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Dual-atom site catalysts with the adjacent metal atomic sites can cooperatively catalyze oxygen reduction reaction (ORR), showing great potential in ORR field. Herein, the ORR activity and mechanism of a supported metal dual-atom site catalyst M2-DAC (M is 3d transition metal) is explored thoroughly by density functional theory methods. By calculating Ed of M2-DAC, all structures are thermodynamically stable and are used for subsequent studies. Considering the adsorption of O2, total 6 kinds of M2-DAC are identified as potential candidate materials for catalyzing ORR due to their moderate adsorption of O2. The binding energy of ORR species and the change of Gibbs free energy in each step of ORR are calculated, and Co2-DAC exhibits notable catalytic activity (ηORR = 0.39 V). Moreover, the charge analysis of Co2-DAC shows that the ORR activity of the catalyst mainly comes from the metal atom and the O atoms coordinated with the metal atoms. [ABSTRACT FROM AUTHOR]

It is challenging to fabricate supported Ni catalysts with more active sites to improve their low-temperature catalytic performance in CO 2 methanation. Herein, firstly, ultrathin (∼4 nm) NiZrAl layered double hydroxide (LDH) nanosheets were synthesized by co-precipitation method, followed by aqueous miscible organic solvent treatment (AMOST), and applied as catalyst precursors for CO 2 methanation. After H 2 reduction, the surface area of Ni particles in NiZrAl-LDH-AMO-R was significantly higher than that of NiZrAl-LDH-R without AMOST. As a result, the NiZrAl-LDH-AMO-R showed higher catalytic activity than NiZrAl-LDH-R owing to its higher H 2 and CO 2 chemisorption capacity and lower activation energy. During the 100 h-lifetime test, NiZrAl-LDH-AMO-R maintained a steady CO 2 conversion of about 92.3%. Moreover, NiZrAl-LDH-AMO-R maintained its catalytic activity after a 600 °C-hydrothermal treatment, suggesting its high stability. In situ DRIFTS results reveal that CO 2 methanation on both NiZrAl-LDH-R and NiZrAl-LDH-AMO-R followed the HCOO∗ route. Interestingly, more active sites obtained after AMOST strongly promoted the generation and decomposition of HCOO∗, and thus significantly improved the activity of NiZrAl-LDH-AMO-R at low temperatures. Ni catalyst derives from the ultrathin NiZrAl-AMO-LDH nanosheets precursor shows remarkably improved low-temperature catalytic performance in CO 2 methanation via the HCOO∗ pathway. This is because the exfoliation of LDH by aqueous miscible organic solvents (AMOST) exposes more Ni active sites, which significantly promote the formation of HCOO∗ from CO 2. [Display omitted] • NiZrAl-LDH-AMO ultrathin nanosheets were facilely prepared. • NiZrAl-LDH-AMO-R catalyst has more active sites. • NiZrAl-LDH-AMO-R catalyst shows high stability for CO 2 methanation. • NiZrAl-LDH-AMO-R can maintain catalytic activity after 5 h-hydrothermal treatment. [ABSTRACT FROM AUTHOR]

A convenient and efficient β-cyclodextrin-SO3H-assisted strategy for construction of spiro indoline derivatives in aqueous media was disclosed. The present protocol showed various advantages including short reaction time, broad scope of substituents, simplicity of practice, high yields of products, recyclability of catalysts, safety, and cheapness of benign solvents. Preliminary study indicated that some of spiroindoline derivatives exhibited anti-Tobacco Mosaic Virus (TMV) activity for potential use in plant protection. [ABSTRACT FROM AUTHOR]

