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Three-dimensionally ordered macroporous La 0.6 Sr 0.4 CoO 3 (3DOM LSCO) and its supported gold and manganese oxide ( y Mn 3 O 4 - z Au/3DOM LSCO; y = 0.75–2.50 wt%, z = ca. 2.0 wt%) nanoparticles (NPs) were prepared using the polymethyl methacrylate-templating, polyvinyl alcohol-protected reduction, and physical adsorption methods, respectively. Physicochemical properties of the samples were characterized by means of numerous techniques, and their catalytic activities were evaluated for the oxidation of toluene. It is shown that the 3DOM LSCO in y Mn 3 O 4 - z Au/3DOM LSCO with a surface area of 20–24 m 2 /g displayed a rhombohedral crystal structure, and Mn 3 O 4 (size: 5–12 nm) and Au (size: 3–4 nm) NPs were highly dispersed on the surface of 3DOM LSCO. There were good correlations of adsorbed oxygen species concentration and low-temperature reducibility with catalytic activity of the sample. The 1.67Mn 3 O 4 -2Au/3DOM LSCO sample performed the best, giving the T 50% and T 90% (temperatures required for achieving toluene conversions of 50 and 90%) of 214 and 230 °C at a space velocity of 20,000 mL/(g h), respectively. The introduction of water vapor to the reaction system caused a partial deactivation of the 1.67Mn 3 O 4 -2Au/3DOM LSCO sample, and such a deactivation was reversible. The apparent activation energies (41.7–47.4 kJ/mol) obtained over y Mn 3 O 4 -2Au/3DOM LSCO were lower than those (49.2–56.8 kJ/mol) obtained over 3DOM LSCO, 2Au/3DOM LSCO, and 1.56Mn 3 O 4 -2Au/Bulk LSCO. It is concluded that the large surface area, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between Au or Mn 3 O 4 NPs and 3DOM LSCO were responsible for the good catalytic performance of 1.67Mn 3 O 4 -2Au/3DOM LSCO. [ABSTRACT FROM AUTHOR]

Three-dimensionally ordered macroporous (3DOM) LaMnAl 11 O 19 and x AuPd y /3DOM LaMnAl 11 O 19 ( x = 0.44 − 1.91 wt%; y = 1.80 − 1.86) were prepared via the polymethyl methacrylate (PMMA)-templating and gas bubble-assisted polyvinyl alcohol (PVA)-protected reduction routes, respectively. Physicochemical properties of the samples were characterized by a number of analytical techniques. Catalytic activities of the samples were measured for methane combustion in a continuous-flow microreactor. It is shown that the LaMnAl 11 O 19 in each of the samples was hexagonal in crystal structure, and all of the samples possessed a good-quality 3DOM architecture with a surface area of 24.4 − 28.2 m 2 /g. The Au–Pd nanoparticles (NPs) with an average size of 2.8 nm were uniformly dispersed on the macropore walls of 3DOM LaMnAl 11 O 19 . The 1.91AuPd 1.80 /3DOM LaMnAl 11 O 19 sample performed the best for methane combustion ( T 50% = 342 °C and T 90% = 402 °C at a space velocity of 20,000 mL/(g h)). The deactivation of the 1.91AuPd 1.80 /3DOM LaMnAl 11 O 19 catalyst induced by water vapor introduction was reversible, whereas that induced by SO 2 addition was irreversible. It is concluded that the good catalytic activity of 1.91AuPd 1.80 /3DOM LaMnAl 11 O 19 was related to its good-quality 3DOM structure, highly dispersed Au–Pd NPs, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between Au–Pd alloy NPs and 3DOM LaMnAl 11 O 19 . [ABSTRACT FROM AUTHOR]

Three-dimensionally ordered macroporous (3DOM) CoFe 2 O 4 , z MnO x /3DOM CoFe 2 O 4 ( z = 4.99–12.30 wt%), and y Pd–Pt/6.70 wt% MnO x /3DOM CoFe 2 O 4 ( y = 0.44–1.81 wt%; Pd/Pt molar ratio = 2.1–2.2) have been prepared using the polymethyl methacrylate microspheres-templating, incipient wetness impregnation, and bubble-assisted polyvinyl alcohol-protected reduction strategies, respectively. All of the samples were characterized by means of various techniques. Catalytic performance of the samples was measured for methane combustion. It is shown that the as-prepared samples exhibited a high-quality 3DOM structure (103 ± 20 nm in pore size) and a surface area of 19–28 m 2 /g, and the noble metal or alloy nanoparticles (NPs) with a size of 2.2–3.0 nm were uniformly dispersed on the macropore wall surface of 3DOM CoFe 2 O 4 . The loading of MnO x on CoFe 2 O 4 gave rise to a slight increase in activity, however, the dispersion of Pd–Pt NPs on 6.70MnO x /3DOM CoFe 2 O 4 significantly enhanced the catalytic performance, with the 1.81Pd 2.1 Pt/6.70MnO x /3DOM CoFe 2 O 4 sample showing the highest activity ( T 10% = 255 °C, T 50% = 301 °C, and T 90% = 372 °C at a space velocity of 20,000 mL/(g h)). We believe that the excellent catalytic activity of 1.81Pd 2.1 Pt/6.70MnO x /3DOM CoFe 2 O 4 was related to its well-dispersed Pd–Pt alloy NPs, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between MnO x or Pd–Pt NPs and 3DOM CoFe 2 O 4 . [ABSTRACT FROM AUTHOR]

