In view of important role of inducing and manipulating the magnetism in two-dimensional materials for the development of low-dimensional spintronic devices, the influences of strain on electronic structure and magnetic properties of commonly observed vacancies doped monolayer MoS2 are investigated using first-principles calculations. It is shown that unstrained VS, VS2, and VMoS3 doped monolayer MoS2 systems are nonmagnetic, while the ground state of unstrained VMoS6 doped system is magnetic and the magnetic moment is contributed mainly by six Mo atoms around VMoS6. In particular, tensile strain can induce magnetic moments in VS, VS2, and VMoS3 doped monolayer MoS2 due to the breaking of Mo–Mo metallic bonds around the vacancies, while the magnetization induced by VMoS6 can be effectively manipulated by equibiaxial strain due to the change of Mo–Mo metallic bonds around VMoS6 under strains.

Carbon dioxide hydrogenation to CO via the reverse water gas shift (RWGS) reaction is one route to integrate CO 2 utilization into the chemical industry. TiO 2 supported Cu catalysts are known to be active for RWGS, but Cu is shown here to behave differently on TiO 2 nanotubes (TiNT) vs TiO 2 nanoparticles (TiNP). Whereas nanoparticle supports give low rates that are hardly changed by added Cu, the nanotube supports yield much higher activity and three distinct behaviors as the Cu surface density increases. At low surface densities (0.3 Cu/nm 2), active Cu-O-Ti sites are created that have low apparent activation energies. At high surface densities (6 Cu/nm 2), Cu nanoparticles on TiNT are formed, and reaction barriers are lowered when both Cu and TiNT surfaces are accessible. At intermediate surface densities, metallic Cu domains are engulfed by a TiOx overlayer formed during H 2 pretreatment, akin to those formed by classical strong metal support interactions (SMSI). These reduced layers are markedly more active for RWGS than the initial TiNT surfaces, but have similar activation barriers, which are higher than those for which both Cu and TiNP surfaces are exposed. These catalytic findings are supported by computational modeling, in situ IR, UV-visible, and X-ray absorption spectroscopies, and they provide insight into an important reaction for CO 2 utilization.

We study the Raman spectroscopy of neutral iodine molecules confined in the channels of zeolite AlPO4-5 (AFI) and AlPO4-11 (AEL) crystals, which shows that the molecular vibration states are significantly modified by the confinements from the nanosize channels. An iodine molecule trapped in the AEL crystal has an effective internuclear potential close to an ideal harmonic oscillator, while that in the AFI crystal behaves similarly to that in free space. The results are further confirmed by measuring the temperature dependence of Raman spectral width.