Abstract:Three-dimensional nanomaterials are generally beneficial to the catalytic performance because of larger specific surface aera, more exposed active sites, promoted mass transfer and shorter diffusion distance between reactants and catalysts....
“…The stacking mode between the sheets is changed; thus, the three-dimensional space of 5-CBMOS is significantly stronger than that of BMOS. It assists in exposing more catalytic active sites, which is beneficial for the adsorption and activation of O 2 and reactants. , Figure e is the TEM image of 5-CBMOS, showing the ultrathin sheet structure, which is consistent with the SEM results. The crystal structure of 5-CBMOS is further magnified, and the lattice fringes with a spacing of 0.274 nm correspond to the {002} crystal plane of the orthorhombic phase Bi 2 MoO 6 (Figure f). , Energy-dispersive X-ray spectroscopy (TEM–EDX) results of the prepared samples indicate that Bi, Ce, Mo, and O elements contained in 5-CBMOS are uniformly distributed in the matrix material (Figure g), which further confirm the successful synthesis of the Ce-doped Bi 2 MoO 6 composite.…”
Section: Resultssupporting
confidence: 80%
“…By comparing the SEM images of BMOS and 5-CBMOS, Ce doping has few effects on the thickness, but it can make the sheet size of Bi 2 MoO 6 increase slightly.The stacking mode between the sheets is changed; thus, the threedimensional space of 5-CBMOS is significantly stronger than that of BMOS. It assists in exposing more catalytic active sites, which is beneficial for the adsorption and activation of O 2 and reactants 42,43. Figure1eis the TEM image of 5-CBMOS, showing the ultrathin sheet structure, which is consistent with the SEM results.…”
The generation of reactive oxygen species (ROS) from O 2 is a critical step to boost the performance of photocatalytic toluene oxidation. However, the production of ROS is greatly limited by the serious recombination of charge carriers and the lack of O 2 adsorption sites. In this work, Ce-doped Bi 2 MoO 6 ultrathin nanosheets with rich oxygen defects are prepared by a one-step hydrothermal method. The ultrathin structure promotes the longitudinal transport of carriers to the surface. The introduction of Ce ions generates both Ce 3+ /Ce 4+ redox ion pairs and oxygen defects in Bi 2 MoO 6 , where the former promotes the transfer of photogenerated electrons and the latter enhances the adsorption of O 2 , thereby producing more superoxide radicals (•O 2 − ). Attributed to these advantages, Ce-doped Bi 2 MoO 6 ultrathin nanosheets exhibit excellent photocatalytic activity for toluene selective oxidation. The toluene conversion rate is 4422 μmol•g −1 •h −1 . The selectivity values of benzaldehyde and benzyl alcohol are 84.7 and 15.3%, respectively. In addition, the mechanism of photocatalytic selective oxidation of toluene is further explored through a series of experiments.
“…The stacking mode between the sheets is changed; thus, the three-dimensional space of 5-CBMOS is significantly stronger than that of BMOS. It assists in exposing more catalytic active sites, which is beneficial for the adsorption and activation of O 2 and reactants. , Figure e is the TEM image of 5-CBMOS, showing the ultrathin sheet structure, which is consistent with the SEM results. The crystal structure of 5-CBMOS is further magnified, and the lattice fringes with a spacing of 0.274 nm correspond to the {002} crystal plane of the orthorhombic phase Bi 2 MoO 6 (Figure f). , Energy-dispersive X-ray spectroscopy (TEM–EDX) results of the prepared samples indicate that Bi, Ce, Mo, and O elements contained in 5-CBMOS are uniformly distributed in the matrix material (Figure g), which further confirm the successful synthesis of the Ce-doped Bi 2 MoO 6 composite.…”
Section: Resultssupporting
confidence: 80%
“…By comparing the SEM images of BMOS and 5-CBMOS, Ce doping has few effects on the thickness, but it can make the sheet size of Bi 2 MoO 6 increase slightly.The stacking mode between the sheets is changed; thus, the threedimensional space of 5-CBMOS is significantly stronger than that of BMOS. It assists in exposing more catalytic active sites, which is beneficial for the adsorption and activation of O 2 and reactants 42,43. Figure1eis the TEM image of 5-CBMOS, showing the ultrathin sheet structure, which is consistent with the SEM results.…”
The generation of reactive oxygen species (ROS) from O 2 is a critical step to boost the performance of photocatalytic toluene oxidation. However, the production of ROS is greatly limited by the serious recombination of charge carriers and the lack of O 2 adsorption sites. In this work, Ce-doped Bi 2 MoO 6 ultrathin nanosheets with rich oxygen defects are prepared by a one-step hydrothermal method. The ultrathin structure promotes the longitudinal transport of carriers to the surface. The introduction of Ce ions generates both Ce 3+ /Ce 4+ redox ion pairs and oxygen defects in Bi 2 MoO 6 , where the former promotes the transfer of photogenerated electrons and the latter enhances the adsorption of O 2 , thereby producing more superoxide radicals (•O 2 − ). Attributed to these advantages, Ce-doped Bi 2 MoO 6 ultrathin nanosheets exhibit excellent photocatalytic activity for toluene selective oxidation. The toluene conversion rate is 4422 μmol•g −1 •h −1 . The selectivity values of benzaldehyde and benzyl alcohol are 84.7 and 15.3%, respectively. In addition, the mechanism of photocatalytic selective oxidation of toluene is further explored through a series of experiments.
