Interfacial Engineering Boosting the Activity and Stability of MIL-53(Fe) toward Electrocatalytic Nitrogen Reduction.

The electrochemical nitrogen reduction reaction (eNRR) has emerged as a promising strategy for green ammonia synthesis. However, it suffers unsatisfactory reaction performance owing to the low aqueous solubility of N2 in aqueous solution, the high dissociation energy of N≡N, and the unavoidable competing hydrogen evolution reaction (HER). Herein, a MIL-53(Fe)@TiO2 catalyst is designed and synthesized for highly efficient eNRR. Relative to simple MIL-53(Fe), MIL-53(Fe)@TiO2 achieves a 2-fold enhancement in the Faradaic efficiency (FE) with an improved ammonia yield rate by 76.5% at -0.1 V versus reversible hydrogen electrode (RHE). After four cycles of electrocatalysis, MIL-53(Fe)@TiO2 can maintain a good catalytic activity, while MIL-53(Fe) exhibits a significant decrease in the NH3 yield rate and FE by 79.8 and 82.3%, respectively. Benefiting from the synergetic effect between TiO2 and MIL-53(Fe) in the composites, Fe3+ ions can be greatly stabilized in MIL-53(Fe) during the eNRR process, which greatly hinders the catalyst deactivation caused by the electrochemical reduction of Fe3+ ions. Further, the charge transfer ability in the interface of composites can be improved, and thus, the eNRR activity is significantly boosted. These findings provide a promising insight into the preparation of efficient composite electrocatalysts.

Selection of reference genes in liproxstatin-1-treated K562 Leukemia cells via RT-qPCR and RNA sequencing.

BACKGROUND: Reverse transcription quantitative polymerase chain reaction (RT-qPCR) can accurately detect relative gene expression levels in biological samples. However, widely used reference genes exhibit unstable expression under certain conditions. METHODS AND RESULTS: Here, we compared the expression stability of eight reference genes (RPLP0, RPS18, RPL13, EEF1A1, ß-actin, GAPDH, HPRT1, and TUBB) commonly used in liproxstatin-1 (Lip-1)-treated K562 cells using RNA-sequencing and RT-qPCR. The expression of EEF1A1, ACTB, GAPDH, HPRT1, and TUBB was considerably lower in cells treated with 20 µM Lip-1 than in the control, and GAPDH also showed significant downregulation in the 10 µM Lip-1 group. Meanwhile, when we used geNorm, NormFinder, and BestKeeper to compare expression stability, we found that GAPDH and HPRT1 were the most unstable reference genes among all those tested. Stability analysis yielded very similar results when geNorm or BestKeeper was used but not when NormFinder was used. Specifically, geNorm and BestKeeper identified RPL13 and RPLP0 as the most stable genes under 20 µM Lip-1 treatment, whereas RPL13, EEF1A1, and TUBB were the most stable under 10 µM Lip-1 treatment. TUBB and EEF1A1 were the most stable genes in both treatment groups according to the results obtained using NormFinder. An assumed most stable gene was incorporated into each software to validate the accuracy. The results suggest that NormFinder is not an appropriate algorithm for this study. CONCLUSIONS: Stable reference genes were recognized using geNorm and BestKeeper but not NormFinder. Overall, RPL13 and RPLP0 were the most stable reference genes under 20 µM Lip-1 treatment, whereas RPL13, EEF1A1, and TUBB were the most stable genes under 10 µM Lip-1 treatment.

Resistance exercise promotes the resolution and recanalization of deep venous thrombosis in a mouse model via SIRT1 upregulation.

