Victor Charles

Bio: Victor Charles is an academic researcher from Modibbo Adama University of Technology, Yola. The author has contributed to research in topics: Catalysis & Overpotential. The author has an hindex of 2, co-authored 8 publications receiving 13 citations. Previous affiliations of Victor Charles include Chinese Academy of Sciences.

A review on CO oxidation, methanol synthesis, and propylene epoxidation over supported gold catalysts

Abstract: Abstract The aim of this general review is to give an overview of the reaction pathways involving the transformation of carbon monoxide (CO), methanol synthesis and propylene epoxidation using gold (Au) and gold supported clusters. Over the catalyst system of Nano-gold (Au/SiO2), the process of methane to methanol was also highlighted. A reaction mechanism proposed, indicated that molecular oxygen was consumed in the oxidation–reduction cycle. Consequently, methane oxidation to methanol can be achieved as a green chemical process. The system can also be used in other green chemical processes of liquid phase or gas phase oxidations. Methanol is expected to be a potential solution to the partial deployment of fossil source-based economies. Moreover, it is a recognized energy carrier that is better than other alternatives in terms of transportation, storage and reuse. New or improved catalysts for methanol production are likely to be discovered in the near future.

CoOx/UiO-66 and NiO/UiO-66 heterostructures with UiO-66 frameworks for enhanced oxygen evolution reactions

Abstract: The water oxidation reaction involves a four electron–proton coupled process that is kinetically sluggish and has hindered the widespread application of water-splitting technology. Metal-MOF-coupled heterostructures serve as good OER electrocatalysts due to their endowed MOF frameworks and numerous transition metal active sites at the interface. In this study, a simple ultrasonic impregnation strategy was used to prepare CoOx/UiO-66-300 and NiO/UiO-66-300 heterostructures via the impregnation of Co and Ni ions into UiO-66 followed by roasting in air at 300 °C to obtain heterostructures with UiO-66-retained frameworks as revealed by SEM. The electrochemical results show that the respective impregnation successfully modulated the electronic charge at the interface of the heterostructures, leading to rapid electron transfer that enhanced the OER activity. CoOx/UiO-66-300 and NiO/UiO-66-300 heterostructures showed good oxygen evolution reaction activities of 283 mV and 291.6 mV, respectively, due to the retained UiO-66 framework, while CoOx/UiO-66-550 and NiO/UiO-66-550 heterostructures calcined at 550 °C showed a decrease in OER activities of 332.6 mV and 346.6 mV, respectively, due to the collapsed UiO-66 framework. This work gives insight into the development of heterostructures of MOF-retained frameworks for energy applications.

Solid-Solutions as Supports and Robust Photocatalysts and Electrocatalysts: A Review

Abstract: Abstract Some solid solutions have been strongly utilized over the years as good materials for the synthesis of electrocatalysts and photoctalysts. Sometimes, they are used as supports in order to improve electrocatalytic and photocatalytic properties. We show various achievements of solid solutions as good electrocatalysts, and also, good electrocatalysts support materials in oxygen reduction reaction (ORR), hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Also, we demonstrate various works utilizing solid solutions as good photocatalysts, and good photocatalysts support materials in overall water splitting and carbon dioxide reduction. In all these reports, solid solutions proved to posses the necessary properties needed of any material as electrocatalysts and photocatalysts. In many cases, their use as catalysts supports recorded great improvements. X-ray photoelectron spectroscopy (XPS) was largely used to confirm the chemical environment of the results obtained, together with X-ray diffraction (XRD). In the electrochemical methods, cyclic voltammograms (CVA), chronoamperometry and rotating disk electrode (RDE), were also carried out. Linear sweep voltametry (LSV) curve was carried out in some cases to measure the current at a working electrode, and tables were shown for clear explanation. In addition, a photoluminescence spectrum (PL) was used to probe the electronic structure of the various solid solutions.

A review on particulate photocatalytic hydrogen production system: Progress made in achieving high energy conversion efficiency and key challenges ahead

Abstract: Photocatalytic water splitting is a sustainable and clean method to produce renewable hydrogen. The particulate photocatalytic water splitting system has been envisioned as an efficient and cost-effective solution for large-scale hydrogen production. Herein, we have reviewed the various existing particulate photocatalytic systems for hydrogen production via overall water splitting, as well as via photo-reforming of biomass-derived organic substances. The progress made in improving the apparent quantum efficiency and solar to the hydrogen conversion efficiency of existing photocatalysts is highlighted. The factors affecting the particulate photocatalytic water splitting system are summarized. Finally, some of the key limitations and future perspectives on large-scale hydrogen production are discussed.