Construction of robust coupling interface between MoS2 and nitrogen doped graphene for high performance sodium ion batteries

As a layered inorganic material,MoS2 has recently attracted intensive attention as anode for sodium ion batteries(SIBs).However,this anode is plagued with low electronic conductivity,serious volume expansion and sluggish kinetics,resulting in capacity fading and poor rate performance.Herein,we develop an interface engineering strategy to substantially enhance the sodium storage performance of MoS2 by incorporating layered MoS2 into three dimensional N-doped graphene scaffold.The strong coupling-interface between MoS2 and N-doped graphene scaffold can not only stabilize the MoS2 structure during sodium insertion/extraction processes,but also provide plenty of anchor sites for additional surface sodium storage.The 3D MoS2@N-doped graphene composite as anode for SIBs performs an outstanding specific capacity of 667.3 mA h g^-1 at 0.2 A g^-1,a prolonged stability with a capacity retention of 94.4%after 140cycles and excellent rate capability of 445 mA h g^-1 even at a high rate of 10 A g^-1.We combined experiment and theoretical simulation to further disclose the interaction between MoS2 and N-doped graphene,adsorption and diffusion of sodium on the composite and the corresponding sodium storage mechanism.This study opens a new door to develop high performance SIBs by introducing the interface engineering technique.

Hydrogen Sensing Characteristics of ZnSnO_3 Micro-Particles Doped with Noble Metal Pd

Perovskite-type oxide ZnSnO_3 doped with 0.5 wt% Pd was prepared directly by a hydrothermal process,its crystal structure and ceramic microstructure were characterized by XRD and TEM,and the gas sensing properties were tested in static state.It is found that the sensors based on ZnSnO_3 micro-particles have good sensitivity and selectivity to H_2.Its sensitivity can be changed with working temperature;the sensitivity of the sensors to H_2 could arrive 21 times when the working temperature is 332℃.

Preparation and NO_2 Sensing Characteristics of LaFeO_3 Nanoparticles

LaFeO_3 nanoparticles were prepared by decomposing a precursor La[Fe(CN)_6]·4H_2O at 800℃,the precursor was synthesized by a coordination precipitation process at room temperature.The decomposing mechanism of the precursor was investigated by analyzing TG-DSC curves.Its crystal structure,particle size and ceramic microstructure were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM).Furthermore,the gas sensing properties were tested at static state.It can be shown that LaFeO_3 nanoparticles are highly crystallized after sintering at 800℃,the particle size is about 50 nm.The sensor based on LaFeO_3 nanoparticles shows remarkable sensitivity to NO_2.

Room-temperature chlorine gas sensor based on CdSnO_(3) synthesized by hydrothermal process

The perovskite-structure CdSnO_(3) was obtained by calcinating CdSnO_(3)·3H_(2)O precursor at 550℃,which was synthesized by hydrothermal process at 170℃for 16 h.The phase and microstructure of the obtained CdSnO_(3) powders were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The CdSnO_(3) powders exhibit uniformly cubic structure with side length of about 100 nm.The effects of working temperature and concentration of detected gas on the gas response were studied.The selectivity of chlorine gas against other gases and response-recovery time of the sensor were also investigated.The results reveal that the CdSnO_(3) gas sensor has enhanced sensing properties to 1-10 ppm chlorine gas at room temperature;the value of gas response can reach 1338.9 to 5 ppm chlorine gas.Moreover,the sensor shows good selectivity and quick response behavior(23 s)to chlorine gas,indicating its application in detecting chlorine gas at room temperature in the future.