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[Display omitted] • Small and uniform CeO 2 nanoparticles were prepared on Al 2 O 3 (CA-T) using a two-step incipient wetness impregnation method. • Pt single sites anchored to step sites of small CeO 2 entities within CA-T were more stable than those anchored to crystal surface of large CeO 2 particles on regular ceria-alumina. • The reactivity of CO adsorbed on Pt sites decreased by Pt cluster step sites ≈ Pt cluster terrace sites > Pt cluster corner sites ≫ Pt single sites on CeO 2. • Abundant Pt cluster step and terrace sites as well as rich Pt-CeO 2 interfaces facilitated the activated Pt/CA-T catalyst for efficient CO oxidation at low temperatures. In heterogeneous catalysis, the promotion of low temperature activity and enhancement of thermal stability simultaneously especially for precious metal catalysts is always highly demanded but very challenging. Herein we report a novel Pt catalyst on ceria-alumina (CeO 2 /Al 2 O 3) support (Pt/CA-T) engineered by a two-step ceria deposition strategy, exhibiting superior thermal stability and low-temperature carbon monoxide (CO) oxidation activity after activation. Pt single sites anchored to engineered CeO 2 edge sites are much more stable than that to CeO 2 (111) surface, and such stable single sites can be transformed into highly active Pt clusters for efficient low-temperature CO oxidation. Active site identification indicates that the CO oxidation activity of different Pt sites follows such sequence: Pt cluster step sites ≈ Pt cluster terrace sites > Pt cluster corner sites ≫ Pt single sites on CeO 2. The excellent low temperature activity of activated Pt/CA-T catalyst for CO oxidation is associated with its abundant Pt cluster step and terrace sites as well as rich Pt-CeO 2 interfaces, which facilitate the adsorption of active CO species and superior oxygen activation/transfer ability. The present study provides new insights into the structure–activity relationship of Pt-CeO 2 -Al 2 O 3 catalyst, which can also guide the preparation of other highly robust supported catalysts for important industrial applications. [ABSTRACT FROM AUTHOR]

Catalytic combustion of methane is widely used in industrial and transportation activities. The commonly used Pd‐based catalysts, however, are easily deactivated under hydrothermal conditions. In this work, we adopted a novel strategy to prepare a GaOx‐doped Pd/Al2O3 catalyst via the oxidative transformation of intermetallic Pd5Ga3 nanocrystals supported on γ‐Al2O3. We observed a synergistic effect between palladium and gallium oxide via formation of a bi‐functional active Pd−O−Ga phase, resulting in a highly active and exceptionally stable catalyst that could markedly suppress the sintering of noble metals under harsh conditions (hydrothermal treatment at 750 °C). Moreover, the presence of a large amount of surface oxygen vacancies and the surface Pd−O−Ga phase could promote methane combustion over the catalysts. It is believed that such a novel dual‐metal catalyst is promising in practical applications for methane combustion. Effective synergy: The Pd−GaOx/Al2O3 catalysts are prepared via the oxidative transformation of intermetallic Pd5Ga3 nanocrystals supported on Al2O3. A synergistic effect between palladium and gallium oxide via formation of a bi‐functional active Pd−O−Ga phase is observed, resulting in a highly active and exceptionally stable catalyst that can markedly suppress the sintering of noble metals under harsh conditions. Surface oxygen vacancies and the surface Pd−O−Ga phase are the catalytically active sites. [ABSTRACT FROM AUTHOR]

The pervasive use of toxic nitroaromatics in industrial processes and their prevalence in industrial effluent has motivated the development of remediation strategies, among which is their catalytic reduction to the less toxic and synthetically useful aniline derivatives. While this area of research has a rich history with innumerable examples of active catalysts, the majority of systems rely on expensive precious metals and are submicron- or even a few-nanometer-sized colloidal particles. Such systems provide invaluable academic insight but are unsuitable for practical application. Herein, we report the fabrication of catalysts based on ultralow loading of the semiprecious metal ruthenium on 2–4 mm diameter spherical alumina monoliths. Ruthenium loading is achieved by atomic layer deposition (ALD) and catalytic activity is benchmarked using the ubiquitous para-nitrophenol, NaBH4 aqueous reduction protocol. Recyclability testing points to a very robust catalyst system with intrinsic ease of handling. [ABSTRACT FROM AUTHOR]

