing us closer to achieve cost-effective batteries.

Ultralong Bistable, Electrolytic MnO2-Based, Electrochromic Battery Enabled by Porous, Low-Barrier, Hydroxylated TiO2 Interface.

Electrochromic (EC) battery technology shows great potential in future "zero-energy building" by controlling outdoor solar transmission to tune heat gain as well as storing the consumed energy to reuse across other building systems. However, challenges still exist in exploring an electrochemical system to satisfy requirements on both ultra-long optical memory (also called bistability) without continuous power supply and high energy density. Herein, an EC battery is proposed to demonstrate ultra-long bistability (>760 h) based on the reversible deposition and dissolution of manganese oxide (MnO2) without the addition of any mediators. A porous low-barrier hydroxylated titanium dioxide (TiO2) interface is incorporated to synergistically enrich Mn2+-affinity active sites for deposition and effectively reduce the electron transport barrier of MnO2 for dissolution, thereby significantly improving the reversibility, high optical modulation (60.2% at 400 nm), and energy density (352 mAh m-2). The modification strategy is also verified on the cathode-less button cells with a much higher average coulombic efficiency (99.9%) compared to the batteries without the porous hydroxylated TiO2 interface (74.6%). These achievements lay a foundation for advancements in both electrochromism and Zn-Mn aqueous batteries.

An Efficient MnO2 Photocathode with an Excellent SnO2 Electron Transport Layer for Photo-Accelerated Zinc Ion Batteries.

Photo-accelerated rechargeable batteries play a crucial role in fully utilizing solar energy, but it is still a challenge to fabricate dual-functional photoelectrodes with simultaneous high solar energy harvesting and storage. This work reports an innovative photo-accelerated zinc-ion battery (PAZIB) featuring a photocathode with a SnO2@MnO2 heterojunction. The design ingeniously combines the excellent electronic conductivity of SnO2 with the high energy storage and light absorption capacities of MnO2. The capacity of the SnO2@MnO2-based PAZIB is ≈598 mAh g-1 with a high photo-conversion efficiency of 1.2% under illumination at 0.1 A g-1, which is superior to that of most reported MnO2-based ZIB. The boosting performance is attributed to the synergistic effect of enhanced photogenerated carrier separation efficiency, improved conductivity, and promoted charge transfer by the SnO2@MnO2 heterojunction, which is confirmed by systematic experiments and theoretical simulations. This work provides valuable insights into the development of dual-function photocathodes for effective solar energy utilization.

γ-MnO2 as an Electron Reservoir for RuO2 Oxygen Evolution Catalyst in Acidic Media.

Developing highly active and durable catalysts in acid conditions remains an urgent issue due to the sluggish kinetics of oxygen evolution reaction (OER). Although RuO2 has been a state-of-the-art commercial catalyst for OER, it encounters poor stability and high cost. In this study, the electronic reservoir regulation strategy is proposed to promote the performance of acidic water oxidation via constructing a RuO2/MnO2 heterostructure supported on carbon cloth (CC) (abbreviated as RuO2/MnO2/CC). Theoretical and experimental results reveal that MnO2 acts as an electron reservoir for RuO2. It facilitates electron transfer from RuO2, enhancing its activity prior to OER, and donates electrons to RuO2, improving its stability after OER. Consequently, RuO2/MnO2/CC exhibits better performance compared to commercial RuO2, with an ultrasmall overpotential of 189 mV at 10 mA cm-2 and no signs of deactivation even after 800 h of electrolysis in 0.5 m H2SO4 at 10 mA cm-2. When applied as the anode in a proton exchange membrane water electrolyzer, the cost-efficient RuO2/MnO2/CC catalyst only requires a cell voltage of 1.661 V to achieve the water-splitting current of 1 A cm-2, and the noble metal cost is as low as US$ 0.00962 cm-2, indicating potential for practical applications.

Signal-off nanozyme-based colorimetric aptasensor for sensitive detection of ampicillin using MnO2 nanoflowers and gold nanoparticles.

The combination of nanomaterials possessing distinct characteristics and the precision of aptamers facilitates the creation of biosensors that exhibit exceptional selectivity and sensitivity. In this manuscript, we present a highly sensitive aptasensor that utilizes the distinctive characteristics of MnO2 nanoflowers and gold nanoparticles to selectively detect ampicillin (AMP). In this aptasensor, the mechanism of signal change is attributed to the difference in the oxidase-mimicking activity of MnO2 nanoflowers in the presence of a free sequence. The inclusion of AMP hindered the creation of a double-stranded DNA configuration through its binding to the aptamer, resulting in an observable alteration in absorbance. The relative absorbance varied linearly with the concentration of AMP in the range of 70 pM to 10 nM with a detection limit of 21.7 pM. In general, the colorimetric aptasensor that has been developed exhibits exceptional selectivity and remarkable stability. It also demonstrates favorable performance in human serum, making it a highly reliable diagnostic tool. Additionally, its versatility is noteworthy as it holds great potential for detecting various antibiotics present in complex samples by merely replacing the utilized sequences with new ones.

Zn-doped hollow cubic MnO2 as a high-performance cathode material for Zn ion batteries.

