Active and stable methane oxidation nano-catalyst with highly-ionized palladium species prepared by solution combustion synthesis

We report on the synthesis and testing of active and stable nano-catalysts for methane oxidation. The nano-catalyst was palladium/ceria supported on alumina prepared via a one-step solution-combustion synthesis (SCS) method. As confirmed by X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HTEM), SCS preparative methodology resulted in segregating both Pd and Ce on the surface of the Al 2 O 3 support. Furthermore, HTEM showed that bigger Pd particles (5 nm and more) were surrounded by CeO 2 , resembling a core shell structure, while smaller Pd particles (1 nm and less) were not associated with CeO 2 . The intimate Pd-CeO 2 attachment resulted in insertion of Pd ions into the ceria lattice, and associated with the reduction of Ce 4+ into Ce 3+ ions; consequently, the formation of oxygen vacancies. XPS showed also that Pd had three oxidation states corresponding to Pd0, Pd 2+ due to PdO, and highly ionized Pd ions (Pd (2+x)+ ) which might originate from the insertion of Pd ions into the ceria lattice. The formation of intrinsic Ce 3+ ions, highly ionized (Pd2+ species inserted into the lattice of CeO 2 ) Pd ions (Pd (2+x)+ ) and oxygen vacancies is suggested to play a major role in the unique catalytic activity. The results indicated that the Pd-SCS nano-catalysts were exceptionally more active and stable than conventional catalysts. Under similar reaction conditions, the methane combustion rate over the SCS catalyst was ~18 times greater than that of conventional catalysts. Full methane conversions over the SCS catalysts occurred at around 400 C but were not shown at all with conventional catalysts. In addition, contrary to the conventional catalysts, the SCS catalysts exhibited superior activity with no sign of deactivation in the temperature range between ~400 and 800 C. 2018 by the authors. Licensee MDPI, Basel, Switzerland.Acknowledgments: This paper was made possible by an NPRP Grant #6-290-1-059 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.Scopu

Synthesis, characterization and performance of Pd-based core-shell methane oxidation nano-catalysts

In this paper, a comparative investigation of the catalytic performances of Pd@TiO2 and Pd@CeO2, core-shells nanocatalysts supported over functionalized alumina, for application to methane oxidation is presented. The results indicated that the Pd@CeO2/SiO2.Al2O3 core-shell nanocatalyst exhibited higher activity and stability than the Pd@TiO2/SiO2.Al2O3 nanocatalyst. Complete combustion of methane over the Pd@CeO2/SiO2.Al2O3 nanocatalyst was achieved at about 400 ?C. By contrast, the maximum combustion of methane over the Pd@TiO2/SiO2.Al2O3 nanocatalyst was only attained at ?550 ?C. The Pd@TiO2/SiO2.Al2O3 nanocatalyst experienced deactivation, and a transient dip in methane conversion in the temperature region between 580 ?C and 750 ?C was also observed. The exceptional activity of the Pd@CeO2/SiO2.Al2O3 nanocatalyst was attributed to the intimate interaction between palladium (Pd) and ceria (CeO2) and efficient oxygen back-spillover at Pd and CeO2 interface resulting from the core-shell structure. ? 2018 Elsevier B.V.This paper was made possible by an NPRP Grant # 6-290-1-059 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors

The role of biomarkers as a diagnostic tool in some neoplasms of pet animals

Cancerous tumors are one of the main problems that cause of deaths in pet animals. The objective of this paper is to describe histopathological features of some neoplastic masses with confirmation using immunohistochemistry in pet animals.  Our study was done from May 2022 to August 2023 in Sharkia governorate, Egypt to correctly recognize 7 cases of pet animal neoplasms "5 cases of dogs and 2 queen case" based on histopathological and immunohistochemical findings.  The results revealed 2 cases of TVT in Penis with positive expressions for Iba2 and vimentin  , 1 Case of Sebaceous adenoma in Hock joint of male dog skin, 1 case of hepatoid carcinoma in perianal glands of male dog with positive immunolabelling for CK7  , 1 case of chondroblastic osteosarcoma  in A 4-year old, male, Great Dane dog  and 2 cases of queen with mammary gland adenocarcinoma with positive immunoreactivity for HER-2 and other mixed mammary neoplasm accompanied with sarcoma has positive staining for vimentin. It could be concluded that  the histopathological evaluations by H&E stain is the backbone method for neoplasms diagnosis and  using some  biomarkers added a confirmatory tools for these diagnosis

The role of biomarkers as a diagnostic tool in some neoplasms of pet animals

Cancerous tumors are one of the main problems that cause of deaths in pet animals. The objective of this paper is to describe histopathological features of some neoplastic masses with confirmation using immunohistochemistry in pet animals.  Our study was done from May 2022 to August 2023 in Sharkia governorate, Egypt to correctly recognize 7 cases of pet animal neoplasms "5 cases of dogs and 2 queen case" based on histopathological and immunohistochemical findings.  The results revealed 2 cases of TVT in Penis with positive expressions for Iba2 and vimentin  , 1 Case of Sebaceous adenoma in Hock joint of male dog skin, 1 case of hepatoid carcinoma in perianal glands of male dog with positive immunolabelling for CK7  , 1 case of chondroblastic osteosarcoma  in A 4-year old, male, Great Dane dog  and 2 cases of queen with mammary gland adenocarcinoma with positive immunoreactivity for HER-2 and other mixed mammary neoplasm accompanied with sarcoma has positive staining for vimentin. It could be concluded that  the histopathological evaluations by H&E stain is the backbone method for neoplasms diagnosis and  using some  biomarkers added a confirmatory tools for these diagnosis