Selective catalytic reduction of NO  by H2 over Pd/TiO2 catalyst

Zhang, Yiyang; Zeng, Hui; Jia, Bin; Wang, Zhihua; Liu, Zhiming

doi:10.1016/s1872-2067(19)63297-3

Cited by 25 publications

(18 citation statements)

References 42 publications

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“…Figure 7a. Based on the binding energy reported in the literature and the symmetric peaks, it can be clearly seen that two states of palladium are presented on the surface of these catalysts [30]. The two characteristic peaks of Pd 3d 3/2 and Pd 3d 5/2 for the Pd 0 metallic state are at 339.8-340.5 eV and 335.3 eV, respectively.…”

Section: Icp and Co Chemisorptionmentioning

confidence: 81%

Y-Modified MCM-22 Supported PdOx Nanocrystal Catalysts for Catalytic Oxidation of Toluene

et al. 2019

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A series of rare earth elements (REEs)-modified and Mobil Composition of Matter (MCM)-22-supported Pd nanocrystal catalysts were synthesized via a high-temperature solution-phase reduction method and tested for toluene complete oxidation. These catalytic materials were systematically characterized by N2 adsorption/desorption, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive spectroscopy (EDS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), temperature-programmed surface reaction of toluene (toluene-TPSR) and X-ray photoelectron spectroscopic (XPS) techniques in order to investigate the structure–catalytic property relationship. Moreover, catalysts with an appropriate yttrium content greatly improved the catalytic activity of 0.2%Pd/MCM-22. PdOx (x = 0, 1) nanoparticles, ranging from 3.6 to 6.8 nm, which were well distributed on the surface of MCM-22. Efficient electron transfer from the Pd2+/Pd0 redox cycle facilitated the catalytic oxidation process, and the formation of Pd (or Y) –O–Si bonds improved the high dispersion of the PdOx and Y2O3 particles. Toluene–TPSR experiments suggested that the addition of Y2O3 improved the physical/chemical adsorption of 0.2%Pd/MCM-22, thus increasing the toluene adsorption capacity. Then, 0.2%Pd/7.5%Y/MCM-22 exhibited the highest catalytic performance. In addition, this catalyst maintained 95% conversion with high resistance to water and chlorine poisoning, even after toluene oxidation at 210 °C for 100 h, making it more valuable in practical applications.

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Section: Icp and Co Chemisorptionmentioning

confidence: 81%

Y-Modified MCM-22 Supported PdOx Nanocrystal Catalysts for Catalytic Oxidation of Toluene

et al. 2019

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“…Compared with NH 3 -SCR, H 2 -SCR has attracted much attention due to the clean reductant H 2 and the high low-temperature activity. − At present, noble metals, such as Pt − and Pd, , have been regarded as the most promising catalysts for the H 2 -SCR reaction. Since Pd exhibited higher N 2 selectivity than Pt in the H 2 -SCR of NO x , Pd-based catalysts have been intensively studied. − However, the narrow temperature window and the relatively low NO x conversion have restricted the application of Pd-based catalysts.…”

Section: Introductionmentioning

confidence: 99%

Unraveling the Promotional Effect of Co on the Pd/TiO₂ Catalyst for H₂-SCR of NO_x in the Presence of Oxygen

Zhang

et al. 2023

J. Phys. Chem. C

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The effect of the introduction of Co to the Pd/TiO 2 catalyst for selective catalytic reduction of NO x by H 2 (H 2 -SCR) in the presence of oxygen has been systematically investigated in the present study. The additive Co can not only obviously improve NO x conversion but also enhance N 2 selectivity. The added Co induced the formation of Pd 0 over the bimetallic PdCo/TiO 2 catalyst, which is greatly conducive to the H 2 -SCR reaction. The spillover of H 2 was promoted due to the introduction of Co over PdCo/TiO 2 . In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) revealed that the addition of Co not only contributed to the adsorption and activation of NO x but also led to the generation of NH 3 species adsorbed on Lewis acid sites, making the reduction of NO x by the H 2 -SCR combined with NH 3 -SCR routes. All of these are responsible for the enhanced catalytic performance of the bimetallic PdCo/TiO 2 catalyst. The investigation would provide guidelines for the rational design of a highly active H 2 -SCR catalyst for the removal of NO x .

