ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
·
2022
·Vol. 61
·期 18
·e202117201
·
IF 16.823
Jiaqi Si,Guofeng Zhao,Weidong Sun,Jincun Liu,Cairu Guan,Yong Yang,Xue-Rong Shi,Yong Lu
Graphical For the oxidative coupling of methane (OCM) reaction, the MnO x -Na 2 WO 4 /SiO 2 catalyst enriched with Q 2 units in the SiO 2 carrier achieves 23 % CH 4 conversion and 72 % C 2–3 selectivity at 660 °C. A large number of Q 2 units in MnO x -Na 2 WO 4 /SiO 2 is a trigger for markedly lowering the light-off temperature of the Mn 3+ ↔Mn 2+ redox cycle because of the easy formation of MnSiO 3 . Oxidative coupling of methane (OCM) catalyzed by MnO x -Na 2 WO 4 /SiO 2 has great industrial promise to convert methane directly to C 2–3 products, but its high light-off temperature is the most challenging obstacle to commercialization and its working mechanism is still a mystery. We report the discovery of a low-temperature active and selective MnO x -Na 2 WO 4 /SiO 2 catalyst enriched with Q 2 units in the SiO 2 carrier, being capable of converting 23 % CH 4 with 72 % C 2–3 selectivity at 660 °C. From experiments and theoretical calculations, a large number of Q 2 units in the MnO x -Na 2 WO 4 /SiO 2 catalyst is a trigger for markedly lowering the light-off temperature of the Mn 3+ ↔Mn 2+ redox cycle involved in the OCM reaction because of the easy formation of MnSiO 3 . Notably, the MnSiO 3 formation proceeds merely through the SiO 2 -involved reaction in the presence of Na 2 WO 4 : Mn 7 SiO 12 +6 SiO 2 ↔7 MnSiO 3 +1.5 O 2 . The Na 2 WO 4 not only drives the light-off of this cycle but also gets it working with substantial selectivity toward C 2–3 products. Our findings shine a light on the rational design of more advanced MnO x -Na 2 WO 4 based OCM catalysts through establishing new Mn 3+ ↔Mn 2+ redox cycles with lowered light-off temperature.
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CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Lu Zhang,Meng Zhang,Xiaozhe Song,Hui Wang,Zhaoyong Bian
Here, we report enhancement of the photoelectrochemical (PEC) performance of MnO x /graphite-like carbon nitride (g-C 3 N 4 ) nanocomposites synthesized by one-step thermal decomposition for degradation of clofibric acid (CA). MnO x showed enhanced broadband ultraviolet–visible light regions, efficient charge generation–separation, and enhanced PEC performance when combined with g-C 3 N 4 . Photogenerated holes can be efficiently captured by introducing Mn 2+ /Mn 3+ /Mn 4+ valence band transitions. In addition to a good visible-light response, the MnO x /g-C 3 N 4 -10 (g-C 3 N 4 with 10% Mn(NO 3 ) 2 ·6H 2 O) photoanode showed enhanced photocurrent density of 0.03 × 10 −3 A cm −2 at 0.63 V vs. Ag/AgCl, which was approximately 100 times that of pristine g-C 3 N 4 . The superoxide radical and positive holes played dominant roles in PEC degradation of CA. The MnO x /g-C 3 N 4 -10 photoanode showed the highest photoelectrocatalytic performance under acidic conditions because of electrostatic attraction between the electrode and CA. The CA degradation ratio using the MnO x /g-C 3 N 4 -10 photoanode was 100% under visible light in 6 h at pH = 3. This work provides a simple and sustainable strategy to modify g-C 3 N 4 for captured holes to improve PEC degradation of CA, and it is promising for application to different materials in a variety of fields.
