OMS-2 nanorods with tunable K(+) concentration were prepared by a facile hydrothermal redox reaction of MnSO4, (NH4)2S2O8, and (NH4)2SO4 at 120 °C by adding KNO3 at different KNO3/MnSO4 molar ratios. The OMS-2 nanorod catalysts are characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption and desorption, inductively coupled plasma, and X-ray photoelectron spectrometry. The effect of K(+) concentration on the lattice oxygen activity of OMS-2 is theoretically and experimentally studied by density functional theory calculations and CO temperature-programmed reduction. The results show that increasing the K(+) concentration leads to a considerable enhancement of the lattice oxygen activity in OMS-2 nanorods. An enormous decrease (ΔT50 = 89 °C; ΔT90 > 160 °C) in reaction temperatures T50 and T90 (corresponding to 50 and 90% benzene conversion, respectively) for benzene oxidation has been achieved by increasing the K(+) concentration in the K(+)-doped OMS-2 nanorods due to the considerable enhancement of the lattice oxygen activity.

Catalytic CO2 reforming of CH4 (CRM) to produce syngas (H2 and CO) provides a promising approach to reducing global CO2 emissions and the extensive utilization of natural gas resources. However, the rapid deactivation of the reported catalysts due to severe carbon deposition at high reaction temperatures and the large energy consumption of the process hinder its industrial application. Here, a method for almost completely preventing carbon deposition is reported by modifying the surface of Ni nanocrystals with silica clusters. The obtained catalyst exhibits excellent durability for CRM with almost no carbon deposition and deactivation after reaction for 700 h. Very importantly, it is found that CRM on the catalyst can be driven by focused solar light, thus providing a promising new approach to the conversion of renewable solar energy to fuel due to the highly endothermic characteristics of CRM. The reaction yields high production rates of H2 and CO (17.1 and 19.9 mmol min−1 g−1, respectively) with a very high solar‐to‐fuel efficiency (η, 12.5%). Even under focused IR irradiation with a wavelength above 830 nm, the η of the catalyst remains as high as 3.1%. The highly efficient catalytic activity arises from the efficient solar‐light‐driven thermocatalytic CRM enhanced by a novel photoactivation effect.

TiO 2 /CeO 2 nanocomposites of anatase TiO 2 nanoparticles supported on microsized mesoporous CeO 2 were prepared and characterized by SEM, TEM, BET, XRD, Raman, XPS, and diffuse reflectance UV−vis absorption. The formation of the TiO 2 /CeO 2 nanocomposites considerably enhances their catalytic activity for the gas-phase oxidation of benzene, one of the hazardous volatile organic compounds (VOCs), under the irradiation of a Xe lamp compared to pure CeO 2 and TiO 2 . A solar-light-driven thermocatalysis on CeO 2 is found for the TiO 2 /CeO 2 nanocomposites. There is a synergetic effect between the photocatalysis on TiO 2 and the thermocatalysis on CeO 2 for the TiO 2 /CeO 2 nanocomposites, which significantly increases their catalytic activity. The CO 2 formation rate (r CO2 ) of the TiO 2 /CeO 2 nanocomposite with the Ti/Ce molar ratio of 0.108 under the synergetic photothermocatalytic condition is 36.4 times higher than its r CO 2 under the conventional photocatalytic condition at near room temperature. CO temperature-programmed reduction (CO-TPR) with the irradiation of the Xe lamp and in the dark reveals that the synergetic effect, which occurs at the interface of the TiO 2 /CeO 2 nanocomposite, is due to the considerable promotion of the CeO 2 reduction by the photocatalysis on TiO 2 .

The octahedral layered birnessite-type manganese oxide (OL-1) with the morphologies of nanoflowers, nanowires, and nanosheets were prepared and characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric/differential scanning calorimetry (TG/DSC), Brunnauer-Emmett-Teller (BET), inductively coupled plasma (ICP), and X-ray photoelectron spectroscopy (XPS). The OL-1 nanoflowers possess the highest concentration of oxygen vacancies or Mn(3+), followed by the OL-1 nanowires and nanosheets. The result of catalytic tests shows that the OL-1 nanoflowers exhibit a tremendous enhancement in the catalytic activity for benzene oxidation as compared to the OL-1 nanowires and nanosheets. Compared to the OL-1 nanosheets, the OL-1 nanoflowers demonstrate an enormous decrease (ΔT(50) = 274 °C; ΔT(90) > 248 °C) in reaction temperatures T50 and T90 (corresponding to 50 and 90% benzene conversion, respectively) for benzene oxidation. The origin of the tremendous effect of morphology on the catalytic activity for the nanostructured OL-1 catalysts is experimentally and theoretically studied via CO temperature-programmed reduction (CO-TPR) and density functional theory (DFT) calculation. The tremendous catalytic enhancement of the OL-1 nanoflowers compared to the OL-1 nanowires and nanosheets is attributed to their highest surface area as well as their highest lattice oxygen reactivity due to their higher concentration of oxygen vacancies or Mn(3+), thus tremendously improving the catalytic activity for the benzene oxidation.

The Pt/CeO 2 nanocomposites of Pt nanoparticles partially confined in the mesopores of microsized mesoporous CeO 2 (1.0% Pt/CeO 2 -MM) or supported on the surface of CeO 2 nanocubes (1.0% Pt/CeO 2 -NC) with the same Pt loading of 1.0 wt % were prepared by the impregnation of microsized mesoporous CeO 2 or CeO 2 nanocubes with Pt(NO 3 ) 2 aqueous solution, followed by the reduction with NaBH 4 aqueous solution. 1.0%Pt/CeO 2 -MM exhibits much higher catalytic activity for benzene oxidation than 1.0%Pt/CeO 2 -NC. Compared to 1.0% Pt/CeO 2 -NC, the reaction temperatures of T 50 and T 90 (corresponding to a benzene conversion = 50% and 90%) for 1.0% Pt/CeO 2 -MM tremendously decreases by ΔT 50 = 149 °C and ΔT 90 = 196 °C, respectively. The turnover frequency (TOF) of 1.0% Pt/CeO 2 -MM at 140 °C increases by 9.0 times as compared to that of 1.0% Pt/CeO 2 -NC. The tremendous enhancement in the catalytic activity is due to a novel metal support interaction in 1.0% Pt/CeO 2 -MM. The novel metal support interaction is theoretically studied by density function theory (DFT) calculation and experimentally studied by CO-TPR, CO-TPD, H 2 pulse titration, and HRTEM. The theoretical and experimental evidence reveal that the partial confinement of Pt nanoparticles in the mesopores of microsized mesoporous CeO 2 leads to a significant enhancement in the activity of the surface lattice oxygen around the interface between Pt nanoparticles and CeO 2 , thus tremendously increasing the catalytic activity.