Yongxia Wang

One-step synthesis of sulfur doped graphene foam for oxygen reduction reactions

Sulfur doped graphene foam has been successfully synthesized by a simple solve-thermal method, which exhibited a much enhanced oxygen reduction reaction (ORR) catalytic activity as well as an especially high electrochemical stability, and would be a promising non-metal cathode catalyst for the ORR.

Dual‐Mesoporous ZSM‐5 Zeolite with Highly b‐Axis‐Oriented Large Mesopore Channels for the Production of Benzoin Ethyl Ether

Dual-mesoporous ZSM-5 zeolite with highly b axis oriented large mesopores was synthesized by using nonionic copolymer F127 and cationic surfactant CTAB as co-templates. The product contains two types of mesopores--smaller wormlike ones of 3.3 nm in size and highly oriented larger ones of 30-50 nm in diameter along the b axis--and both of them interpenetrate throughout the zeolite crystals and interconnect with zeolite microporosity. The dual-mesoporous zeolite exhibits excellent catalytic performance in the condensation of benzaldehyde with ethanol and greater than 99 % selectivity for benzoin ethyl ether at room temperature, which can be ascribed to the zeolite lattice structure offering catalytically active sites and the hierarchical and oriented mesoporous structure providing fast access of reactants to these sites in the catalytic reaction. The excellent recyclability and high catalytic stability of the catalyst suggest prospective applications of such unique mesoporous zeolites in the chemical industry.

AMOEBA-I: a shape-shifting modular robot for urban search and rescue

This work intends to enhance the mobility and flexibility of a tracked mobile robot through changing its shape in unstructured environments. A shape-shifting mobile robot, AMOEBA-I, has been developed. With three tracked modules, AMOEBA-I has nine locomotion configurations and three of them are symmetrical configurations. The key advantage of this design over other mobile robots is its adaptability and flexibility because of its various configurations. It can change its configuration fluently and automatically to adapt to different environments or missions. A modularized structure of the control system is proposed and designed for AMOEBA-I to improve the fault tolerance and substitutability of the system. The strategies of cooperative control, including cooperative shape shifting, cooperative turning and cooperative obstacle negotiation, have been proposed to improve the capability of shape shifting, locomotion and obstacle negotiation for AMOEBA-I. A series of experiments have been carried out, and demonstrated that such a structure possesses excellent mobility and high flexibility under various urban environments including stairs, a narrow space, an obstacle, uneven debris and an underground garage. Being small, portable, and remotely controlled, AMOEBA-I has potential applications in areas such as urban search and rescue and environment reconnaissance.

CURRENT RESEARCH, KEY PERFORMANCES AND FUTURE DEVELOPMENT OF SEARCH AND RESCUE ROBOT

A survey of the research status for search and rescue robots in Japan,USA,China,and other countries is provided. According to current research,the experience,and the lessons learned from application,there are four key performances for search and rescue robot,which are,survivability,mobility, sensing,communicability,and operability.It is proved that, research of search and rescue robot is converted to practice from experiment gradually,Multi-technique fusion and multi-agent intelligent network are considered to be the future development requirement of the search and rescue robot.Dis- aster prevention,disaster reduction,and disaster rescue are important parts of the national public safety.And they are also crucial issues in the safety of citizens and their estates. Search and rescue robotic technique is an urgently needed, strategic,and core technique for national development.It will have important and strategic effect on the national economy and the national safety.

One-step replication and enhanced catalytic activity for cathodic oxygen reduction of the mesostructured Co3O4/carbon composites

Mesostructured Co3O4/C composites of high surface area have been synthesized via a one-step replica route by co-nanocasting cobalt and carbon precursors into mesoporous silica, in which the Co3O4 nanoparticles are homogeneously dispersed in the mesoporous structure of carbon substrates. The mesostructured composites showed relatively high catalytic activities for oxygen reduction reaction (ORR), and that with a Co loading content of 4.3 at% exhibited the best electrochemical performance for ORR. The relatively high catalytic activity is attributed to the effects of the redox couples (Co(3+)/Co(2+)) together with the contribution from the conductive mesoporous carbon substrate.

