Zhi-Lin Cheng

Preparation of oleic diethanolamide-capped copper borate/graphene oxide nanocomposites and their tribological properties in base oil

Graphene oxide (GO) nanosheets were decorated with copper borate (CuB) nanoparticles via a liquid phase-based ultrasonic-assisted stripping method to afford CuB/GO nanocomposites. The as-prepared nanocomposites were characterized using FT-IR, XRD, Raman, UV-vis, TEM and AFM techniques, revealing CuB nanoparticles anchored on the surface of GO nanosheets. To inhibit the agglomeration and improve the dispersion stability of the nanocomposites in the base oil, the CuB/GO nanocomposites were modified with oleic diethanolamide (OD), to obtain oleic diethanolamide-capped copper borate/graphene oxide nanocomposites (OD-CuB/GO). The tribological properties of these nanocomposites, when used as an additive in base oils with different viscosities, were evaluated with a four-ball friction and wear tester. The results showed that when the OD-CuB/GO nanocomposites were added into the base oil at a mass fraction of up to 4.0%, the friction coefficient and wear scar diameter of the OD-CuB/GO-based oil were respectively about 43.6% and 49.3% lower than those of the base oil. This indicates that the OD-CuB/GO nanocomposites can significantly improve the tribological properties of the base oil and possess a good anti-wear ability and load-carrying capacity.

Study on adsorption of rhodamine B onto Beta zeolites by tuning SiO 2 /Al 2 O 3 ratio

The exploration of the relationship between zeolite composition and adsorption performance favored to facilitate its better application in removal of the hazardous substances from water. The adsorption capacity of rhodamine B (RB) onto Beta zeolite from aqueous solution was reported. The relationship between SiO2/Al2O3 ratio and adsorption capacity of Beta zeolite for RB was explored. The structure and physical properties of Beta zeolites with various SiO2/Al2O3 ratios were determined by XRD, FTIR, TEM, BET, UV-vis and so on characterizations. The adsorption behavior of rhodamine B onto Beta zeolite matched to Langmuir adsorption isotherm and more suitable description for the adsorption kinetics was a pseudo-second-order reaction model. The maximum adsorption capacity of the as-prepared Beta zeolite with SiO2/Al2O3 = 18.4 was up to 27.97mg/g.

Preparation and Solar Light Photocatalytic Activity of N-Doped TiO2-Loaded Halloysite Nanotubes Nanocomposites

A novel method to prepare N-doped TiO2-loaded halloysite nanotubes (N-TiO2/HNTs) nanocomposites was achieved by using the chemical vapor deposition in autoclave. The N-TiO2/HNTs nanocomposites obtained by the different form of the doping N source were studied through a series of characterizations. The XRD, SEM, and TEM characterizations verified the anatase structure of TiO2 nanoparticles with the size of ca.20nm loaded on the outer surface of HNTs. The UV-vis characterization of the N-TiO2/HNTs presented a further red-shift compared to the pure N-TiO2 nanoparticles.. The XPS characterizations confirmed the N element doped into the crystal structure of TiO2 nanoparticles. The photocatalytic activities of N-TiO2/HNTs nanocomposites prepared were evaluated by degradation of phenol at room temperature under simulated solar light irradiation.

Preparation and photoelectrocatalytic performance of N-doped TiO2/NaY zeolite membrane composite electrode material

A novel composite electrode material based on a N-doped TiO2-loaded NaY zeolite membrane (N-doped TiO2/NaY zeolite membrane) for photoelectrocatalysis was presented. X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible (UV-vis) and X-ray photoelectron spectroscopy (XPS) characterization techniques were used to analyze the structure of the N-doped TiO2/NaY zeolite membrane. The XRD and SEM results verified that the N-doped TiO2 nanoparticles with the size of ca. 20 nm have been successfully loaded on the porous stainless steel-supported NaY zeolite membrane. The UV-vis result showed that the N-doped TiO2/NaY zeolite membrane exhibited a more obvious red-shift than that of N-TiO2 nanoparticles. The XPS characterization revealed that the doping of N element into TiO2 was successfully achieved. The photoelectrocatalysis performance of the N-doped TiO2/NaY zeolite membrane composite electrode material was evaluated by phenol removal and also the effects of reaction conditions on the catalytic performance were investigated. Owing to exhibiting an excellent catalytic activity and good recycling stability, the N-doped TiO2/NaY zeolite membrane composite electrode material was of promising application for photoelectrocatalysis in wastewater treatment.

