Summary A valid 3D sandwich‐like architecture of highly conductive Ti3C2Tx nanosheets with efficient 2D polar adsorption surfaces was evenly intercalated into graphene oxide (GO) skeletons with strong bridging via modified liquid phase impregnation, followed by a novel photo‐synthetic nitrogen doping process (N‐RGO/Ti3C2Tx). This novel photo‐synthetic nitrogen doping method not only reduced the GO in a short time but also induced nitrogen doping into the composite easily. Within the rationally designed sandwich‐like architecture, Ti3C2Tx interacted with reduced GO to construct a 3D conductive layer structure while inhibiting mutual stacking, thereby facilitating fast ion/electron transport and strong chemisorption for polysulfides, and also effectively buffering the volume expansion of electrodes during the discharge. In addition, the moderate chemical modulation induced by nitrogen doping achieved abundant defects and active sites, thereby improving the chemical immobilization for polysulfides. As sulfur host, the N‐RGO/Ti3C2Tx sandwich‐like architecture with 76.4 wt% sulfur could deliver excellent electrochemical performance due to the synergy of the above‐mentioned merits. A superior reversible capacity of approximately 1180 mAh g−1 could be achieved over 200 cycles at 0.1 C. Even after cycling 200 times at 0.5 C, a high capacity of 850 mAh g−1 could still be obtained with a capacity retention of 82.5%. We rationally designed a novel structure and then used a facile photo‐synthetic nitrogen doping strategy for surface modification, thus offering a new idea for designing multifunctional sulfur host for high‐performance lithium‐sulfur batteries.
Cu3N/MoS2 composite films were prepared by magnetron sputtering under different preparation parameter, and their photocatalytic properties were investigated. Results showed that the composite films surface was uniform and had no evident cracks. When the sputtering power of MoS2 increased from 2 W to 8 W, the photocatalytic performance of the composite films showed a trend of increasing first and then decreasing. Among these films, the composite films with MoS2 sputtering power of 4 W showed the best photocatalytic degradation performance. The photocatalytic degradation rate of methyl orange at 30 min was 98.3%, because the MoS2 crystal in the films preferentially grew over the Cu3N crystal, thereby affecting the growth of the Cu3N crystal. The crystallinity of the copper nitride also increased. During photocatalytic degradation, the proper amount of MoS2 reduced the band gap of Cu3N, and the photogenerated electron hole pairs were easily separated. Thus, the films produces additional photogenerated electrons and promotes the degradation reaction of the composite films on methyl orange solution.
In this study, molybdenum disulfide (MoS2) film samples were prepared at different temperatures and annealed through magnetron sputtering technology. The surface morphology, crystal structure, bonding structure, and optical properties of the samples were characterized and analyzed. The surface of the MoS2 films prepared by radio frequency magnetron sputtering is tightly coupled and well crystallized, the density of the films decreases, and their voids and grain size increase with the increase in deposition temperature. The higher the deposition temperature is, the more stable the MoS2 films deposited will be, and the 200 °C deposition temperature is an inflection point of the film stability. Annealing temperature affects the structure of the films, which is mainly related to sulfur and the growth mechanism of the films. Further research shows that the optical band gaps of the films deposited at different temperatures range from 0.92 eV to 1.15 eV, showing semiconductor bandgap characteristics. The optical band gap of the films deposited at 200 °C is slightly reduced after annealing in the range of 0.71–0.91 eV. After annealing, the optical band gap of the films decreases because of the two exciton peaks generated by the K point in the Brillouin zone of MoS2. The blue shift of the K point in the Brillouin zone causes a certain change in the optical band gap of the films.
Transition-metal dichalcogenide (MoS 2 ) is gaining increasing attention as a promising highperformance material in practical applications because of its wide-range electrical properties. However, the effect of thermal annealing on the electrophysical characteristics of MoS 2 remains unclear. In this study, the physical and electrophysical properties of MoS 2 thin films were characterized by Hall effect measurements. Large-area and high-quality MoS 2 thin films were obtained by RF sputtering and then subjected to ex situ thermal annealing. As the thermal annealing temperature was increased, the crystallinity of the MoS 2 thin films improved and the corresponding Fermi level shifted toward the valence band. At thermal annealing temperatures above 900 °C, the conductivity type of the MoS 2 thin films changed from the intrinsic n-type to p-type due to the emergence of MoO 3 . In addition, the orientation of the Hall coefficient was indefinite under thermal annealing, implying the electrical transport anisotropy of the MoS 2 thin films, which can be attributed to the spin-orbit coupling of the exposed Mo atoms in the films with sulfur vacancies. Furthermore, the Hall mobility and carrier concentration of the annealed MoS 2 thin films were up to 4.40 cm 2 V −1 s −1 and 12.5×10 16 cm −3 , respectively, at a Hall testing temperature of 305 K and an external magnetic field of 0.5 T.
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