Three-dimensionally ordered macroporous CoCr 2 O 4 (3DOM CoCr 2 O 4 ) and its supported Au–Pd alloy ( x AuPd y /3DOM CoCr 2 O 4 ; x = 0.98 and 1.93 wt%; Pd/Au molar ratio ( y ) = 1.93–1.96) nanocatalysts were prepared using the polymethyl methacrylate-templating and polyvinyl alcohol-protected reduction methods, respectively. Physicochemical properties of the samples were characterized by means of a number of techniques, and their catalytic activities were evaluated for methane combustion. The 3DOM CoCr 2 O 4 and x AuPd y /3DOM CoCr 2 O 4 samples possessed a high-quality 3DOM structure and a surface area of 33–36 m 2 /g. The Au–Pd alloy nanoparticles (NPs) with an average size of 3.3 nm were uniformly dispersed on the surface of the samples. The 1.93AuPd 1.95 /3DOM CoCr 2 O 4 sample showed the best catalytic performance: the T 10% , T 50% , and T 90% (temperatures required for achieving methane conversion of 10, 50, and 90%, respectively) were 305, 353, and 394 °C at a space velocity (SV) of 20,000 mL/(g h). The effects of SV, water vapor, and sulfur dioxide on the catalytic activity of the 1.93AuPd 1.95 /3DOM CoCr 2 O 4 sample were also examined. It is concluded that the excellent catalytic performance of 1.93AuPd 1.95 /3DOM CoCr 2 O 4 was associated with the higher surface area and adsorbed oxygen species concentration, better low-temperature reducibility, and strong interaction between Au–Pd alloy NPs and 3DOM CoCr 2 O 4 . [ABSTRACT FROM AUTHOR]

The three-dimensionally ordered macroporous (3DOM) BiVO 4 and its supported iron oxide ( x Fe 2 O 3 /3DOM BiVO 4 , x = 0.18, 0.97, and 3.40 wt%) photocatalysts were prepared using the ascorbic acid-assisted polymethyl methacrylate-templating and incipient wetness impregnation methods, respectively. Physicochemical properties of the materials were characterized by means of numerous analytical techniques, and their photocatalytic activities were evaluated for the degradation of 4-nitrophenol under visible light illumination. It is found that the BiVO 4 possessed a high-quality 3DOM architecture with a monoclinic crystal phase, and the Fe 2 O 3 was highly dispersed on the surface of 3DOM BiVO 4 . The x Fe 2 O 3 /3DOM BiVO 4 samples much outperformed the 3DOM BiVO 4 sample, and 0.97Fe 2 O 3 /3DOM BiVO 4 showed the best photocatalytic performance (98% 4-nitrophenol was degraded in the presence of 0.6 mL H 2 O 2 within 30 min of visible light illumination) and excellent photocatalytic stability. The introduction of H 2 O 2 to the reaction system could promote the photodegradation of 4-nitrophenol by providing the active OH species generated via the reaction of photoinduced electrons and H 2 O 2 . The pseudo-first-order reaction rate constants (0.0876–0.1295 min −1 ) obtained over x Fe 2 O 3 /3DOM BiVO 4 were much higher than those (0.0033–0.0395 min −1 ) obtained over 3DOM or Bulk BiVO 4 and Fe 2 O 3 /Bulk BiVO 4 , with the 0.97Fe 2 O 3 /3DOM BiVO 4 sample exhibiting the highest rate constant. The enhanced photocatalytic performance of 0.97Fe 2 O 3 /3DOM BiVO 4 was associated with its unique porous architecture, high surface area, Fe 2 O 3 − BiVO 4 heterojunction, good light-harvesting ability, high adsorbed oxygen species concentration, and excellent separation efficiency of photogenerated electrons and holes as well as the photo-Fenton degradation process. [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]