Highly active half-sandwich chromium( iii ) catalysts bearing bis(imino)pyrrole ligands for ethylene (co)polymerization

A series of half-sandwich Cr(III) complexes bearing bis(imino)pyrrole ligands, Cp′[2,5-C4H2N(CHNAr)2]CrCl [Cp′ = C5H5, Ar = C6H5 (2a), 2,6-Me2C6H3 (2b), 2,6-iPr2C6H3 (2c), C6F5 (2d); Cp′ = C5Me5, Ar = C6H5 (3a), 2,6-iPr2C6H3 (3c)] were synthesized with good yields. The complexes were characterized by FTIR and mass spectrometry in addition to elemental analyses. X-ray structural analyses for 2a–c showed that the Cr complexes have a pseudo-octahedral coordination environment with a three-legged “piano stool” geometry. One of the imino nitrogen atoms is coordinated with the Cr metal. On activation with methylaluminoxane, the Cp-based complexes showed high catalytic activities for ethylene polymerization. High molecular weight polymers with unimodal molecular weight distributions were obtained, indicating that the nature of the polymerization was single site. The copolymerization of ethylene with norbornene by the pre-catalysts 2a–d was also explored in the presence of methylaluminoxane. The catalytic activity, co-monomer incorporation and the properties of the resultant polymers can be controlled over a wide range by tuning the catalyst structures and reaction parameters.

Hollow mesoporous carbon cubes with high activity towards the electrocatalytic reduction of oxygen.

Hollow-structured mesoporous carbon cubes (HMCCs) have been successfully synthesized from carbon dioxide by a facile approach based on thermal reduction of magnesium. The approach is economical and applicable to large-scale synthesis. Notably, pyrrole-type nitrogen species are doped into the HMCCs during the synthesis in situ, that is, without introducing a nitrogen-containing precursor. A formation mechanism of the HMCCs is proposed, and formation of the structure is attributed to MgO templates generated in situ. Furthermore, the HMCCs are demonstrated to be a promising alternative to commercial Pt/C fuel-cell catalysts for the electrochemical oxygen reduction reaction.

One-step hydrothermal synthesis of nitrogen-doped carbon nanotubes as an efficient electrocatalyst for oxygen reduction reactions.

A high amount of heteroatom doping in carbon, although favorable for enhanced density of catalytically active sites, may lead to substantially decreased electroconductivity, which is necessary for the electrochemical oxygen reduction reaction. Herein, a relatively low amount of nitrogen was successfully doped into carbon nanotubes (CNTs) by a hydrothermal approach in one step, and the synthesized nitrogen-doped CNT (CNT-N) materials retained most of the original, excellent characteristics, such as the graphitic structure, tubular morphology, and high surface area, of CNTs. The resultant CNT-N materials, although containing a relatively low amount of nitrogen doping, exhibited high electrocatalytic ORR activity, comparable to that of 20 wt% Pt/C; long durability; and, more importantly, largely inhibited methanol crossover effect.

Amorphous Fe2+-rich FeOx loaded in mesoporous silica as a highly efficient heterogeneous Fenton catalyst

A simple physical-vapor-infiltration (PVI) method using ferrocene as the iron source, has been developed to load FeOx into the pore channels of mesoporous silica SBA-15. The obtained FeOx/SBA-15 composite has a high loading amount of FeOx (e.g. 26.64 wt% Fe content obtained at PVI duration 17 h and calcination temperature 450 °C) but unblocked pore channels thanks to the unique preparation strategy. The FeOx species are amorphous, rich of Fe(2+) and have been highly dispersed as a nanocoating onto the pore channel surface. The FeOx/SBA-15 composite was used as a heterogeneous Fenton catalyst to degrade Acid orange 7 (AO7). It showed a high catalytic activity and degradation efficiency, which was attributed to the high proportion of Fe(2+) in the amorphous FeOx and their favorable adsorption capability for the dye. The influences of the PVI duration, the calcination temperature and the Fenton reaction conditions (FeOx/SBA-15 dosages, H2O2 dosages and initial pH value) on the catalytic activity were investigated in detail.

Synergetic Catalytic Effects in Tri-Component Mesostructured Ru–Cu–Ce Oxide Nanocomposite in CO Oxidation

This work focuses on probing the synergetic catalytic effects in mesostructured tri‐component Ru–Cu–Ce oxides in CO oxidation reaction. The crystallized nanocomposites with RuO2 and CuO nanoparticles dispersed homogeneously in the pore network of mesoporous CeO2 were synthesized by the nanocasting replication method. The greatly enhanced catalytic activity was achieved by CuO incorporating in mesoporous CeO2, and further by RuO2 incorporating in the mesostructure of CuO/CeO2. Two types of synergetic catalytic mechanisms have been preliminarily proposed to be copresent in the system: CeO2 activation by CuO through generating oxygen vacancies at CeO2/CuO interface and the CeO2 surface nearby, which consequently activate the oxygen species (O*) and enhance the CO oxidation activity of the bi‐metal CuCe oxide, and the simultaneous adsorption of CO molecules and their activation in parallel on the active surface of RuO2, which results in further elevated catalytic activity.