BACKGROUND: Early exercise for acute deep venous thrombosis (DVT) improves the patient's symptoms and does not increase the risk of pulmonary embolism. However, information about its effect on thrombus resolution is limited. The aim of this study was to investigate the role of resistance exercise (RE) in thrombus resolution and recanalization and determine its underlying mechanisms.  METHODS: Ninety-six C57BL/6 J mice were randomly divided into four groups: Control group (C, n = 24); DVT group (D, n = 24); RE + DVT group (ED, n = 24); and inhibitor + RE + DVT group (IED, n = 24). A DVT model was induced by stenosis of the inferior vena cava (IVC). After undergoing IVC ultrasound within 24 h post-operation to confirm DVT formation, mice without thrombosis were excluded. Other mice were sacrificed and specimens were obtained 14 or 28 days after operation. Thrombus-containing IVC was weighed, and the thrombus area and recanalization rate were calculated using HE staining. Masson's trichrome staining was used to analyze the collagen content. RT-PCR and ELISA were performed to examine IL-6, TNF-α, IL-10, and VEGF expression levels. SIRT1 expression was assessed using immunohistochemistry staining and RT-PCR. VEGF-A protein expression and CD-31-positive microvascular density (MVD) in the thrombus were observed using immunohistochemistry.  RESULTS: RE did not increase the incidence of pulmonary embolism. It reduced the weight and size of the thrombus and the collagen content. Conversely, it increased the recanalization rate. It also decreased the levels of the pro-inflammatory factors IL-6 and TNF-α and increased the expression levels of the anti-inflammatory factor IL-10. RE enhanced VEGF and SIRT1 expression levels and increased the MVD in the thrombosis area. After EX527 (SIRT1 inhibitor) was applied, the positive effects of exercise were suppressed. CONCLUSIONS: RE can inhibit inflammatory responses, reduce collagen deposition, and increase angiogenesis in DVT mice, thereby promoting thrombus resolution and recanalization. Its underlying mechanism may be associated with the upregulation of SIRT1 expression.

Efficiently Integrated Desulfurization from Natural Gas over Zn-ZIF-Derived Hierarchical Lamellar Carbon Frameworks.

Selective removal of carbonyl sulfide (COS) and hydrogen sulfide (H2S) is the key step for natural gas desulfurization due to the highly toxic and corrosive features of these gaseous sulfides, and efficient and stable desulfurizers are urgently needed in the industry. Herein, we report a class of nitrogen-functionalized, hierarchically lamellar carbon frameworks (N-HLCF-xs), which are obtained from the structural transformation of Zn zeolitic imidazolate frameworks via controllable carbonization. The N-HLCF-xs possess the desirable characteristics of large Brunauer-Emmett-Teller surface areas (645-923 m2/g), combined primary three-dimensional microporosity and secondary two-dimensional lamellar microstructure, and high density of nitrogen base sites with enhanced pyridine ratio (17.52 wt %, 59.91%). The anchored nitrogen base sites in N-HLCF-xs show improved accessibility, which boosts their interaction with acidic COS and H2S. As expected, N-HLCF-xs can be employed as multifunctional and efficient desulfurizers for selective removal of COS and H2S from natural gas. COS was first transformed into H2S via catalytic hydrolysis, and the produced H2S was then captured and separated and catalyzed oxidation into elemental sulfur. The above continuous processes can be achieved with solo N-HLCF-xs, giving extremely high efficiencies and reusability. Their integrated desulfurization performance was better than many desulfurizers used in the area, such as activated carbon, ß zeolite, MIL-101(Fe), K2CO3/γ-Al2O3, and FeOx/TiO2.

Highly Poison-Resistant Single-Atom Co-N4 Active Sites with Superior Operational Stability over 460 h for H2 S Catalytic Oxidation.

Efficient catalytic elimination of hydrogen sulfide (H2 S) with high activity and durability in nature gas and blast-furnace gas is very critical for both fundamental catalytic research and applied environmental chemistry. Herein, atomically dispersed Co atom catalysts with Co-N4 sites that can transform H2 S into S with conversion rate of ≈100% are designed and prepared. The representative 4Co-N/NC achieves a sulfur yield of nearly 100% and TOF(Co) of 869 h-1 at 180 °C. Importantly, remarkable long-term durability is achieved as well, with no obvious loss of catalytic activity in the run of 460 h, outperforming most of the reported catalysts. The short bond length and strong cooperation of Co-N are beneficial to improve the structural stability of the Co-N4 centers, and significantly enhanced resistance of water and sulfation over single-atom Co-catalyst. The present mechanism involves the stepwise hydrogen transfer process via the adsorbed *HOO and *HS intermediates.

A New Defect Pyrochlore Oxide Sn1.06Nb2O5.59F0.97: Synthesis, Noble Metal Hybrids, and Photocatalytic Applications.