There is no doubt that hydrogen energy can play significant role in promoting the development and progress of modern society. The utilization of hydrogen energy has developed rapidly, but it is far from the requirement of human. Therefore, it is very urgent to develop methodologies and technologies for efficient hydrogen production, especially high activity and durable electrocatalysts. Here a bimetallic oxide cluster on heterostructure of vanadium ruthenium oxides/graphdiyne (VRuOx/GDY) is reported. The unique acetylene‐rich structure of graphdiyne achieves outstanding characteristics of electrocatalyst: i) controlled preparation of catalysts for achieving multiple‐metal clusters; ii) regulation of catalyst composition and morphology for synthesizing high‐performance catalysts; iii) highly active and durable hydrogen evolution reaction (HER) properties. The optimal porous electrocatalyst (VRu0.027Ox/GDY) can deliver 10 mA cm−2 at low overpotentials of 13 and 12 mV together with robust long‐term stability in alkaline and neutral media, respectively, which are much smaller than Pt/C. The results reveal that the synergism of different components can efficiently facilitate the electron/mass transport properties, reduce the energy barrier, and increase the active site number for high catalytic performances. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) have serious hazard to human health and ecological environment. Due to its low cost and high activity, the catalytic oxidation technology considered to be the most effective method to remove VOCs. Toluene is one of the typical VOCs, hence its catalytic elimination is crucial for the regulation of VOCs. Manganese dioxide (MnO 2) has been extensively studied for its excellent redox performance and low-temperature operation conditions. In this review, we summarize the research progresses in the toluene catalytic oxidation of MnO 2 -based catalysts, which contain single MnO 2 , metal-doped MnO 2 and supported MnO 2 catalyst. In particular, we pay much attention on the relationship between the chemical properties and toluene oxidation performance over MnO 2 catalyst, as well as the catalytic reaction mechanisms. Moreover, the effects of different crystal forms and morphologies on the catalytic toluene reaction were discussed. And the perspective on MnO 2 catalysts for the catalytic oxidation of toluene has been proposed. We expect that the summary of these important findings can serve as an important reference for the catalytic treatment of VOCs. To better understand the fundamental relation between different aspects of MnO 2 -based catalysts in the field of toluene catalytic oxidation, this review mainly addresses the catalyst development, key influential factors and reaction mechanism of toluene decomposition in the catalysis process. Also, a comparison of the performance in various MnO 2 -based catalysts is provided, including single MnO 2 , metal-doped MnO 2 and supported MnO 2 catalyst. Particular emphasis is given to the importance of the catalyst poisoning and by-product detection in the toluene removal, which can be used as a reference point for future studies in this field. [Display omitted] • Systematically reviews the emerging advances of catalytic toluene on MnO 2. • The influence of various factors (crystal and morphology) were fully discussed. • Exploring the reaction path and mechanism via in-situ techniques. • Future perspectives on catalytic toluene was proposed. [ABSTRACT FROM AUTHOR]

Benefiting from the construction of lamellar framework Sm-CeZrTiAl amorphous mixed oxides synthesized by the hydrothermal method, enhanced NH 3 -SCR performance over a wide temperature window for K poisoning resistance was observed. The Sm-CeZrTiAl catalyst preserved higher catalytic performance after K was introduced than the catalysts without added Sm, as it maintained > 90% NO conversion between 300 and 420 °C. The outstanding K poisoning-resistance of the Sm-CeZrTiAl catalyst could benefit from its good nano-Al 2 O 3 flake skeleton structure, high specific surface area, and rich pore channels. In addition, Sm doping can effectively increase the number of surface acid sites, especially strong acid sites, which promote the formation of NOx adsorption species such as nitrite, bidentate nitrate and bridging nitrate intermediates and facilitate the conversion of NO to N 2 by following the Langmuir-Hinshelwood mechanism. In addition, the synergy between Sm/La and Ce leads to more Ce3+ and Brønsted acid sites. Through the redox cycle of Ce4++Sm2+→Ce3++Sm3+ or Ce4++La2+→Ce3++La3+, catalytic reduction can be realized with good performance. Moreover, a significant portion of K on the catalyst surface preferentially interacted with strong acidic sites provided by Sm/La doping, thereby preventing Ce species from poisoning and leaving them available for the catalytic cycle. [Display omitted] • Sm or La is a critical additive for CeZrTiAl catalyst to alleviate K poisoning. • The acidity and redox are well preserved due to the synergism of Sm and Ce. • The Sm doping led to more Ce3+ species and chemisorbed oxygen species. • The Ce species are protected due to K atom preferentially interacted with Sm. [ABSTRACT FROM AUTHOR]

Cake-like MnO 2 @CeO 2 catalyst with hierarchical nanosheets structure has been successfully constructed by in situ methods. The relationship between structure and activity of the MnO 2 @CeO 2 catalyst was characterized using various analytical techniques. It is identified that rich surface oxygen species and better reducibility were generated due to the strong synergistic effect between MnO 2 and CeO 2 , and hence nearly T 90 toluene conversion can be obtained for the 10%-MnO 2 @CeO 2 catalyst under 240–300 °C. In addition, it is found that after loading MnO 2 on the multi-layer CeO 2 support to form a hierarchical cake-like structure, the oxygen vacancies, Ce3+/Ce4+ and BET surface area of MnO 2 @CeO 2 increased significantly, which is beneficial to toluene adsorption and reaction. Furthermore, the in situ DRIFTS study demonstrated that the lattice oxygen and surface oxygen both participate in the toluene oxidation, whereas surface active oxygens adsorbed on the oxygen vacancies will lead to deep oxidation by forming abundance intermediates. Cake-like MnO 2 @CeO 2 catalyst with a hierarchical nanosheets structure have been successfully constructed by in situ method, which exhibit excellent catalytic activity toluene oxidation. High BET surface area, more oxygen vacancies, rich surface oxygen species and better reducibility were generated due to the strong synergistic effect between MnO 2 and CeO 2. [Display omitted] • Cake-like MnO 2 @CeO 2 with nanosheets structure were successfully constructed. • 10%-MnO 2 @CeO 2 catalyst exhibits excellent toluene oxidation activity. • More oxygen vacancies are generated due to the synergistic effect of structure. • Oxygen species adsorbed on oxygen vacancies leads to deep oxidation of toluene. [ABSTRACT FROM AUTHOR]