Herein we fabricated the supported single-atom silver catalysts using an in situ molten salt method. The Mn 2 O 3 nanowires supported single-atom silver catalyst (i.e., 0.06 wt% Ag/Mn 2 O 3) exhibited excellent catalytic activity for toluene combustion, with the temperatures required for 50 and 90% of toluene conversions being 170 and 205 °C, respectively, at a space velocity of 40,000 mL/(g h). However, the toluene conversion at 205 °C quickly decreased from 90 to 30% within 2.5 h of on-stream reaction. Based on the various characterization results, we found that there were no aggregation of Ag particles, no change in crystal structure of the Mn 2 O 3 nanowire support, and no carbon deposition on the catalyst surface, and the quick deactivation of 0.06 wt% Ag/Mn 2 O 3 was mainly associated with the low oxygen activation ability. The proper CeO 2 addition to the 0.06 wt% Ag/Mn 2 O 3 catalyst was found to not only improve the catalytic activity but also significantly enhance the stability of the catalyst. Toluene conversion at 195 °C over 0.63 wt% CeO 2 -0.06 wt% Ag/Mn 2 O 3 decreased by only 10% in 50 h of on-stream reaction. Because Ag and CeO 2 particles were highly dispersed on the Mn 2 O 3 nanowire support, the oxygen species formed at the surface oxygen vacancies of CeO 2 could efficiently migrate to the active sites (i.e., the interface of Ag-Mn 2 O 3) and replenish the surface reactive lattice oxygen species. Thus, the present single-atom silver catalyst is an alternative for commercial noble metal catalysts for the removal of VOCs. An in situ molten salt strategy is developed for the convenient preparation of Mn 2 O 3 nanowires-supported single-atom silver catalysts with high activity for toluene oxidation. The significant enhancement in catalytic stability of the ceria-modified single-atom silver catalyst is due to the timely replenishment of the surface reactive lattice oxygen species. Unlabelled Image • Single-atom Ag catalyst is prepared using an in situ molten salt method. • Single-atom Ag catalyst exhibits high catalytic activity for toluene removal. • Ce-doping greatly enhances catalytic stability of single-atom Ag catalyst. • Timely replenishment of surface reactive lattice oxygen species is important. • Single-atom Ag catalyst is an alternative for commercial noble metal catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new CuO-CeO 2 based catalyst for efficient NO reduction by CO was designed. • Highly dispersed CuO x clusters were created on surface modified CeO 2 -Al 2 O 3 support. • Catalytic domains of Cu+-□-Ce3+ at the CuO x clusters-CeO 2 interfaces were fabricated. • The intrinsic structure–activity relationship was established for NO + CO reaction. CuO-CeO 2 based materials have been recognized as promising substitutes for precious metal catalysts in emission control field due to their superior redox property and low cost. Herein, by optimizing the deposition process of CeO 2 and CuO onto γ-Al 2 O 3 , highly dispersed CuO clusters on unique CeO 2 -Al 2 O 3 support with small CeO 2 particles (7Cu-Ce/CeAl) were successfully constructed for efficient NO reduction by CO, which exhibited much higher NO removal efficiency and N 2 selectivity than CuO catalysts supported on γ-Al 2 O 3 (7Cu/Al) and conventional CeO 2 -Al 2 O 3 support (7Cu/CeAl). Moreover, H 2 O showed limited inhibition effect on the catalytic performance of 7Cu-Ce/CeAl catalyst. With the help of Raman spectra, X-ray absorption spectroscopy, in situ diffuse reflectance infrared Fourier transform spectroscopy, etc. , it was clearly revealed that the abundant Cu+/Ce3+ paired sites with surface synergetic oxygen vacancies (SSOV) on 7Cu-Ce/CeAl catalyst could effectively facilitate the adsorption and activation of CO and NO, thus significantly enhancing the NO removal efficiency. [ABSTRACT FROM AUTHOR]