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Catalysts
·
2020
·Vol. 10
·期 6
·681
·
IF 3.52
Qian Zhang,Yiwen Jiang,Jingheng Gao,Mingli Fu,Sibei Zou,Yanxia Li,Daiqi Ye
A series of CeO2–MnOXcatalysts with different Ce contents was prepared using Mn–BTC MOF as a sacrificial template for toluene oxidation. Interestingly, the performance of CeO2–MnOXincreased rapidly only when the Ce content lower than 5%. The 1%-, 3%- and 10%-Ce-content samples exhibited the T90value of 325 °C, 291 °C and 277 °C, respectively. XRD shows that the catalyst phase changes significantly before (Mn3O4only) and after (Mn2O3, Mn3O4and CeO2) 3% Ce loading. All other results indicated that the Ce–Mn interface properties of different Ce content composite oxides was quite distinguishable in terms of removal and energy efficiency. XRD and XPS results further showed that there a Ce monolayer dispersion threshold existed on the interface of MnOX(3.2 wt%, confirmed by XPS), which caused the difference in performance increment. The dispersed Ce could be divided into a monolayer dispersion state (1–3%) and a crystalline phase state (>3%), according to the existence form, which corresponded to the significant and minor enhancements of toluene conversion rate. Importantly, the Ce in monolayer dispersion state obviously improved the redox properties of catalysts interface, while the Ce in crystal state not. The interfaces with monolayer dispersion Ce result in more abundant metal ion states, oxygen vacancies, better electron transfer performance and catalytic activity.
研究领域:
催化化学
·
材料科学
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CHEMOSPHERE
·
2021
·
IF 7.086
Ziyang Xu,Shengpeng Mo,Yanxia Li,Yuchen Zhang,Junliang Wu,Mingli Fu,Xiaojun Niu,Yun Hu,Daiqi Ye
The problem of deep oxidation of low concentrations of VOCs in industrial tail gas is exceptionally urgent. The preparation of VOCs ozonation catalyst with a high mineralization rate is still a challenge. In this paper, manganese oxide carriers with different morphologies were synthesized by simple methods and used to catalyze ozone mineralization of toluene after loading Pt nanoparticles efficiently. The conversion of toluene over Pt/MnO x -T catalyst was more than 98 % at ambient temperature, and the mineralization rate of toluene was close to 100 % at 70 °C. Through a variety of characterization methods, the strong metal-support interaction (SMSI) between Pt nanoparticles and carriers was successfully constructed. It was found that SMSI successfully optimized the surface oxygen species and oxygen migration ability of the catalyst, and then realized the high degree of mineralization of toluene at low temperature. This paper guides the subsequent development of Pt–Mn catalysts for catalytic organic pollutants ozonation with high activity.
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Advanced Science
·
2026
·
IF 14.1
Benzhi Wang,Ziyang Duan,Jeong Yeon Heo,Thu Ha Le,Byunggon Song,Sunhyeong Kwon,Ji Hoon Lee,Jonghwan Suhr,Hyung Mo Jeong
Electrocatalytic water splitting offers an efficient pathway for producing renewable hydrogen, which is considered a key strategy toward global carbon neutrality. Yet, under harsh industrial operating conditions, the catalyst inevitably undergoes dynamic structural reconstruction, oxidative dissolution of active sites, and mechanical detachment during high-potential anodic oxygen evolution reaction (OER), severely limiting their activity and stability. Here, we present an MnO x (composed of Mn 3 O 4 and Mn 2 O 3 ) layer on the FeCoNiCrMn high-entropy alloy (HEA) surface (denoted as HEA-ML) via laser powder bed fusion (LPBF) process and reveal that the MnO x layer suppresses multimetal dissolution in HEA and mitigates excessive surface reconstruction under OER conditions. Furthermore, the MnO x layer featuring a porous and rough surface enhances water adsorption and bubble diffusion, thereby accelerating interfacial mass transfer and OER kinetics. These outstanding features endow the catalyst to exhibit both excellent activity (227 ± 2 mV at 10 mA cm −2 ) and industrial-grade ultra-stable OER performance (operating stably for 1500 h at 1.0 A cm −2 ). Our research findings provide new insights into the structure-activity-stability relationship of HEA electrocatalysts and demonstrate a novel approach for designing industrially viable OER catalysts with high activity and ultra-stability.
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Nature Communications
·
2026
·
IF 18.1
Zhao Yongqi,Wang Pu,Jiang Junjie,Zhao Ziwei,Xiu Aorui,Liu Xiaolong,Zhu Tingyu
Transition-metal oxides offer a low-cost alternative to precious metals for environmental catalysis, yet CO oxidation under humid and sulfur-laden conditions remains challenging due to rapid poisoning. Herein, we report an atomic dispersion of Ti‑decorated MnO x -Fe 2 O 3 catalyst that achieves high activity and remarkable H 2 O/SO 2 resistance. Atomically dispersed Ti provides electron-accepting 3d states from O 2p orbitals, which redistributes and stabilizes selected O 2p states while modifying their hybridization with neighboring Mn/Fe 3d orbitals. The localized electronic restructuring strengthens CO adsorption and facilitates lattice oxygen activation via a Mars-van Krevelen (MvK)-like mechanism, lowering the apparent activation energy to 64.59 kJ/mol. Simultaneously, Ti-O-Fe interfaces weaken SO 2 adsorption (from −1.96 eV to −0.19 eV) and suppress H 2 O competition, retaining >55% CO conversion under 10 vol% H 2 O and 10 ppm SO 2 , far surpassing the parent oxide (<10%). The orbital tuning strategy enables scalable poison resistant catalysts for industrial emission control, reducing reliance on precious‑metal systems.
