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Solar‐to‐chemical energy conversion under weak solar irradiation is generally difficult to meet the heat demand of CO2 reduction. Herein, a new concentrated solar‐driven photothermal system coupling a dual‐metal single‐atom catalyst (DSAC) with adjacent Ni−N4 and Fe−N4 pair sites is designed for boosting gas‐solid CO2 reduction with H2O under simulated solar irradiation, even under ambient sunlight. As expected, the (Ni, Fe)−N−C DSAC exhibits a superior photothermal catalytic performance for CO2 reduction to CO (86.16 μmol g−1 h−1), CH4 (135.35 μmol g−1 h−1) and CH3OH (59.81 μmol g−1 h−1), which are equivalent to 1.70‐fold, 1.27‐fold and 1.23‐fold higher than those of the Fe−N−C catalyst, respectively. Based on theoretical simulations, the Fermi level and d‐band center of Fe atom is efficiently regulated in non‐interacting Ni and Fe dual‐atom pair sites with electronic interaction through electron orbital hybridization on (Ni, Fe)−N−C DSAC. Crucially, the distance between adjacent Ni and Fe atoms of the Ni−N−N−Fe configuration means that the additional Ni atom as a new active site contributes to the main *COOH and *HCO3 dissociation to optimize the corresponding energy barriers in the reaction process, leading to specific dual reaction pathways (COOH and HCO3 pathways) for solar‐driven photothermal CO2 reduction to initial CO production. [ABSTRACT FROM AUTHOR]

In this reported work, lotus leaves‐derived biochar (LBC) was modified using various chemical methods. LBC prepared by different modification methods was used as the carrier for the development of low‐temperature selective catalytic reduction (SCR) catalysts. A comparative study of low‐temperature SCR manganese catalysts based on LBC chemically modified using NaOH, HNO3 and hexadecylcetyltrimethylammonium bromide (CTAB) was performed, revealing different deNOx performance of these catalysts. For the supported catalysts, the 25%Mn/LBC‐OH catalyst appeared to be optimum since it exhibited over 95% NOx conversion at 225 °C with a space velocity of 37 500 h−1. The microstructure, phase composition, redox properties and surface acidity were determined using field emission scanning electron microscopy, Brunauer–Emmett–Teller surface area, X‐ray diffraction, H2‐temperature‐programmed reduction, NH3‐temperature‐programmed desorption, and so forth. The results showed that the excellent SCR performance of 25%Mn/LBC‐OH was closely related to its abundant high valence Mn, suitable surface acidity and high redox capability. More importantly, highly dispersed MnOx easily formed on the surface of the LBC‐OH support, which was the key factor in the excellent catalytic activity of 25%Mn/LBC‐OH catalyst. Furthermore, the highly dispersed 25%Mn/LBC‐OH catalyst also exhibited improved tolerance to SO2 and H2O, making this catalyst a good candidate for reducing the NOx emission from coal‐fired power plants. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

The Gd dopant with smaller ion radius and low valence state would generate more Gd-Ce complex and less GdO 8 -type complex, producing more oxygen vacancies than pure sample on ceria surface and subsurface. Due to higher content of surface oxygen vacancy, the catalyst exhibits better ability to adsorb and active gaseous oxygen, which would supply more active oxygen species for toluene oxidation. More than that, the Gd doping could also drive more electrons to transfer from support to metal. As a result, more Pt sites with high electronic density and low-coordinated would be obtained, effectively promoting the adsorption and dissociation ability of toluene molecule. Hence, combined both of the advantages, the doping of Gd would enhance the catalytic oxidation of toluene over Pt/CeO 2 catalyst. On the contrary, owing to the higher ion radius and existence of extra +4 state, the Pr dopant would form more PrO 8 -type complex and less Pr-Ce complex, generating less oxygen vacancies than pure sample. Furthermore, the lower concentration of oxygen vacancy is disadvantage to the formation of high electronic density and low-coordinated Pt sites, which exhibits a poor ability for toluene adsorption and dissociation. Therefore, both of the shortages are not conducive to catalytic reaction. [Display omitted] • The Pt/CeO 2 catalyst exhibit a lanthanide-doping-dependent catalytic activity toward toluene oxidation. • The chemical properties of oxygen vacancy on ceria could be modulated by doped of lanthanide with various ionic radius and valence state. • The electron density and coordination structure of metal is closely related to the oxygen vacancy concentration of support. • The incorporation of Gd significantly improve catalytic activity, and the catalyst shows well stability and vapor resistance. The present work was undertaken to know the lanthanide doping effect on the physicochemical properties of Pt/CeO 2 catalysts and their catalytic activity for toluene oxidation. A series of lanthanide ions (La, Pr, Nd, Sm and Gd) were incorporated into ceria lattice by hydrothermal method, and the Pt nanoparticles with equal quality were successfully loaded on various ceria-based supports. Their catalytic performance toward toluene oxidation shows a remarkable lanthanide-doping effect, and the activity is much dependent on the ion radius and valence state of dopants. Owing to smaller ion radius and low valence state, the dopant of Gd would form more Gd-Ce complex and less GdO 8 -type complex, generating more oxygen vacancies and then promoting oxygen replenishment. Furthermore, the high concentration of oxygen vacancy would drive electrons to transfer from support to metal, and thus electron-rich and under-coordinated Pt particles that are favorable for toluene adsorption and dissociation are obtained. Attributing to above positive factors, the doping of Gd would effectively enhance the catalytic oxidation of toluene over Pt/CeO 2 catalyst. In addition, the Pt/CeGdO 2 sample exhibits an excellent reaction stability and resistance of concentration impact. [ABSTRACT FROM AUTHOR]