Noble metal nanoparticles have attracted considerable attention due to their useful capabilities as heterogeneous catalysts. However, they are usually prepared using various organic stabilizing agents that negatively affect their catalytic activities. Herein, we report a facile, clean, and effective method for synthesizing supported ultrafine noble metal nanoparticles by utilizing the reductive property of a new pyrochlore oxide: Sn1.06Nb2O5.59F0.97 (SnNbOF). Ultrafine Au, Pd, and Pt nanoparticles or clusters are homogeneously distributed on the SnNbOF surface. In addition, the atomic cavities and ion-exchange properties of pyrochlore-type SnNbOF can facilitate the synthesis of atomic Ag dispersed within the framework of SnNbOF. Noble metal-SnNbOF hybrids can be obtained in one step at room temperature, and no foreign reducing agents or stabilizing organics are required for the synthesis. We also show that the fabricated hybrids exhibit promising photocatalytic properties for ethylene oxidation and CO2 reduction.

Constructing a MoS2 QDs/CdS Core/Shell Flowerlike Nanosphere Hierarchical Heterostructure for the Enhanced Stability and Photocatalytic Activity.

MoS2 quantum dots (QDs)/CdS core/shell nanospheres with a hierarchical heterostructure have been prepared by a simple microwave hydrothermal method. The as-prepared samples are characterized by XRD, TEM, SEM, UV-VIS diffuse reflectance spectra (DRS) and N2-sorption in detail. The photocatalytic activities of the samples are evaluated by water splitting into hydrogen. Results show that the as-prepared MoS2 QDs/CdS core/shell nanospheres with a diameter of about 300 nm are composed of the shell of CdS nanorods and the core of MoS2 QDs. For the photocatalytic reaction, the samples exhibit a high stability of the photocatalytic activity and a much higher hydrogen evolution rate than the pure CdS, the composite prepared by a physical mixture, and the Pt-loaded CdS sample. In addition, the stability of CdS has also been greatly enhanced. The effect of the reaction time on the formations of nanospheres, the photoelectric properties and the photocatalytic activities of the samples has been investigated. Finally, a possible photocatalytic reaction process has also been proposed.

Covalent Triazine-Based Frameworks as Visible Light Photocatalysts for the Splitting of Water.

Covalent triazine-based frameworks (CTFs) with a graphene-like layered morphology have been controllably synthesized by the trifluoromethanesulfonic acid-catalyzed nitrile trimerization reactions at room temperature via selecting different monomers. Platinum nanoparticles are well dispersed in CTF-T1, which is ascribed to the synergistic effects of the coordination of triazine moieties and the nanoscale confinement effect of CTFs. CTF-T1 exhibits excellent photocatalytic activity and stability for H2 evolution in the presence of platinum under visible light irradiation (λ ≥ 420 nm). The activity and stability of CTF-T1 are comparable to those of g-C3 N4 . Importantly, as a result of the tailorable electronic and spatial structures of CTFs that can be achieved through the judicial selection of monomers, CTFs not only show great potential as organic semiconductor for photocatalysis but also may provide a molecular-level understanding of the inherent heterogeneous photocatalysis.

Photocatalytic reduction of CO2 with H2O to CH4 on Cu(I) supported TiO2 nanosheets with defective {001} facets.

Highly dispersed Cu2O clusters loaded on TiO2 nanosheets with dominant exposed {001} facets are prepared by a hydrothermal treatment followed by photodeposition. The physicochemical properties of the as-prepared samples are characterized carefully. The deposition position and chemical state of the Cu2O clusters are characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, EPR spectroscopy, and in situ CO-adsorbed FTIR spectroscopy, respectively. The results show that in situ Cu deposition leads to in situ formation of abundant oxygen vacancies (Vo) on the surface of the TiO2 nanosheets. Interestingly, the co-existence of Vo and Cu2O clusters could promote the photoactivity of CO2 reduction efficiently. The surface Vo play a significant role in the reduction of CO2. Meanwhile, the deposited Cu(I) species serve also as active sites for the formation of CH4, and then protect CH4 from degradation by generated oxidation species. For the photoreduction of CO2 to CH4, it is found that the content level of Cu2O has a significant influence on the activity. Cu-TiO2-1.0 shows the highest photocatalytic activity, which is over 30 times higher than that of the parent TiO2. This great enhancement of photocatalytic activity may be contributed by high CO2 adsorption capacity, high electron mobility, and high concentration of Vo. However, the effect of the surface area of the samples on the activity is negligible. All of this evidence is obtained by CO2-sorption, electrochemistry, in situ FTIR spectroscopy, in situ ERP techniques, etc. The reaction intermediates are detected by in situ FTIR spectroscopy. Finally, a probable mechanism is proposed based on the experimental results. It is hoped that our work could render one of the most effective strategies to achieve advanced properties over photofunctional materials for solar energy conversion of CO2.

