Organic Matter Characterization of Shale Rock by X-ray Photoelectron Spectroscopy: Adventitious Carbon Contamination and Radiation Damage

A detailed characterization of the organic matter in sediments gives a key parameter for the correct evaluation ofthe petroleum generation potential of a source rock and its modeling in an oil system. To understand the features of the organic matter stored in source rocks, a wide variety of routine techniques are used. Those techniques are mostly destructive, timeconsuming,and are not necessarily suitable for all the shale rocks. Thus, new technologies are being explored. XPS is a solid state,nondestructive, and direct method. It can be used to directly probe the speciation of organic carbon in sedimentary materials byC1s spectra measurements. In this work, we demonstrated that a heterogeneous layer of adventitious carbon (AC) is always present on the rock. This layer significantly altered the features of the organic compound fingerprint, which is measured by XPS of C1s. To acquire a reliable organic matter composition of a rock from XPS spectra it is necessary to remove the AC layer by sputtering it with Ar+. Further, the sputtering damage of the organic matter appears after an hour of radiation, and rocks become contaminated again during storage in the UHV chamber. The radiation damage by X-ray is also relevant in the XPS measurementof a rock. This damage is associated with an increment of AC contamination on the rock surface. To minimize this side effect,C1s spectra have to be measured immediately after the sputtering conditioning step. Thus, we developed a method for XPS measurements taking into account the AC contamination and radiation damage. We consider that the proposed method for outcrop shales can be applied to a wide range of rock sampling types, such as cuttings, damaged crowns, and so forth.Fil: Canneva, Antonela. YPF - Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Giordana, Iván Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. YPF - Tecnología; ArgentinaFil: Erra, Georgina. YPF - Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Calvo, Alejandra. YPF - Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Analytical applications of Cu@PtPd/C nanoparticles for the quantification of hydrogen peroxide

This work reports a non-enzymatic amperometric sensor for hydrogen peroxide based on the use of a glassy carbon composite electrode modified with core-shell Cu@PtPd/C nanoparticles. Cu@PtPd/C presents an important electrocatalytic activity towards hydrogen peroxide reduction. The comparison of the sensitivities and the charge transfer resistances for hydrogen peroxide at the glassy carbon composite electrode modified with 5.0% w/w Pt/C, Pd/C, Pd/C + Pt/C and Cu@PtPd/C demonstrate a clear synergism on the catalytic reduction of hydrogen peroxide at −0.100 V when having Pt, Pd and Cu incorporated in the core-shell nanostructure. The best compromise between sensitivity, reproducibility and response time was reached with 20.0% w/w Cu@PtPd/C. For the selected sensor (glassy carbon composite electrode containing 20.0% w/w GCPE/Cu@PtPd/C) the analytical parameters are highly competitive compared to similar devices reported in the last years, with a linear relationship between current and hydrogen peroxide concentration between 5.0 × 10−6 and 2.5 × 10−4 M, sensitivity of (5.30 ± 0.09) × 105 μAM−1 cm−2 (r2 = 0.998) and detection limit of (3.7 ± 0.5) × 10−7 M. The resulting sensing platform was successfully used for the quantification of hydrogen peroxide in a mouth-wash sample.Fil: Gutierrez, Fabiana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Giordana, Iván Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Fuertes, Valeria Cintia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Montemerlo, Antonella Evelin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Sieben, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; ArgentinaFil: Alvarez, Andrea Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; ArgentinaFil: Rubianes, María Dolores. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Rivas, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentin