http://max.materials.drexel.edu/wp-content/uploads/Halim_XPS_of_MXenes-2016.pdf

X-ray photoelectron spectroscopy of select multi-layered transition metal carbides (MXenes)

Nitrogen-doped titanium dioxide as visible-light-sensitive photocatalyst: designs, developments, and prospects.

Surface modification and enhanced photocatalytic CO2 reduction performance of TiO2: a review

High purity hydrogen has many applications one of which is in the hydrogen fuel cell industry. Hydrogen can be easily produced from water electrolysis; however, the most economical method is steam reforming of methane. This delivers a mixture of gaseous compounds from which hydrogen can be extracted. Besides various techniques such as pressure swing adsorption and cryogenic distillation, dense metal membranes offer an energy efficient and highly selective method for separating hydrogen from a hot gas mixture achieving high purity levels. This review article covers the fundamentals of hydrogen selective membranes for both the porous and dense kind. An in-depth look at dense and porous membranes is taken to establish their current development and a comparison is drawn between both types showing that dense metal membranes have the best hydrogen flux and selectivity. A variety of commercial dense metal membranes are compared revealing the Group V elements such as vanadium (V), niobium (Nb) and tantalum (Ta) to have the highest hydrogen permeability. A major limitation with these metals is their tendency to form a stable oxide layer under ambient conditions. Palladium (Pd) does not suffer this problem at typical membrane operating conditions and with relatively high hydrogen permeability is a suitable alternative as a dense metal membrane. Over the years it has been discovered that alloying Pd with elements such as silver (Ag), yttrium (Y) and copper (Cu) results in marked improvements in hydrogen permeability, mechanical durability and in some cases resistance to contamination by sulphur containing compounds. Nevertheless, there are still opportunities to improve the performance of the existing commercial Pd-based membranes by investigating the endless scope of unexplored Pd binary and ternary alloys.

Hydrogen selective membranes: A review of palladium-based dense metal membranes

Non-Pd BCC alloy membranes for industrial hydrogen separation

First principle calculations of the electronic and optical properties of pure and (Mo, N) co-doped anatase TiO2

Analysis and examination of data is performed in digital forensics. Nowadays computer is the major source of communication which can also be used by the investigators to gain forensically relevant information. Forensic analysis can be done in static and live modes. Traditional approach pro- vides incomplete evidentiary data, while live analysis tools can provide the investigators a more accurate and consistent picture of the current and pre- viously running processes. Many important system related information present in volatile memory cannot be effectively recovered by using static analysis techniques. In this paper, we present a critical review of static and live analysis approaches and we evaluate the reliability of different tools and tech- niques used in static and live digital forensic analysis.

/pdf/exploring-static-and-live-digital-forensics-methods-274vyebyso.pdf

Exploring Static and Live Digital Forensics: Methods, Practices and Tools

In this paper, the effects of Mo doping on the geometrical, electronic, optical, and photocatalytic properties of TiO2 have been investigated theoretically and experimentally. The density functional theory based calculations show that Mo doping creates impurity states (Mo 4d) below the conduction band of TiO2 and the Fermi level is pinned inside the conduction band verifying n-type doping nature of the Mo in TiO2, which enhances its visible light absorption. Anatase TiO2 particles with Mo contents of 0.08, 0.1, 0.5, 1.0, 1.5 and, 2.0 at.% were synthesized by hydrothermal method without any post heat treatment for crystallization. Experiment results show that Mo ions have been successfully doped into the TiO2 lattice. The morphology of TiO2 particles is nearly spherical and the grain size is uniformly distributed as about 10 nm. Synthesized sample with 0.1 at.% Mo doping concentration shows the best visible light photocatalytic activity due to the reduced band gap and improved electron-hole pairs separation. However, the photocatalytic activity of the sample with 2.0 at.% Mo is relatively low although its visible light absorption is the best among the samples. The enhanced recombination of electron-hole pairs caused by the excessive Mo doping concentration may account for it.

Mo-doped TiO2 with enhanced visible light photocatalytic activity: a combined experimental and theoretical study.

Recently, substoichiometric titanium nitrides (x = 0.45 and 0.61) and carbonitrides (x = y = 0.35) have been synthesized by multiple-energy ion implantation at the surface of pure titanium. Changes in the binary and ternary alloy electronic properties versus defect impurity and vacancy concentrations have been studied by means of core Ti 2p and valence x-ray photoemission spectra (XPS). Moreover, self-consistent tight-binding linear-muffin-tin-orbital calculations with empty spheres in place of the missing nitrogen and/or carbon atoms give, among other information, the total density of occupied states, for comparison with the observed valence XPS value.

http://iopscience.iop.org/article/10.1088/0953-8984/9/40/012/pdf

Band structure of substoichiometric titanium nitrides and carbonitrides: spectroscopical and theoretical investigations

To employ TiO2 as an efficient photocatalyst, high reactivity under visible light and improved separation of photoexcited carriers are required. An effective co-doping approach is applied to modify the photocatalytic properties of TiO2 by doping vanadium (transition metal) and yttrium (rare earth element). V and/or Y codoped TiO2 was prepared using hydrothermal method without any post calcination for crystallization. Based on density functional theory, compensated and noncompensated V, Y codoped TiO2 models were constructed and their structural, electronic, and optical properties were calculated. Through combined experimental characterization and theoretical modeling, V, Y codoped TiO2 exhibited high absorption coefficient with enhanced visible light absorption. All the prepared samples showed pure anatase phase and spherical morphology with uniform particle distribution. Electronic band structure demonstrates that V, Y codoping drastically reduced the band gap of TiO2. It is found that both the doped V and Y exist in the form of substitutional point defects replacing Ti atom in the lattice. The photocatalytic activity, evaluated by the degradation of methyl orange, displays that the codoped TiO2 sample exhibits enhanced visible light photocatalytic activity. The synergistic effects of V and Y drastically improved the Brunauer-Emmett-Teller specific surface area, visible light absorption, and electron-hole pair's separation leading to the enhanced visible light catalytic activity.

Matiullah Khan

Papers

First principle calculations of the electronic and optical properties of pure and (Mo, N) co-doped anatase TiO2

Exploring Static and Live Digital Forensics: Methods, Practices and Tools

Mo-doped TiO2 with enhanced visible light photocatalytic activity: a combined experimental and theoretical study.

Band structure of substoichiometric titanium nitrides and carbonitrides: spectroscopical and theoretical investigations

Cationic (V, Y)-codoped TiO2 with enhanced visible light induced photocatalytic activity: A combined experimental and theoretical study