Facile and rapid synthesis of pyrochlore W2O6 x H2O nanoplate via a fluorinion-assisted hydrothermal process.

Pyrochlore W2O6 x H2O were successfully prepared via a facile and rapid hydrothermal process in the presence of fluorinion. It is worth noting that our developed method can efficiently overcome the tedious process in the preparation of nanostructured tungstic oxide in the previous reports. The as-prepared samples have been characterized by XRD, SEM and TEM. Results showed the morphologies of the samples were nanoplate and the thickness of the plate was estimated at about several nanometers. TEM image further revealed that the plates were trigonal-like with equal lengths of about 300 nm. Furthermore the selected area electron diffraction (SAED) pattern taken from a single nanoplate indicated that the nanoplates were the single crystals with a preferential growth direction along the [011] direction. The effect of the additive ions on the formation has also been discussed. It was found that the fluorinion played a key role in the formation of W2O6 x H2O nanoplates. It is hoped that our work could provide a new insight into the facile and rapid preparation of metal oxide nanomaterials.

Monolayer HNb3O8 for selective photocatalytic oxidation of benzylic alcohols with visible light response.

Monolayer HNb3O8 2D nanosheets have been used as highly chemoselective and active photocatalysts for the selective oxidation of alcohols. The nanosheets exhibit improved photocatalytic activity over their layered counterparts. Results of in situ FTIR, DRS, ESR, and DFT calculations show the formation of surface complexes between the Lewis acid sites on HNb3O8 2D nanosheets and alcohols. These complexes play a key role in the photocatalytic activity of the material. Furthermore, the unique structural features of the nanosheets contributed to their high photocatalytic activity. An electron transition from the coordinated alcohol species to surface Nb atoms takes place and initiates the aerobic oxidation of alcohols with high product selectivity under visible light irradiation. This reaction process is distinct from that of classic semiconductor photocatalysis.

Dual-channel cathodic electrochemiluminescence of luminol induced by injection of hot electrons on a niobate semiconductor modified electrode.

In this paper, a new niobate semiconductor photocatalyst Sr(0.4)H(1.2)Nb(2)O(6)·H(2)O (HSN) nanoparticle was applied to investigate the cathodic electrochemiluminescent (ECL) behavior of luminol for the first time. The results presented here demonstrated that there were two ECL peaks of luminol at the cathodic potential attributed to immobilization of HSN on the electrode surface. It is implied that HSN can be electrically excited and injected electrons into aqueous electrolytes from this electrode under a quite low potential that only excites luminol. A mechanism for this luminol-ECL system on HSN/GCE has been proposed. Additionally, this HSN/GCE has lots of advantages, such as high stability, good anti-interference ability, simple instrumentation, rapid procedure and ultrasensitive ECL response. It is envisioned that this HSN/GCE has further applications in biosensors.

Template-free synthesis of a CdSnO3·3H2O hollow-nanocuboid photocatalyst via a facile microwave hydrothermal method.

A CdSnO3·3H2O hollow-nanocuboid photocatalyst was successfully synthesized via a facile template-free microwave hydrothermal method for the first time. The as-prepared samples were characterized by x-ray diffraction, UV-vis diffuse reflectance spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis and x-ray photoelectron spectroscopy. Moreover, samples prepared under different reaction times were analyzed by transmission electron microscopy to investigate the formation process of the CdSnO3·3H2O hollow-nanocuboids. Based on this result, a possible mechanism for the formation process was proposed. The sample prepared at 160 °C for 2 h at pH 11 exhibited the best photocatalytic activity and stability for the degradation of gaseous benzene under UV irradiation (λ = 254 nm) as compared with the other samples. The conversion and mineralization rates of benzene were about 12.5% and 67%, respectively. The mineralization rate was twice as high as that of commercial TiO2 (Degussa Co.). Furthermore, the excellent stability for the benzene decomposition was attributed to the positive charge on the catalyst surface, which was analyzed both by electron spin resonance and Zeta-potentials.

A TaON nano-photocatalyst with low surface reduction defects for effective mineralization of chlorophenols under visible light irradiation.