An in situ molten salt strategy is developed for the convenient preparation of iron oxide-supported platinum catalysts with high performance for o -xylene elimination. The high catalytic performance of the supported platinum catalysts is due to the improvement in redox ability and o -xylene activation. • Supported Pt catalyst is prepared using an in situ molten salt method. • Supported Pt catalyst exhibits high catalytic activity for o -xylene removal. • Pt loading enhances the redox ability of the supported Pt catalyst. • Pt loading improves the adsorption and activation of o -xylene. • Improvement in redox ability and o -xylene activation benefit high activity. Supported noble metal catalysts are highly effective for eliminating volatile organic compounds (VOCs). A catalyst with less noble metal loading is always desirable. Using a mixture of NaNO 3 and NaF as molten salt, Fe(NO 3) 3 and Pt(NH 3) 4 (NO 3) 2 as metal precursors, x Pt/Fe 2 O 3 catalysts (x = 0–0.3 wt%) were fabricated after calcination at 350 °C for 3 h. At space velocity of 40,000 mL/(g h), 0.22 wt% Pt/Fe 2 O 3 showed the best catalytic activity, and o -xylene could be completely oxidized into CO 2 and H 2 O at 225 °C. Furthermore, 0.22 wt% Pt/Fe 2 O 3 exhibited good stability, and high resistance to water vapor, CO 2 , and SO 2. We deduce that the excellent catalytic performance of 0.22 wt% Pt/Fe 2 O 3 was associated with the high dispersion of the Pt species and good low-temperature reducibility. The possible reaction mechanism of o -xylene oxidation over 0.22 wt% Pt/Fe 2 O 3 involved the adsorption of o -xylene molecules, partial decomposition into small organic intermediates (e.g. maleic anhydride and aliphatic carboxylate species), and total oxidation into CO 2 and H 2 O. Due to the high efficiency, good stability, low cost, and convenient preparation, the present catalysts are promising for the practical removal of VOCs. [ABSTRACT FROM AUTHOR]

Three-dimensionally ordered macro-/mesoporous 26.9 wt% CeO 2 –Al 2 O 3 (denoted as 3DOM 26.9CeO 2 –Al 2 O 3 )-supported noble metal nanocatalysts ( x M/3DOM 26.9CeO 2 –Al 2 O 3 , x = 0.27–0.81 wt%; M = Au, Ag, Pd, and Pt) were prepared using the polymethyl methacrylate-templating and polyvinyl pyrrolidone- or polyvinyl alcohol-protected reduction methods, respectively. It is shown that the x M/3DOM 26.9CeO 2 –Al 2 O 3 samples displayed a high-quality 3DOM architecture with a bimodal pore (macropore size = 180–200 nm and mesopore size = 4–6 nm) structure and a surface area of 102–108 m 2 /g, with the noble metal nanoparticles (3–4 nm in size) being highly dispersed on the 3DOM 26.9CeO 2 –Al 2 O 3 surface. The 0.27Pt/3DOM 26.9CeO 2 –Al 2 O 3 sample performed the best ( T 90% = 198 °C at space velocity = 20,000 mL/(g h)) for toluene oxidation. The addition of moisture to the feedstock induced a positive effect on catalytic activity. The apparent activation energies obtained over the x M/3DOM 26.9CeO 2 –Al 2 O 3 samples were in the range of 46–100 kJ/mol, with the 0.27Pt/3DOM 26.9CeO 2 –Al 2 O 3 sample possessing the lowest apparent activation energy. It is concluded that the good catalytic performance of 0.27Pt/3DOM 26.9CeO 2 –Al 2 O 3 was associated with its higher adsorbed oxygen species concentration, better low-temperature reducibility, and stronger interaction between Pt and 3DOM 26.9CeO 2 –Al 2 O 3 as well as the unique bimodal porous structure. [ABSTRACT FROM AUTHOR]

Three-dimensionally ordered macroporous (3DOM) photocatalysts BiVO 4 (denoted as 3D-BiV), AgBr/3D-BiV, and 0.17 wt% M/AgBr/3D-BiV (M Au, Pt, and Pd) were prepared using the polymethyl methacrylate-templating, low-temperature deposition, and polyvinyl alcohol-protected reduction methods, respectively. The as-prepared BiVO 4 possessed a good-quality 3DOM structure and a high surface area. It is found that the AgBr and noble metals were uniformly distributed on the surface of 3D-BiV. Among the M/AgBr/3D-BiV samples, the 0.17 wt% Pd/AgBr/3D-BiV sample showed the highest photocatalytic activity for the degradation of 4-chlorophenol (4-CP) under visible light illumination (i.e., complete 4-CP degradation could be achieved within 150 min), which was associated with its good 3DOM structure, high surface oxygen adspecies concentration, easy transfer and separation of photogenerated carriers, and synergistic effect between AgBr or Pd nanoclusters and BiVO 4 . [ABSTRACT FROM AUTHOR]