A series of Fe-SO 4 /TiO 2 catalysts were synthesized by simple impregnation method, and their performances of the selective catalytic reduction (SCR) of NO x by NH 3 were measured. Fe 2 (SO 4) 3 with the largest specific surface area exhibited the best high-temperature performance, Fe(OH)SO 4 with the highest content of chemisorbed oxygen species and the lowest initial reduction temperature illustrated the best low-temperature activity, and FeSO 4 presented the worst overall activity. Meanwhile, the sulfur tolerance and structure-activity relationship of Fe-SO 4 /TiO 2 catalysts were systematically studied. Further, the active components in Fe-SO 4 /TiO 2 catalysts were tested to be FeSO 4 , Fe 2 (SO 4) 3 and Fe(OH)SO 4. And the optimum performance (light-off temperature at around 200 °C, NO conversion over 80% within 280–400 °C) was obtained with 20 wt% FeSO 4 loading. Remarkably, 20%Fe-SO 4 /TiO 2 catalyst was found to possess excellent sulfur tolerance due to the increased surface acidity and chemisorbed oxygen species by SO 2 sulfation. In situ DRIFTs demonstrated that there were certain NH 3 and NO adsorption sites on the surface of 20%Fe-SO 4 /TiO 2 catalyst, on which the NH 3 -SCR reactions occurred mainly followed Langmuir-Hinshelwood (L-H) mechanism accompanied by a slight Eley-Rideal (E-R) mechanism. [Display omitted] Fe-SO 4 /TiO 2 catalysts whose active ingredients were FeSO 4 , Fe 2 (SO 4) 3 and Fe(OH)SO 4 demonstrated excellent sulfur tolerance, since SO 2 sulfation and Fe-based sulfates facilitate the formation of the stronger surface acidity and more chemisorbed oxygen species. • SCR activity order of iron sulfates: Fe(OH)SO 4 > Fe 2 (SO 4) 3 > FeSO 4. • Fe-SO 4 /TiO 2 catalysts exhibited excellent sulfur tolerance. • Acidity and chemisorbed oxygen increased due to sulfation enhancement by SO 2. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni-based catalysts are obtained by reduction of the Ni-Zr-Al-LDHs. • Introduction of Zr species produces more basic sites and oxygen vacancies. • Synergetic effect between Ni and ZrO 2 account for excellent low-temperature activity. • ZrO 2 helps to enhance the CO 2 adsorption. • CO 2 methanation produces CH 4 via the intermediate formate route. Developing Ni-based catalysts with high activity and stability in low-temperature methanation is necessary due to their sintering and coking at high temperatures. Here, we report our developed novel Ni-Zr-Al catalysts derived from Ni-Zr-Al ternary hydrotalcites synthesized by a hydrothermal process, followed by a reduction in hydrogen. Comparing with the Ni-Al catalyst derived from Ni-Al hydrotalcite and the commercial Ni-based catalyst, the Ni-Zr-Al catalysts show a remarkably higher low-temperature activity (210−270 °C) in CO 2 methanation. Both the experimental and theoretical calculations confirmed the introduction of Zr into the Ni-Al binary hydrotalcite could generate synergetic effects between Ni and ZrO 2 , resulting in more surface oxygen vacancies, basic sites, and abundant mesopores. In-situ DRIFTS analysis showed the CO 2 methanation to CH 4 follows the intermediate formate route. This work provides a new theoretical understanding of CO 2 activation and methanation, and a practical way to address the existing problem for Ni-based catalysts. [ABSTRACT FROM AUTHOR]

Keywords: graphdiyne; heterostructures; iridium oxides; oxygen evolution reaction; quantum dots EN graphdiyne heterostructures iridium oxides oxygen evolution reaction quantum dots 1 1 1 08/28/21 20210826 NES 210826 B Quantum Dots b In article number 2101138, Yurui Xue, Feng He, Yuliang Li and co-workers demonstrate controllable growth of iridium oxide quantum dots by exploiting the unique properties of graphdiyne. Graphdiyne, heterostructures, iridium oxides, oxygen evolution reaction, quantum dots This provides an ideal system to control the preparation of small size, quantum dot catalysts, fully demonstrating the size and quantum effects of these catalysts in the catalytic process, and obtaining highly active and robust catalysts with excellent acidic water oxidation performance. [Extracted from the article]