Abstract: Herein, a facile strategy for the in situ growth of a Co3O4‐based precursor with unique hierarchical architectures oriented diagonal or perpendicular to Ni surfaces is reported. This strategy to prepare grafted ZIF‐67@Co3O4 and MOF‐199@Co3O4 precursor structures is based on a simple hydrothermal synthesis method to obtain the Co3O4 precursor and the subsequent in situ growth of ZIF‐67 and MOF‐199, respectively. The morphologies of the Co3O4 products can be tailored by controlling the solvent polarity and concentration of precipitants. CO is chosen as a probe molecule to evaluate the catalytic performance of the as‐synthesized Co3O4‐based oxide catalysts, and the structure–activity relationships are confirmed by using TEM, H2 temperature‐programmed reduction, X‐ray photoelectron spectroscopy, Raman spectroscopy and in situ Raman spectroscopy, and extended X‐ray absorption fine structure analysis. These analysis results demonstrate that irislike Co3O4 exhibits a high catalytic activity for CO oxidation and contains an abundance of surface defect sites (Co3+ species) to result in an excellent low‐temperature reducibility, oxygen vacancies and unsaturated chemical bonds on the surface. Moreover, we used in situ Raman spectroscopy to record the structural transformation of Co3O4 directly during the reaction, which confirmed that CO oxidation on the surface of Co3O4 can proceed through the Langmuir–Hinshelwood mechanism (<200 °C) and the Mars–van Krevelen mechanism (>200 °C). [ABSTRACT FROM AUTHOR]

Ag/CeO 2 catalysts with various shapes of CeO 2 (nanorods, nanoparticles, and nanocubes) were prepared by the hydrothermal and impregnation method and then used for the catalytic oxidation of HCHO at low temperature. TEM and XRD results showed that Ag nanoparticles were well dispersed on the surface of CeO 2 . According to the results from XPS, H 2 -TPR and Raman spectra, Ag/r-CeO 2 , Ag/p-CeO 2 and Ag/c-CeO 2 exhibited different oxygen vacancy concentration, more oxygen vacancy and surface chemisorbed oxygen formed in Ag/r-CeO 2 . There might existed synergetic interaction between Ag and CeO 2 , and the presence of Ag nanoparticles could promoted the activation of surface chemisorbed oxygen, which is favorable for HCHO oxidation. The catalytic properties of the catalysts were significantly dependent on the shapes of CeO 2 , due to the highest surface oxygen vacancy concentration and best reducibility, Ag/r-CeO 2 exhibited the best catalytic activity for HCHO oxidation. Ag/r-CeO 2 showed higher specific reaction rate (7.43 nmol/(s·m 2 ) at 100 °C) and TOF Ag (0.0071 s −1 at 100 °C) under 810 ppm of HCHO and 84,000 h −1 of GHSV. Ag/r-CeO 2 could reach complete HCHO oxidation at around 110 °C, which was lower than that of Ag/p-CeO 2 and Ag/c-CeO 2 . Higher low-temperature reducibility, more surface oxygen vacancies, surface lattice oxygen species, and lattice defects produced by the interaction of Ag and CeO 2 contributed to the excellent catalytic performance of Ag/r-CeO 2 for HCHO oxidation. These results revealed that the HCHO catalytic oxidation activity was dependent on the shapes of CeO 2 supports, this study suggested that the catalytic activity of the metal/CeO 2 catalysts can be regulated by engineering the shapes of CeO 2 supports. [ABSTRACT FROM AUTHOR]

• The MnO x @Eu-CeO x catalysts were prepared by a simple chemical precipitation method. • The MnO x @Eu-CeO x catalysts presented high sulfur-poisoning resistance. • The catalyst with multiple protective effects is the key to high resistance to SO 2. A novel MnO x @Eu-CeO x catalyst with multiple protective attributes was designed and fabricated using a chemical precipitation method and tested for its low temperature SCR activity. The subject MnO x @Eu-CeO x nanorod catalyst exhibited superior SCR performance and strong SO 2 -tolerance. The formation of the composite-shell structure enhanced the catalysts' surface acidity and redox performance, which resulted in excellent SCR performance. Moreover, the TG results suggested that the protective effect of the EuO x -CeO x composite-shell effectively reduced the deposition of the surface sulphates. The XPS, XRD analysis results of the subject catalyst together with theoretical calculations provided strong evidence that there was a strong interaction between Mn and Ce in the MnO x @Eu-CeO x. This significant interaction could provide maximum protection to the core from the effect of SO 2 , which also contributed to the high SO 2 resistance of the catalyst. In situ FT-IR results also indicated that the chemisorbed species on MnO x @Eu-CeO x were much more stable in the presence of SO 2 compared to Eu-CeO x /MnO x , which resulted in the deposition of significantly less sulphates. This low temperature SCR catalyst with multiple protective attributes, including composite shell, strong interaction and core-shell structure, is the key to long-term resistance to SO 2. [ABSTRACT FROM AUTHOR]