Manganese-based compounds have the characteristics of high theoretical capacity, low cost and stable performance, thus become a research hotspot for cathode materials of zinc-ion batteries (ZIBs). However, in the process of charging and discharging, it is accompanied by problems such as structural collapse and low conductivity, which resulted in severe capacity degration during cycles. In this paper, a kind of Zn2+ doped MnO2 hollow cube cathode material (Zn-MnO2) was prepared by self-sacrificing template method. The Zn2+ doped in MnO2 crystals can induce oxygen vacancies in the structure, thereby improving the structural stability ion diffusion coefficient and electrical conductivity of the material. After 100 cycles at 0.3 A g-1, the high specific capacity of 281.2 mA h g-1 is still maintained. Through ex-situ XPS and ex-situ XRD tests, the mechanism of charge-discharge process was discussed. The results show that the storage mechanism of Zn-MnO2 is H+ and Zn2+ insertion/removal and Mn3+/Mn2+ two-electron reaction pathway. The total state density (TDOS) and partial state density (PDOS) of Zn-MnO2 and MnO2 further demonstrated that the doping of Zn2+ enhanced the electron conductivity and is beneficial to the electron transfer during the electrochemical reaction.

Green synthesis of MnO2 NPs using Arabic gum: assessing its potential antiviral activity against influenza A/H1N1.

BACKGROUND: The antiviral properties of metal nanoparticles against various viruses, including those resistant to drugs, are currently a subject of intensive research. Recently, the green synthesis of nanoparticles and their anti-viral function have attracted a lot of attention. Previous studies have shown promising results in the use of Arabic gum for the green synthesis of nanoparticles with strong antiviral properties. In this study we aimed to investigate the antiviral effects of MnO2 nanoparticles (MnO2-NPs) synthesized using Arabic gum, particularly against the influenza virus. METHODS: Arabic gum was used as a natural polymer to extract and synthesize MnO2-NPs using a green chemistry approach. The synthesized MnO2-NPs were characterized using SEM and TEM. To evaluate virus titration, cytotoxicity, and antiviral activity, TCID50, MTT, and Hemagglutination assay (HA) were performed, respectively. Molecular docking studies were also performed to investigate the potential antiviral activity of the synthesized MnO2-NPs against the influenza virus. The molecular docking was carried out using AutoDock Vina software followed by an analysis with VMD software to investigate the interaction between Arabic gum and the hemagglutinin protein. RESULTS: Simultaneous combination treatment with the green-synthesized MnO2-NPs resulted in a 3.5 log HA decrement and 69.7% cellular protection, which demonstrated the most significant difference in cellular protection compared to the virus control group (p-value < 0.01). The docking results showed that binding affinities were between - 3.3 and - 5.8 kcal/mole relating with the interaction between target with MnO2 and beta-D-galactopyranuronic acid, respectively. CONCLUSION: The results of the study indicated that the MnO2-NPs synthesized with Arabic gum had significant antiviral effects against the influenza virus, highlighting their potential as a natural and effective treatment for inhibition of respiratory infections.

NiO/MnO2coated on carbon felt as an electrode material for supercapacitor applications.

Transition metal oxides have demonstrated excellent capability for charge storage when used in supercapacitor electrodes. This study undertook the hydrothermal synthesis of bimetallic nickel and manganese oxide (NiO/MnO2) on a carbon-felt (CF) substrate. NiO/MnO2/CF electrode was characterized and examined in a three-electrode system in a potassium hydroxide electrolyte. Cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge analyses revealed Faradaic behavior during charge storage, a specific capacity of 1627 F g-1, and a stability of 96.8% after 5000 consecutive charge-discharge cycles. Subsequent investigations were conducted in a two-electrode system for constructing a symmetrical supercapacitor using the NiO/MnO2/CF electrode. The energy and power densities were determined as 43Wh kg-1and 559 W kg-1. Additionally, the stability of the constructed supercapacitor device was examined over 5000 consecutive cycles, verifying a 92% stability through charge-discharge cycles. Finally, the fabricated supercapacitor was utilized to power an LED lamp, successfully maintaining the illumination for 53 s.

Water-Driven Surface Lattice Oxygen Activation in MnO2 for Promoted Low-Temperature NH3-SCR.

Water is ubiquitous in various heterogeneous catalytic reactions, where it can be easily adsorbed, chemically dissociated, and diffused on catalyst surfaces, inevitably influencing the catalytic process. However, the specific role of water in these reactions remains unclear. In this study, we innovatively propose that H2O-driven surface lattice oxygen activation in γ-MnO2 significantly enhances low-temperature NH3-SCR. The proton from water dissociation activates the surface lattice oxygen in γ-MnO2, giving rise to a doubling of catalytic activity (achieving 90% NO conversion at 100 °C) and remarkable stability. Comprehensive in situ characterizations and calculations reveal that spontaneous proton diffusion to the surface lattice oxygen reduces the orbital overlap between the protonated oxygen atom and its neighboring Mn atom. Consequently, the Mn-O bond is weakened and the surface lattice oxygen is effectively activated to provide excess oxygen vacancies available for converting O2 into O2-. Therefore, the redox property of Mn-H is improved, leading to enhanced NH3 oxidation-dehydrogenation and NO oxidation processes, which are crucial for low-temperature NH3-SCR. This work provides a deeper understanding and fresh perspectives on the water promotion mechanism in low-temperature NOx elimination.