“…As shown in Figure 2B, the strong characteristic peaks centered at around 1602 and 1342 cm −1 are attributed to the graphitic carbon (G-band) and disordered carbon (D-band), respectively. 66 The values of I G /I D were 0.89, 0.92, and 1.0 for Pd/CNS-700, Pd/CNS-800, and Pd/CNS-900, respectively, indicating that the graphitic carbon was more readily obtained at higher calcination temperature. In Figure 2C, the diffraction peak at 2ϴ = 24°corresponds to the d-spacing of graphitic carbon (002) (JCPDS Card No.…”
Section: Resultsmentioning
confidence: 92%
“…These absorption peaks, except for the –OH group, were comparatively weaker in Pd/CNS‐700, Pd/CNS‐800, and Pd/CNS‐900, indicating that the surface functional groups were carbonized at high temperature. As shown in Figure 2B, the strong characteristic peaks centered at around 1602 and 1342 cm −1 are attributed to the graphitic carbon (G‐band) and disordered carbon (D‐band), respectively 66 . The values of I G / I D were 0.89, 0.92, and 1.0 for Pd/CNS‐700, Pd/CNS‐800, and Pd/CNS‐900, respectively, indicating that the graphitic carbon was more readily obtained at higher calcination temperature.…”
In spite of the numerous advances in the development of H 2 and O 2 evolutions upon water splitting, the separation of H 2 from O 2 still remains a severe challenge. Herein, the novel dual-functional nanocatalysts Pd/ carbon nanosphere (CNS), obtained via immobilization of ultrafine Pd nanoparticles onto CNS, are developed and employed for both selective H 2 generation from HCOOH dehydrogenation and O 2 evolution from H 2 O 2 decomposition. In these reactions, the highest activities for Pd/CNS-800 (i.e., calcinated at 800°C) are 2478 h −1 and 993 min −1 for H 2 and O 2 evolution, respectively. The highly efficient and selective "on-off" switch for selective H 2 generation from HCOOH is successfully realized by pH adjustment. This novel and highly efficient nanocatalyst Pd/CNS-800 not only provides new approaches for the promising application of HCOOH and H 2 O 2 as economic and safe H 2 and O 2 carriers, respectively, for fuel cells, but also promotes the development of "on-off" switch for ondemand H 2 evolution.carbon nanospheres, H 2 generation, O 2 evolution, "on-off" switch, Pd nanoparticles
| INTRODUCTIONSince the H 2 -O 2 fuel cell was first discovered by Grove in 1839, 1 it has been widely deemed as the most potential portable and auxiliary power generator because of its merits of green, simple structure, wide operating temperature range, high specific energy, and high energy conversion efficiency. Although H 2 and O 2 are easily produced by water electrolysis, 2-5 it is difficult to find ideal catalysts for this reaction and to separate H 2 from Carbon Energy.
“…In order to further detect the species and vacancies of oxygen on the surface of the synthesized catalyst, the O1S was investigated (Figure 2c,d). The O1S of the XPS spectrum was decomposed into two parts, including saturated lattice oxygen (situated around 529.70 eV) and surface-absorbed oxygen species (situated around 531.30 eV) [54]. The CeAY surface-absorbed oxygen species concentration was dominantly higher than that of CeO 2 , and after the CeO 2 was added to the acid-treated clay, the saturated lattice oxygen completely disappeared.…”
The treatment of acid wastewater to remove organic matter in acid wastewater and recycle valuable resources has great significance. However, the classical advanced oxidation process (AOPs), such as the Fenton reaction, encountered a bottleneck under the conditions of strong acid. Herein, making use of the oxidation properties of CeAY (CeO2@acid clay), we built an AOPs reaction system without H2O2 under a strong acid condition that can realize the transformation of organic matter in industrial wastewater. The X-ray photoelectron spectroscopy (XPS) proved that the CeAY based on Ce3+ as an active center has abundant oxygen vacancies, which can catalyze O2 to produce reactive oxygen species (ROS). Based on the electron spin-resonance spectroscopy spectrum and radical trapping experiments, the production of •O2– and •OH can be determined, which are the essential factors of the degradation of organic compounds. In the system of pH = 1.0, when 1 mg CeAY is added to 10 mL of wastewater, the degradation efficiency of an aniline solution with a 5 mg/L effluent concentration is 100%, and that of a benzoic acid solution with a 100 mg/L effluent concentration is 50% after 10 min of reaction. This work may provide novel insights into the removal of organic pollutants in a strong acid water matrix.
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