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“…Among supported noble metal (Pt, Pd, Ir) catalysts, palladium-based catalysts were usually used as potential catalysts for industrial application due to their high selectivity. − Catalytic activities of Pd-based catalysts were found to be dependent on the chemical nature of Pd species and types of NO x adsorbed species. Metallic Pd (Pd 0 ) is more desirable than palladium oxides. , Pd 0 not only showed superior performance in the adsorption of NO , but also was beneficial in the activation of H 2 .…”

Section: Introductionmentioning

confidence: 99%

Photothermal Synergism on Pd/TiO₂ Catalysts with Varied TiO₂ Crystalline Phases for NO_x Removal via H₂-SCR: A Transient DRIFTS Study

Zhang

Luo

et al. 2022

Ind. Eng. Chem. Res.

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In this work, photothermal synergism over Pd/TiO2 catalysts with varying rutile and anatase phases was investigated for selective catalytic reduction of NO with H2. In the absence of light, two NO x reduction peaks were observed over Pd/TiO2 catalysts. Pd/TiO2-R exhibited better NO x conversion (65 vs 30%) at 75 °C, while Pd/TiO2-A delivered higher activity (82 vs 40%) at 225 °C. Light excitation exerted a more significant promotional effect over Pd/TiO2-R than over the Pd/TiO2-A catalyst. Diffuse reflectance infrared spectroscopy (DRIFTS) with transient experiments indicated that more nitrates and ammonia species formed on Pd/TiO2-R. For Pd/TiO2-R, bridging, mondentate, and bidentate nitrates served as active NO x adsorbed species at all the investigated reaction temperatures. Ammonia species that originated from the reduction of active NO x species were highly active intermediates, which can react with active NO x species to form N2 and H2O. However, for the Pd/TiO2-A catalyst, bridging and monodentate nitrates were active NO x adsorbed species at 75 °C. The reaction pathway at 225 °C facilitates the reaction between adsorbed NO2 and spiltover hydrogen. From the results of valence band X-ray photoelectron spectroscopy (VBXPS) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS), it could be deduced that the photogenerated holes of both Pd/TiO2 catalysts could activate NO and hydrogen. Moreover, the electrons in the conduction band of the Pd/TiO2-R catalyst had stronger reduction ability, which could combine with O2 to form •O2 –. All these results provided a new insight into the understanding of photothermal synergism in heterogeneous catalysis.

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Selective catalytic reduction of NO by H2 over Pd/TiO2 catalyst

Cited by 25 publications

References 42 publications

Y-Modified MCM-22 Supported PdOx Nanocrystal Catalysts for Catalytic Oxidation of Toluene

Y-Modified MCM-22 Supported PdOx Nanocrystal Catalysts for Catalytic Oxidation of Toluene

Unraveling the Promotional Effect of Co on the Pd/TiO₂ Catalyst for H₂-SCR of NO_x in the Presence of Oxygen

Photothermal Synergism on Pd/TiO₂ Catalysts with Varied TiO₂ Crystalline Phases for NO_x Removal via H₂-SCR: A Transient DRIFTS Study

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Selective catalytic reduction of NO by H2 over Pd/TiO2 catalyst

Cited by 25 publications

References 42 publications

Y-Modified MCM-22 Supported PdOx Nanocrystal Catalysts for Catalytic Oxidation of Toluene

Y-Modified MCM-22 Supported PdOx Nanocrystal Catalysts for Catalytic Oxidation of Toluene

Unraveling the Promotional Effect of Co on the Pd/TiO2 Catalyst for H2-SCR of NOx in the Presence of Oxygen

Photothermal Synergism on Pd/TiO2 Catalysts with Varied TiO2 Crystalline Phases for NOx Removal via H2-SCR: A Transient DRIFTS Study

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Unraveling the Promotional Effect of Co on the Pd/TiO₂ Catalyst for H₂-SCR of NO_x in the Presence of Oxygen

Photothermal Synergism on Pd/TiO₂ Catalysts with Varied TiO₂ Crystalline Phases for NO_x Removal via H₂-SCR: A Transient DRIFTS Study