TaON nanoparticles with low surface reduction defect sites were successfully constructed by a simple nitridation approach using Ta2O5·nH2O as a precursor. Large amounts of crystal water in Ta2O5·nH2O are considered as a parclose to prohibit Ta(5+) from being reduced in the nitridation process with NH3 gas. Urea was also used in the synthesis, acting as a co-nitridation agent together with NH3 but also as a porogen for creating nanopores in TaON frameworks. The as-prepared TaON catalyst was evaluated by environmental purification of organic pollutants in water, as exemplified here by mineralization of phenol and its chloroderivatives in aqueous phase under visible light irradiation. Results revealed that a lower defect density of TaON, as well as its nanopore structure and smaller particle size, contribute to the promotion in both electron-hole separation and interfacial charge-transfer in materials surface/interface, being the main reasons for the enhanced photocatalytic performance.

Long-term gridded land evapotranspiration reconstruction using Deep Forest with high generalizability.

Previous datasets have limitations in generalizing evapotranspiration (ET) across various land cover types due to the scarcity and spatial heterogeneity of observations, along with the incomplete understanding of underlying physical mechanisms as a deeper contributing factor. To fill in these gaps, here we developed a global Highly Generalized Land (HG-Land) ET dataset at 0.5° spatial resolution with monthly values covering the satellite era (1982-2018). Our approach leverages the power of a Deep Forest machine-learning algorithm, which ensures good generalizability and mitigates overfitting by minimizing hyper-parameterization. Model explanations are further provided to enhance model transparency and gain new insights into the ET process. Validation conducted at both the site and basin scales attests to the dataset's satisfactory accuracy, with a pronounced emphasis on the Northern Hemisphere. Furthermore, we find that the primary driver of ET predictions varies across different climatic regions. Overall, the HG-Land ET, underpinned by the interpretability of the machine-learning model, emerges as a validated and generalized resource catering to scientific research and various applications.

2D MXenes polar catalysts for multi-renewable energy harvesting applications.

The synchronous harvesting and conversion of multiple renewable energy sources for chemical fuel production and environmental remediation in a single system is a holy grail in sustainable energy technologies. However, it is challenging to develop advanced energy harvesters that satisfy different working mechanisms. Here, we theoretically and experimentally disclose the use of MXene materials as versatile catalysts for multi-energy utilization. Ti3C2TX MXene shows remarkable catalytic performance for organic pollutant decomposition and H2 production. It outperforms most reported catalysts under the stimulation of light, thermal, and mechanical energy. Moreover, the synergistic effects of piezo-thermal and piezo-photothermal catalysis further improve the performance when using Ti3C2TX. A mechanistic study reveals that hydroxyl and superoxide radicals are produced on the Ti3C2TX under diverse energy stimulation. Furthermore, similar multi-functionality is realized in Ti2CTX, V2CTX, and Nb2CTX MXene materials. This work is anticipated to open a new avenue for multisource renewable energy harvesting using MXene materials.

Scalable and switchable CO2-responsive membranes with high wettability for separation of various oil/water systems.

Smart membranes with responsive wettability show promise for controllably separating oil/water mixtures, including immiscible oil-water mixtures and surfactant-stabilized oil/water emulsions. However, the membranes are challenged by unsatisfactory external stimuli, inadequate wettability responsiveness, difficulty in scalability and poor self-cleaning performance. Here, we develop a capillary force-driven confinement self-assembling strategy to construct a scalable and stable CO2-responsive membrane for the smart separation of various oil/water systems. In this process, the CO2-responsive copolymer can homogeneously adhere to the membrane surface by manipulating the capillary force, generating a membrane with a large area up to 3600 cm2 and excellent switching wettability between high hydrophobicity/underwater superoleophilicity and superhydrophilicity/underwater superoleophobicity under CO2/N2 stimulation. The membrane can be applied to various oil/water systems, including immiscible mixtures, surfactant-stabilized emulsions, multiphase emulsions and pollutant-containing emulsions, demonstrating high separation efficiency (>99.9%), recyclability, and self-cleaning performance. Due to robust separation properties coupled with the excellent scalability, the membrane shows great implications for smart liquid separation.

The effect of group IIIA metal ion dopants on the photocatalytic activities of nanocrystalline Sr0.25H1.5Ta2O6·H2O.

