Simin Yin

Facile synthesis of PbTiO3 truncated octahedra via solid-state reaction and their application in low-temperature CO oxidation by loading Pt nanoparticles

Perovskite PbTiO3 (PTO) nanocrystals with a truncated octahedral morphology have been prepared by a facile solid-state reaction. Pt nanoparticles preferentially nucleated on the {111} facet of PTO nanocrystals exhibit a remarkable low-temperature catalytic activity towards CO oxidation from a temperature as low as 30 °C and achieve 100% conversion at ∼50 °C.

Growth and Bending-Sensitive Photoluminescence of a Flexible PbTiO3/ZnO Nanocomposite

A brushlike PbTiO3 (PTO)/ZnO nanocomposite with ZnO nanowires (NWs) grown epitaxially on the surface of single-crystal ferroelectric tetragonal PTO NWs is successfully fabricated onto a flexible substrate via a two-step hydrothermal process. In this nanocomposite, a ZnO NW grew along [0001] on the (101) plane of the core PTO NW with a lattice mismatch of 1.06% to form an effective ferroelectric/semiconductor interface. It is found that the ultraviolet photoluminescence emission of the nanocomposite could be easily tuned by its bending curvatures at room temperature. This intriguing phenomenon can be understood by the bending-induced polarization field from the PTO NW, which could reduce the bending degree of the energy band of the ZnO NWs through the interface. Throughthe design of an effective interface, this kind of ferroelectric/semiconductor nanocomposite may find potential applications in sensor and piezophotonic nanodevices.

Facile synthesis and visible photocatalytic activity of single-crystal TiO2/PbTiO3 heterostructured nanofiber composites

Single-crystal TiO2/PbTiO3 nanofiber composites were prepared by a simple hydrothermal synthesis and annealing treatment at 650 °C, where pre-perovskite (PP) PbTiO3 (PTO) and tetrabutyl titanate (TBOT) were used as precursors. In the composites, anatase TiO2 nanorods grew on the surface of tetragonal perovskite (TP) PTO nanofibers and formed sharp TiO2/PbTiO3 interfaces, leading to single-crystal heterostructures. The as-synthesized heterostructured nanofiber composites exhibited excellent photocatalytic activity for degradation of methylene blue (MB) under visible light irradiation (λ > 400 nm). Especially, the composites TiO2/PbTiO3 TBOT: 0.4 mL showed the highest photocatalytic activity, and the degradation rate of MB was 0.02392 min−1. Such photocatalytic activity of the heterostructured nanofiber composites was supposedly attributed to the large-scale formation of the sharp interfaces, which could be critical for the photogenerated charge carrier separation and its transfer from the PTO phase to TiO2. It is suggested that the obtained heterostructured nanofiber composites TiO2/PbTiO3 can be exploited as an alternative visible-light-driven photocatalyst.

Pre-perovskite nanofiber: a new direct-band gap semiconductor with green and near infrared photoluminescence

Perovskite-related oxides exhibiting fascinating electric and magnetic properties are important functional materials. We report, for the first time, that pre-perovskite (PP) PbTiO3, characterized by one-dimensional (1D) TiO6 octahedron columns, has a direct-band structure with a gap of 3.20 eV. The faceted single-crystal nanofibers of PP-PbTiO3 demonstrate strong green and near infrared (NIR) photoluminescence (PL) emission at room temperature, which are intrinsic and subjected to quasi-1D crystal structure and electronic band structure. These nanofibers serving as new direct band-gap semiconductors may find applications in novel optical and optoelectronic devices.

Hydrothermal synthesis of ferroelectric PbTiO3 nanoparticles with dominant {001} facets by titanate nanostructure

A facile hydrothermal method has been developed to synthesize single-crystal ferroelectric PT nanoplates by using K2Ti6O13 nanowires as synthetic precursor. The PT nanoplates with dominant {001} facets have the side length of 500–700 nm and height of 100–150 nm. Piezoelectric force microscopy (PFM) results demonstrated that the PT nanoplates show obvious piezoelectric and ferroelectric activity. Moreover, the crystal growth of the PT nanoplates has been discussed. The results revealed that the gradual dissolution of K2Ti6O13 nanowires in alkali solution and the template of lead oxide are essential to the formation of PT nanoplates.

Investigation on CO catalytic oxidation reaction kinetics of faceted perovskite nanostructures loaded with Pt

Perovskite lead titanate nanostructures with specific {111}, {100} and {001} facets exposed, have been employed as supports to investigate the crystal facet effect on the growth and CO catalytic activity of Pt nanoparticles. The size, distribution and surface chemical states of Pt on the perovskite supports have been significantly modified, leading to a tailored conversion temperature and catalytic kinetics towards CO catalytic oxidation.

Li+ ion induced three-dimensional aggregation growth of single-crystal perovskite octahedrons

Li+ ions were introduced into a hydrothermal system as surfactants to tailor the growth of perovskite tetragonal PbTiO3 (PT) nanocrystals, giving rise to single-crystal octahedrons with {111} facets exposed. Systematic investigations reveal that single-crystal PT octahedrons were formed via a three-dimensional (3D) aggregation growth process. In the initial stage, the intermediate phase primary nanoparticles, with a size of 2–5 nm, aggregated to form an octahedral shaped particle agglomeration with a size of 20–50 nm; then, the particle crystallized via an oriented attachment (OA) mechanism, resulting in the observed single-crystal PT octahedrons. During this process, the interplay of Li+ ions and the electrostatic force of the primary nanoparticles are essential for octahedral aggregation and subsequent crystallization. Moreover, the concentration of Li+ ions has been demonstrated to significantly modify the growth of PT, leading to nanostructures with various shapes from hexahedral particles to cubic conglomerates to cuboids. These nanostructures demonstrate shape-dependent visible light photocatalytic activity.