This paper describes the effects of temperature on the complex intermediate processes from the precursor to the fully-crystallized anatase TiO2 nanoparticles in hydrothermal synthesis. The anatase TiO2 nanoparticles were synthesized in a wide temperature range below 230°C. The composition, morphology, and methylene blue (MB) decoloration characteristics of the obtained products were investigated by X-ray diffraction, Fourier transform infrared spectroscope, X-ray photoelectron spectroscope, and scanning and transmission electron microscope. The dehydrating polycondensation of Ti(IV)-hydrates and the decomposition of (NH4)2Ti3O7 intermediates with the temperature increase lead to the direct formation of anatase TiO2 nanoparticles under the hydrothermal environments. The strong MB decoloration of the hydrothermal products obtained at the low (≤130°C) and high (≥180°C) temperatures are attributed to the adsorption of Ti(IV)-hydrates and the photocatalysis of anatase TiO2 nanoparticles, respectively.
LU HongBinZHOU YouZhenVONGEHR SaschaTANG ShaoChunMENG XiangKang
In this paper, we report a simple one-step thermal reducing method for synthesis of bimetallic Au@Pd nanoparticles with core-shell structures on the graphene surface. This new type of Au@Pd e G composites is characterized by transmission electron microscopy, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. It is found that Au@Pd nanoparticles with an average diameter of 11 nm are well dispersed on the graphene surface, and the Au core quantity as well as the Pd shell thickness can be quantitatively controlled by loading different amounts of metallic precursors, and the involved core-shell structure formation mechanism is also discussed. The ternary Pt/Au@Pd e G composites can also be synthetized by the subsequent Pt doping. The catalytic performance of Au@Pd e G composites toward methanol electro-oxidation in acidic media is investigated. The results show that Au@Pd e G composites exhibit higher catalytic activity, better stability and stronger tolerance to CO poisoning than Pd-G and Au-G counterparts.
We report the mechanical spectroscopy study of the cold-rolling induced dynamical behavior of crystalline defects in nanocrystalline (NC) nickel The results show that internal friction (IF) peaks in NC nickel can be induced by cold-rolling.An IF peak,originating from dislocation activity,occurs when the strain is in the range of 9.7- 32.8%.Two Bordoni peaks occur when the strain is 39.0% and an IF peak associated with deformation twinning appears when the strain is 42.6%.These results mean that deformation of NC nickel is mediated by different kinds of defects as the strain increases.
Today’s emergence of nano-micro hybrid structures with almost biological complexity is of fundamental interest.Our ability to adapt intelligently to the challenges has rami?cations all the way from fundamentally changing research itself,over applications critical to future survival,to posing globally existential dangers.Touching on speci?c issues such as how complexity relates to the catalytic prowess of multi-metal compounds,we discuss the increasingly urgent issues in nanotechnology also very generally and guided by the motto‘Bio Is Nature’s Nanotech’.Technology belongs to macro-evolution;for example integration with arti?cial intelligence(AI)is inevitable.Darwinian adaptation manifests as integration of complexity,and awareness of this helps in developing adaptable research methods that can?nd use across a wide range of research.The second half of this work reviews a diverse range of projects which all bene?ted from‘playful’programming aimed at dealing with complexity.The main purpose of reviewing them is to show how such projects bene?t from and?t in with the general,philosophical approach,proving the relevance of the‘big picture’where it is usually disregarded.