Preparation of N-doped ZnO-loaded halloysite nanotubes catalysts with high solar-light photocatalytic activity

N-doped ZnO nanoparticles were successfully assembled into hollow halloysite nanotubes (HNTs) by using the impregnation method. The catalysts based on N-doped ZnO-loaded HNTs nanocomposites (N-doped ZnO/HNTs) were characterized by X-ray diffraction (XRD), transmission electron microscopy-energy dispersive X-ray (TEM-EDX), scanning electron microscopy-energy dispersive X-ray (SEM-EDX), UV-vis and Fourier transform infrared spectroscopy (FT-IR) techniques. The XRD pattern showed ZnO nanoparticles with hexagonal structure loaded on HNTs. The TEM-EDX analysis indicated ZnO particles with the crystal size of ca.10 nm scattered in hollow structure of HNTs, and furthermore the concentration of N atom in nanocomposites was up to 2.31%. The SEM-EDX verified most of N-ZnO nanoparticles existing in hollow nanotubes of HNTs. Besides containing an obvious ultraviolet absorbance band, the UV-vis spectra of the N-doped ZnO/HNTs catalysts showed an available visible absorbance band by comparing to HNTs and non-doped ZnO/HNTs. The photocatalytic activity of the N-doped ZnO/HNTs catalysts was evaluated by the degradation of methyl orange (MO) solution with the concentration of 20 mg/L under the simulated solar-light irradiation. The result showed that the N-doped ZnO/HNTs catalyst exhibited a desirable solar-light photocatalytic activity.

Novel Preparation of Calcium Borate/Graphene Oxide Nanocomposites and Their Tribological Properties in Oil

The calcium borate/graphene oxide (CB/GO) nanocomposites have been successfully prepared by a liquid phase-based ultrasonic-assisted stripping method, which were subsequently explored as lubricant additive. The structure and morphology of the as-prepared nanocomposites were characterized by FT-IR, XRD, Raman, TEM, EDS and TGA, revealing that CB nanoparticles were uniformly loaded on GO surfaces. The nanocomposites were highly dispersed into the base oil by sand milling. The tribological properties of CB/GO nanocomposites as lubricating oil additive were investigated using a four-ball machine, and the wear scar surfaces were observed by the 3D Laser Scanning Microscope. The results indicated that CB/GO nanocomposites were of excellent antifriction, antiwear ability and load-carrying capacity.

High-performance PTFE nanocomposites based on halloysite nanotubes

Abstract Halloysite nanotubes (HNTs)/polytetrafluoroethylene (PTFE) nanocomposites were prepared by the cold compression moulding method. The effects of addition of HNTs (HNTs ‘filling’) on the performances of PTFE were explored using X-ray diffraction, Fourier Transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis which showed that HNTs were well dispersed in the PTFE matrix by means of physical mixing at lower contents of 2-5 wt.%; the introduction of HNTs into PTFE could improve the heat stability of the PTFE. Furthermore, the mechanical and tribological performances of the nanocomposites were measured to examine the filling effect. The tensile strength of the HNTs/PTFE nanocomposites at 2-5 wt.% HNTs content increased by ∼3.5% while their wear rates decreased by 55-90% relative to pure PTFE, clear proof of the filling effect of HNTs with a high aspect ratio.

A study on synergistic reinforcing effect of halloysite nanotubes/diatomite mixture-filled polymer (PP and PA6) composites

ABSTRACT In this paper, the nanotubular halloysite nanotubes (HNTs)/disc-shaped diatomite mixture (HD) was used to study the synergistic reinforcing effect of the filler in polymer matrix (PP and PA6). The structure of the HNTs/diatomite mixture filler-filled polymer composites with different proportions of HNTs/diatomite was determined by XRD and SEM. The mechanical performance of the composites was extensively investigated. The results indicated that the HNTs/diatomite mixture filler with different shapes could significantly reinforce the mechanical performance of polymer regardless of whatever it was filled in — PP or PA6. The synergistic reinforcing effect of HNTs/diatomite mixture filler in polymer matrix was verified.

Preparation and tribological properties of oleic acid-decorated MoS2 nanosheets with good oil dispersion

Abstract In this paper, the self-made two-dimensional MoS2 nanosheets with five-layer thickness were attempted to be modified with oleic acid (OA) with a simple one-step route, denoted OA-MoS2. The OA-MoS2 nanosheets were confirmed by a series of characterizations. The results showed that OA molecules could chemically seal MoS2 nanosheets through C-S bonds, which significantly improved the dispersibility and stability of MoS2 nanosheets in base oil. The OA-MoS2 nanosheets possessed better dispersibility in base oil and could maintain the stability in oil up to 96 h. Furthermore, the tribological properties of OA-MoS2 nanosheets as an additive in base oil were completely studied through a ball-on-ball configuration four-ball testing machine. The experimental results showed that the average friction coefficient and average wear scar diameter of the 0.04 wt.% OA-MoS2-based oil were decreased by about 41.2% and 17.1% as compared to base oil, respectively. In addition, its extreme pressure performance increased by about 13.0%. These results indicated that OA-MoS2 nanosheets exhibited better antifriction, antiwear and extreme pressure abilities in oil due to the desirable solved dispersibility. Graphical Abstract

HNTs-Templated Preparation of Carbon Nanorods by Hydrothermal Nanocasting Method

A novel method to prepare carbon nanorods through hydrothermal nanocasting method was presented using halloysite nanotubes (HNTs) as the template and polyvinyl alcohol (PVA) as the carbon source. This method involved in three steps, i.e . nanocasting PVA in HNTs, carbonization and etching removal of template. A series of characterization, such as XRD, FT-IR, SEM, TEM, Raman, XPS, SAED and N 2 adsorption-desorption were used to detect the formation and structure of the as-prepared carbon nanorods (CNRs). The CNRs with a 1D rod-like structure were of high specific surface area (408 m 2 ·g -1 ) and possessed typical mesoporous characterization.