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APPLIED CATALYSIS A-GENERAL
·
2022
·
IF 5.723
Lin-Cong He,Xu-Fang Wang,Chu-Feng Liu,Bei Li,Meng-Fei Luo,Jian Chen
An efficient MnO x /CeO 2 /ZSM-5 catalyst was developed for selective oxidation of diethylamine (DEA) with high N 2 selectivity in a wide temperature window ( Δ T = 140 °C), owing to the existence of oxidation and selective catalytic reduction (SCR) active sites. MnO x species prefer to locate on the surface of CeO 2 compared to ZSM-5, and the presence of CeO 2 is beneficial to form more Mn 4+ species, the active sites for oxidation reaction. The mechanistic investigation suggests that internal SCR of NO x generated from the over-oxidized DEA is the crucial pathway for N 2 generation. The high SCR activity of the MnO x /CeO 2 /ZSM-5 catalyst in oxidation conditions is mainly attributed to the synergistic catalysis of Mn 4+ species and acid sites of ZSM-5, the active sites for SCR reaction. Thus, it has been clearly clarified that addition of CeO 2 and its addition sequence could modulate the surface active sites of MnO x /ZSM-5 catalyst for the selective catalytic oxidation of DEA.
研究领域:
环境科学
·
催化化学
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Huayu Wu,Rongguan Lv,Rui Wang,Zhiyuan Zhao,Yuzhen Sun,Yu Liu,Yingna Chang,Jindi Wang,Kefan Song,Ming Chen,Rong Xing
3D Porous MnO x /rGO hydrogel (3DP MnO x /rGO hydrogel) as cathode material for aqueous zinc ion batteries (AZIBs) is synthesized by polyvinyl alcohol (PVA), nanowires of MnO x (NW MnO x ) and reduced graphene oxide (rGO) via repeated freeze-thaw method, which has a high flexibility and puncture resistance. The 3D self-supporting hydrogel presented complex 3D cross-linking system and excellent flexibility through hydrogen bonding and reinforcement of inorganic nano wires. The electrochemical and mechanical properties of the 3DP MnO x /rGO hydrogel are optimized by adjusting the respective percentages of NW MnO x (30%), rGO (5%), PVA (25%), and H 2 O (40%) in the total mass. The flexible hydrogel cathode exhibits a high capacity of 297.6 mA h g −1 and good cyclic stability after 500 cycles at 1 A g −1 . Finite element method confirms that the hydrogel material can alleviate the stress distribution caused by zincification process. The soft-packaged AZIBs, which utilize 3DP MnO x /rGO hydrogel as the cathode and Zn foil as the anode, exhibit excellent cycling performance (152.2 mA h g −1 at 1 A g −1 after 500 cycles under an angle of 180°) and provide a stable power supply across different bending angles.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·
IF 7.139
Rui Yu,Ying-Xia Du,Heng-Fan Zhao,Fei-Fei Cao,Wang-Ting Lu,Geng Zhang
The electrochemical water splitting in alkaline media is troubled by the lack of efficient electrocatalysts for hydrogen evolution reaction (HER). Herein, a crystalline/amorphous CoP/MnO x heterostructure is converted from a single-phase bimetallic Co–Mn oxide by phase separation strategy. The CoP/MnO x heterostructure only requires an overpotential of 135 mV to reach 10 mA cm −2 in 1 M KOH, which is lower than that of CoP (184 mV). The interface effect between CoP and MnO x is beneficial to the improvement of HER activity, which is confirmed by means of selective etching of MnO x and infrared spectroscopy . Moreover, the crystal size of CoP phase in the heterostructure is lower than that of the mono-component CoP. Furthermore, the decrease of precursor crystal size will give rise to a decrease in the CoP crystal size of heterostructure. The decline of crystal size results in higher active surface area and greater number of interfaces.