Superior CuY catalysts exhibited near total NO removal within 180–300 °C and no SO 2 toxicity <180 °C and >240 °C. [Display omitted] • A superior CuY catalysts for NO removal by one-step alkaline ion-exchange method. • NO conversion near 100 % within 180–300 °C, no SO 2 toxicity < 180 °C and > 240 °C. • Isolated Cu2+ play the key role in promoting NH 3 -SCR activities. • Temperature dependence of reaction mechanisms and SO 2 tolerance are revealed by various methods. • Different occupancy of NH 3 (α cage) and SO 2 (β cage) and catalytic decomposition of (NH 4) 2 SO 4 for SO 2 tolerance. CuY catalysts prepared by one-step alkaline ion exchange method with isolated Cu2+ as active species were studied for NO removal with NH 3 -SCR, which achieved nearly 100 % of NO removal within 180–300 °C. An interesting trend in NH 3 -SCR activity of CuY catalysts was found that there was abrupt changes around 150 °C. In low-temperature range (<150 °C), SCR reactions on CuY catalyst should mostly obey Eley-Rideal ("E-R") mechanism with Brønsted acid sites mainly involved and NH 4 + are critical intermediate species. In high-temperature range (>150 °C), SCR reactions take place mainly according to "E-R" mechanisms with Lewis acid sites, coordinated NH 3 and nitrate species mainly involved, and Langmuir-Hinshelwood mechanism ("L-H") could also happen. Furthermore, CuY catalyst could catalyze the decomposition of ammonium sulfates species. And EPR tests and theoretical calculations demonstrated that the differences between adsorption preference of NH 3 (mostly in α cage) and SO 2 (mostly in β cage) also offer a fundamental pathway for SO 2 resistance. Thus, CuY catalysts exhibited excellent SO 2 resistance with almost no toxicity on NO removal particularly at low temperatures (<180 °C) and high temperatures (>240 °C). [ABSTRACT FROM AUTHOR]

The oxygen reduction reaction (ORR) is essential for both energy conversion devices and green hydrogen peroxide (H 2 O 2) synthesis. Whereas, it remains a challenge to efficiently tune the oxygen reduction selectivity toward the target applications. Herein, we designed two kinds of Co-N-C materials with encapsulated Co nanoparticles (Co NP -N-C) and with atomically dispersed cobalt atoms strongly embedded into nitrogen-doped carbon nanotubes (Co SA -N-CNTs), and successfully realized the ORR pathway transformation from four-electron (4e−) to two-electron (2e−) for high-performance H 2 O 2 production. This tunability is ascribed to the modification of the atomic configuration of the Co-N-C catalyst. Remarkably, when employing Co SA -N-CNTs material as a 2e− ORR catalyst, the assembled electrode exhibits a high H 2 O 2 production rate of approximately 974 ± 25 mmol g cat −1 h−1, along with an ultra-fast organic matter degradation performance. This work provides an efficient strategy for tuning oxygen reduction selectivity via a simple structure tuning of the materials for specific applications. Co SA -N-CNTs catalyst with atomically dispersed Co−N x sites was constructed by tuning the structure and atomic configuration, which realized the oxygen reduction reaction from the dominant 4e− pathway to the 2e− pathway. The catalyst exhibits a high H 2 O 2 production rate and ultrafast organics degradation performance. [Display omitted] • Atomically dispersed Co atoms strongly embedded into N-doped CNTs were fabricated. • Co SA -N-CNTs exhibited superior H 2 O 2 production in acidic media. • Co SA -N-CNTs delivered good application in the degradation of pollutants field. [ABSTRACT FROM AUTHOR]

Exploring the high-efficient two-electron oxygen reduction reaction (2e– ORR) catalysts is greatly significant for promoting hydrogen peroxide (H 2 O 2) electroproduction. Herein, we have constructed a pyranoid-O-dominated graphene-like nanocarbon (GLC) material with high surface area, hierarchical porous structure, and abundant edge defects, through the high-temperature alkali activation of cellulose-based precursor. Benefiting from its integrated merits, the GLC electrocatalyst exhibits excellent 2e– ORR performance with high H 2 O 2 productivity and ultrafast wastewater degradation ability. Interestingly, whether changing the carbonaceous precursor or alkali activator, all the as-prepared pyranoid-O-dominated GLC-based materials display high 2e– selectivity for the ORR. Based on further analogical experiments and theoretical analysis, the results reveal that the nature of 2e– selectivity on carbon-based materials is highly associated with the pyranoid-O dopants, rather than the surface oxygen-containing functional groups declared by the previous reports. These findings may bring new insight into the 2e– ORR selectivity of carbon-based electrocatalysts for H 2 O 2 production. [Display omitted] • A pyranoid-O-dominated graphene-like nanocarbon (GLC) was constructed. • High H 2 O 2 productivity and wastewater degradation rate were achieved. • A new principle for the 2e– ORR selectivity of carbon-based catalysts was proposed. [ABSTRACT FROM AUTHOR]