A Highly Effective Catalyst of Sm-MnO_<i>x</i> for the NH₃‑SCR of NO_<i>x</i> at Low Temperature: Promotional Role of Sm and Its Catalytic Performance

Sm-Mn mixed oxide catalysts prepared by the coprecipitation method were developed, and their catalytic activities were tested for the selective catalytic reduction (SCR) of NO with ammonia at low temperature. The results showed that the amount of Sm markedly influenced the activity of the MnO_<i>x</i> catalyst for SCR, that the activity of the Sm-Mn mixed oxide catalyst exhibited a volcano-type tendency with an increase in the Sm content, and that the appropriate mole ratio of Sm to Mn in the catalyst was 0.1. In addition, the presence of Sm in the MnO_<i>x</i> catalyst can obviously enhance both water and sulfur dioxide resistances. The effect of Sm on the physiochemical properties of the Sm-MnO_<i>x</i> catalyst were investigated by XRD, low-temperature N₂ adsorption, XPS, and FE-SEM techniques. The results showed that the presence of Sm in the Sm-MnO_<i>x</i> catalyst can restrain the crystallization of MnO_<i>x</i> and increase its surface area and the relative content of both Mn⁴⁺ and surface oxygen (O_S) on the surface of the Sm-MnO_<i>x</i> catalyst. NH₃-TPD, NO-TPD, and in situ DRIFT techniques were used to investigate the absorption of NH₃ and NO on the Sm-MnO_<i>x</i> catalyst and their surface reactions. The results revealed that the presence of Sm in the Sm_0.1-MnO_<i>x</i> catalyst can increase the absorption amount of NH₃ and NO on the catalyst and does not vary the SCR reaction mechanism over the MnO_<i>x</i> catalyst: that is, the coexistence of Eley–Rideal and Langmuir–Hinshelwood mechanisms (bidentate nitrate is the active intermediate), in which the Eley–Rideal mechanism is predominant

Effect of Ceria Crystal Plane on the Physicochemical and Catalytic Properties of Pd/Ceria for CO and Propane Oxidation

Ceria nanocrystallites with different morphologies and crystal planes were hydrothermally prepared, and the effects of ceria supports on the physicochemical and catalytic properties of Pd/CeO₂ for the CO and propane oxidation were examined. The results showed that the structure and chemical state of Pd on ceria were affected by ceria crystal planes. The Pd species on CeO₂-R (rods) and CeO₂-C (cubes) mainly formed Pd_<i>x</i>Ce_1–<i>x</i>O_2−σ solid solution with −Pd²⁺–O^2––Ce⁴⁺– linkage. In addition, the PdO_<i>x</i> nanoparticles were dominated on the surface of Pd/CeO₂-O (octahedrons). For the CO oxidation, the Pd/CeO₂-R catalyst showed the highest catalytic activity among three catalysts, its reaction rate reached 2.07 × 10^–4 mol g_Pd^–1 s^–1 at 50 °C, in which CeO₂-R mainly exposed the (110) and (100) facets with low oxygen vacancy formation energy, strong reducibility, and high surface oxygen mobility. TOF of Pd/CeO₂-R (3.78 × 10^–2 s^–1) was much higher than that of Pd/CeO₂-C (6.40 × 10^–3 s^–1) and Pd/CeO₂-O (1.24 × 10^–3 s^–1) at 50 °C, and its activation energy (<i>E</i>_a) was 40.4 kJ/mol. For propane oxidation, the highest reaction rate (8.08 × 10^–5 mol g_Pd^–1 s^–1 at 300 °C) was obtained over the Pd/CeO₂-O catalyst, in which CeO₂-O mainly exposed the (111) facet. There are strong surface Ce–O bonds on the ceria (111) facet, which favors the existence of PdO particles and propane activation. The turnover frequency (TOF) of the Pd/CeO₂-O catalyst was highest (3.52 × 10^–2 s^–1) at 300 °C and its <i>E</i>_a value was 49.1 kJ/mol. These results demonstrate the inverse facet sensitivity of ceria for the CO and propane oxidation over Pd/ceria

Demographic and clinical characteristics (Mean±SD) of the study population.

<p>Demographic and clinical characteristics (Mean±SD) of the study population.</p

The haplotype association among all 21 SNPs in the GLUT9 gene.

<p>The haplotype association among all 21 SNPs in the GLUT9 gene.</p

The associations in the distributions of genotypes and allele frequency for two polymorphisms (rs13124007 and rs6850166) in the GLUT9 gene in cases and controls.

<p>The associations in the distributions of genotypes and allele frequency for two polymorphisms (rs13124007 and rs6850166) in the GLUT9 gene in cases and controls.</p

Association between the polymorphisms (rs13124007 and rs6850166) and characteristics among gout patients.

<p>*The major allele was referred to as allele 1 and the minor allele as allele 2.</p>#<p>Hypertension was defined as systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg or receiving antihypertensivedrug treatment in a patient with a history of hypertension.</p> <p>Diabetes was defined on the basis of fasting blood glucose ≥7.0 mmol/l (126 mg/dl) or non-fasting blood glucose ≥11.1 mmol/l(200 mg/dl) and/or treatment of diabetes.</p>&<p>Obesity is defined as a BMI of 30 and above by World Health Organization (WHO).</p

Genotype distribution and allele frequencies of promoter of the human GLUT9 gene in cases and controls.

*<p>Novel SNP not reported in public database before.</p>#<p>The major allele was referred to as allele 1 and the minor allele as allele 2.</p