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Molecular Catalysis
·
2022
·
IF 5.089
Yiqing Zeng,Fengye Lyu,Yanan Wang,Shule Zhang,Qin Zhong,Zhaoxiang Zhong
High N 2 O selectivity of MnO x -TiO 2 catalyst hinders its development in ammonia selective catalytic reduction (NH 3 -SCR) of NO x . Herein, a series of MnO x -TiO 2 catalyst with different Mn/Ti ratio were prepared by wet-impregnation method to study the N 2 O formation during ammonia selective catalytic reduction (NH 3 -SCR) of NO x from the perspective of catalyst. It is found that MnO x and TiO 2 species are the mainly redox and acid sites for the NH 3 -SCR denitration reaction over MnO x -TiO 2 catalyst, respectively. As the Mn/Ti ratio increases, MnO x species layer expanded on TiO 2 support, leading to increase of redox sites but decrease of surface acid sites. These changes contribute to the occurrence of the no-selective oxidation of NH 3 on MnO x species and the over-activation of NH 3 at Mn-Ti interface, resulting in the formation of N 2 O via the route of 2NH 3 + 2O 2 → N 2 O + 3H 2 O and 4NO + 4NH 3 + 3O 2 → 4N 2 O + 6H 2 O, respectively. Through this work, it can be speculated that both improving MnO x dispersion and increasing surface acidity of catalyst are feasible strategy for suppressing the N 2 O formation on MnO x -TiO 2 .
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 29
·期 53
·80399-80410
·
IF 5.19
Shu Xinpeng,Bi Huaqi,Wang Jun,Yang Jiaxin,Wang Jue,Liu Guangqing,Su Bensheng
Catalytic ozonation with supported metal oxides is a promising strategy for addressing refractory pollutants in wastewater. In this study, γ-Al 2 O 3 supported MnO x -CeO x catalysts (MC 1 , MC 2 , and MC 3 ) obtained at different calcination temperatures (400 °C, 550 °C, and 700 °C) were applied as effective catalysts for ozonation and explored the feasibility of the treatment of oxytetracycline (OTC) wastewater. Comparatively, the MC 2 possessed the highest molar ratios of Mn 3+ /Mn 4+ (1.60) and Ce 3+ /Ce 4+ (0.96), the largest surface area (273.8 m 2 g −1 ) with a petal-shaped structure, and most abundant surface hydroxyls (3.78 mmol g −1 ). These physicochemical characteristics benefited the surface reaction and resulted in the acceleration of ozone decomposition, electron transfer, and •OH generation, thereby improving the catalyst’s adsorption ability and catalytic activity. The combination with MC 2 increased the OTC and COD removal of the ozonation process from 59.1% and 29.0% to 94.7% and 83.3% in 25 min, respectively. By employing electron paramagnetic resonance (EPR) and radical quenching experiments, it was verified that •OH species generation promoted the mineralization of OTC. The possible degradation pathways of OTC were investigated through mass spectrometry, and the route consisted of dehydration, deamination, and demethylation. Moreover, during a 12-day continuous experiment, MC 2 catalyst exhibited excellent reusability and catalytic stability, with COD removal efficiencies above 80%.
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Journal of Environmental Sciences
·
2015
·
IF 2.002
Lei Chen,Zhichun Si,Xiaodong Wu,Duan Weng,Zhenwei Wu
A MnO x –NbO x –CeO 2 catalyst for low temperature selective catalytic reduction (SCR) of NO x with NH 3 was prepared by a sol–gel method, and characterized by NH 3 –NO/NO 2 SCR catalytic activity , NO/NH 3 oxidation activity, NO x /NH 3 TPD , XRD , BET, H 2 -TPR and in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The results indicate that the MnO x –NbO x –CeO 2 catalyst shows excellent low temperature NH 3 -SCR activity in the temperature range of 150–300°C. Water vapor inhibits the low temperature activity of the catalyst in standard SCR due to the inhibition of NO x adsorption. As the NO 2 content increases in the feed, water vapor does not affect the activity in NO 2 SCR. Meanwhile, water vapor significantly enhances the N 2 selectivity of the fresh and the aged catalysts due to its inhibition of the decomposition of NH 4 NO 3 into N 2 O.
研究领域:
环境催化
·
大气污染控制
·
材料化学
·
表面科学
·
化学工程
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危险品化学品经营许可证（带存储）