Search for: All records

This study describes computer simulations of carbonization and graphite formation, including the effects of hydrogen, nitrogen, oxygen, and sulfur. We introduce a novel technique to simulate carbonization, ‘Simulation of Thermal Emission of Atoms and Molecules (STEAM)’, designed to elucidate volatile outgassing and density variations in the intermediate material during carbonization. The investigation analyzes the functional groups that endure through high-temperature carbonization and examines the graphitization processes in carbon-rich materials containing non-carbon impurity elements. The physical, vibrational, and electronic attributes of impure amorphous graphite are analyzed, and the impact of nitrogen on electronic conduction is investigated.

Commercial titanium dioxide is successfully plasma‐treated under ambient conditions for different periods, leading to reduced crystallite size and the creation of oxygen vacancies. Density functional theory‐based calculations reveal the emergence of additional localized states close to the conduction band, primarily associated with under‐coordinated titanium atoms in non‐stoichiometric titanium‐oxide systems. The plasma‐treated samples exhibit improved photocatalytic performance in the degradation of methylene blue compared to untreated samples. Moreover, the 4‐hour plasma‐treated photocatalyst demonstrates commendable stability and reusability. This work highlights the potential of cost‐effective plasma treatment as a simple modification technique to significantly enhance the photocatalytic capabilities of titanium‐oxide materials.

We investigate electronic transport properties of copper–graphene (Cu–G) composites using a density-functional theory (DFT) framework. Conduction in composites is studied by varying the interfacial distance of copper/graphene/copper (Cu/G/Cu) interface models. Electronic conductivity of the models computed using the Kubo–Greenwood formula shows that the conductivity increases with decreasing Cu–G distance and saturates below a threshold Cu–G distance. The DFT-based Bader charge analysis indicates increasing charge transfer between Cu atoms at the interfacial layers and the graphene with decreasing Cu–G distance. The electronic density of states reveals increasing contributions from both copper and carbon atoms near the Fermi level with decreasing Cu–G interfacial distance. By computing the space-projected conductivity of the Cu/G/Cu models, we show that the graphene forms a bridge to the electronic conduction at small Cu–G distances, thereby enhancing the conductivity.