A series of group IIIA metal ion electron acceptors doped into Sr(0.25)H(1.5)Ta(2)O(6)·H(2)O (HST) samples have been prepared by an impregnation and calcination method for the first time. The samples are characterized by XRD, TEM, DRS and XPS. The variations in the electronic structure and photoelectric response after metal ion doping are investigated by theoretical calculations and photocurrent experiments, respectively. Results show that the metal ions can be efficiently incorporated into the HST crystal structure, which is reflected in the lattice contraction. Meanwhile, the photoabsorption edges of the metal-doped HST samples are red shifted to a longer wavelength. Taking into account the ionic radii and electronegativities of the dopants, as well as the XRD and XPS results, it is concluded that Ta(5+) ions may be partially substituted by the Al(3+) and Ga(3+) ions in the framework, while In(3+) ions are the favourable substitutes for Sr(2+) sites in the cavity. The first-principles DFT calculations confirm that the variation of the band structure is sensitive to the type of group IIIA metal ion. Introducing the dopant only at the Ta site induces an obvious variation in the band structure and the band gap becomes narrow. Meanwhile, an ''extra step'' appeared in the band gap, which can trap photogenerated electrons from the valance band (VB) and could enhance the charge mobility and the photocurrent. For the photocatalytic degradation of methyl orange in an aqueous solution and in benzene in the gas phase, the doped samples show superior photocatalytic activities compared with both undoped samples and TiO(2). The enhanced photocatalytic activities can be well explained by their electronic structure, photoabsorption performance, photoelectric response, and the concentration of the active species. Due to the fact that Ga ion doping can create an acceptor impurity level and change the electronic band, efficiently narrowing the band gap, the Ga-doped sample shows the highest photocatalytic activity.

Liproxstatin­1 induces cell cycle arrest, apoptosis, and caspase­3/GSDME­dependent secondary pyroptosis in K562 cells.

Leukemia is a fatal hematopoietic disorder with a poor prognosis. Drug resistance is inevitable after the long­term use of chemotherapeutic agents. Liproxstatin­1, commonly known as a ferroptosis inhibitor, has never been reported to have anticancer effects. In the present study, the antileukemic role of liproxstatin­1 in K562 leukemia cells was investigated. Liproxstatin­1 inhibited K562 cell proliferation in a dose­ and time­dependent manner. RNA sequencing revealed several pathways that were affected by liproxstatin­1, such as the G1/S transition of the mitotic cell cycle and extrinsic or intrinsic apoptotic signaling pathways. The results of flow cytometry indicated that liproxstatin­1 arrests the cell cycle at the G1 phase, and even at the G2/M phase. p21WAF1/CIP1, a cyclin­dependent kinase inhibitor, was upregulated. It was also determined that liproxstatin­1 induced BAX and TNF­α expression, which was accompanied by cleavage of caspase­3 and PARP. The caspase­3­specific inhibitor z­DEVD­FMK rescued some of the apoptotic cells. Interestingly, K562 cells were characterized by swelling and plasma membrane rupture when treated with a high concentration of liproxstatin­1, which was inconsistent with the typical apoptotic appearance. Thus, it was hypothesized that apoptosis­mediated pyroptosis occurs during liproxstatin­1­induced cell death. The expression of the hallmark of pyroptosis, the cleaved N­terminal GSDME, increased. Additionally, it was observed that endoplasmic reticulum stress and autophagy were involved in liproxstatin­1­induced cell death. Collectively, liproxstatin­1 induced cell cycle arrest, apoptosis, and caspase­3/GSDME­dependent secondary pyroptosis in K562 leukemia cells, which provides new hope for the treatment of leukemia.

Engineering of crystal phase over porous MnO2 with 3D morphology for highly efficient elimination of H2S.

In the present work, we report a facile oxalate-derived hydrothermal method to fabricate α-, ß- and δ-MnO2 catalysts with hierarchically porous structure and study the phase-dependent behavior for selective oxidation of H2S over MnO2 catalysts. It was disclosed that the oxygen vacancy, reducibility and acid property of MnO2 are essentially determined by the crystalline phase. Systematic experiments demonstrate that δ-MnO2 is superior in active oxygen species, activation energy and H2S adsorption capacity among the prepared catalysts. As a consequence, δ-MnO2 nanosphere with a hierarchically porous structure shows high activity and stability with almost 100% H2S conversion and sulfur selectivity at 210 °C, better than majority of reported Mn-based materials. Meanwhile, hierarchically porous structure of δ-MnO2 nanosphere alleviates the generation of by-product SO2 and sulfate, promoting the adoptability of Mn-based catalysts in industrial applications.