The hydrogenation of CO2 to methanol is a viable alternative for mitigating greenhouse gases net emissions as well as a route for hydrogen storage and transportation. In this work, we...
Cadmium selenide was analyzed using x-ray photoelectron spectroscopy (XPS). The specimen is a powder purchased from Chemsavers. Sample was fixed to a stainless-steel sample holder with copper 3M TM double-sided adhesive tape. Survey spectra, Cd 3d, Se 3d, O 1s, Cd 3p, Cd MNN, Se LMM, Se 3p, C 1s, and Cd 4d core level along with the valence band spectra were recorded. Results point out a stoichiometry of 0.95 on surface.
Bismuth (III) acetate was analyzed using x-ray photoelectron spectroscopy (XPS). The specimen is a powder purchased from Sigma Aldrich. Sample was fixed to a stainless-steel sample holder with copper 3M TM double-sided adhesive tape. Survey spectra, Bi 4f, O 1s, C 1s, Bi 4d, Bi 5d, Bi 6s core levels and valence band spectra were acquired. Results showed how the elements in the structure of bismuth acetate are related.
The
study of the reactivity of catalysts requires one to assess
chemical kinetics and mechanisms in the absence of mass transport
artifacts. Despite the existence of models and criteria for assessing
the presence of mass transfer limitations during catalytic tests for
gas-phase reactions in isothermal fixed bed reactors, the literature
does not present straightforward protocols for performing the latter
calculations. In this work, we present a systematic protocol for the
calculations above. Particularly, we present protocols for estimating
the effectiveness factor for external and the Weisz-Prater number
for the internal mass transfer limitations. Data previously published
on the oxidation of propane over mixed vanadium–aluminum (hydr)oxides
was taken as a case study. Based on these protocols, we did a sensitivity
study of the models used for calculations. Results showed that the
model for calculating the effectiveness factor was poorly sensitive
to all the above modifications. Meanwhile, the Weisz-Prater number
was much more sensitive to the studied modifications, even reaching
deviations up to ∼200%.
A clean straightforward laser ablation method in deionized (DI) water is reported for the synthesis of Molybdenum (Mo) and Nickel (Ni) nanoparticles (NPs). The structural, morphological, and optical properties of the as-synthesized nanoparticles were investigated. Particle size was estimated to be less than 10 nm, the UV–vis spectra of the samples show the formation of H2MoO4 and NiO. The XRD results for the Ni sample show the presence of two phases, cubic nickel oxide, and an fcc metallic nickel phase, indicating the possible formation of Ni/NiO compound. The nanoparticles synthesized were used as precursors in the production of a NiMo/γ-Al2O3 catalyst. The textural and structural properties, chemical composition, and catalytic performance in a hydrodesulfurization (HDS) reaction are reported. The textural and structural properties results show the lack of pore-blocking due to the small sizes and the distribution of the metallic nanoparticles on the support. Chemical composition measured by XPS shows a ratio Ni/Mo of 1.34. Therefore, possibly Ni was deposited on Mo covering part of its active area, occupying active sites of Mo, removing its effective surface and resulting in a relatively low conversion of DBT (17%). A lower Ni/Mo ratio is required to improve the model system, which could be achieved by changing parameters at the production of the nanoparticles. The model system can also be further tuned by changing the size of the nanoparticles.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.