Bingan Lu

A facile method to prepare SnO2 nanotubes for use in efficient SnO2–TiO2 core–shell dye-sensitized solar cells

A high-efficiency photoelectrode for dye-sensitized solar cells (DSSCs) should combine the advantageous features of fast electron transport, slow interfacial electron recombination and large specific surface area. However, these three requirements usually cannot be achieved simultaneously in the present state-of-the-art research. Here we report a simple procedure to combine the three conflicting requirements by using porous SnO(2) nanotube-TiO(2) (SnO(2) NT-TiO(2)) core-shell structured photoanodes for DSSCs. The SnO(2) nanotubes are prepared by electrospinning of polyvinyl pyrrolidone (PVP)/tin dichloride dihydrate (SnCl(2)·2H(2)O) solution followed by direct sintering of the as-spun nanofibers. A possible evolution mechanism is proposed. The power conversion efficiency (PCE) value of the SnO(2) NT-TiO(2) core-shell structured DSSCs (∼5.11%) is above five times higher than that of SnO(2) nanotube (SnO(2) NT) DSSCs (∼0.99%). This PCE value is also higher than that of TiO(2) nanoparticles (P25) DSSCs (∼4.82%), even though the amount of dye molecules adsorbed to the SnO(2) NT-TiO(2) photoanode is less than half of that in the P25 film. This simple procedure provides a new approach to achieve the three conflicting requirements simultaneously, which has been demonstrated as a promising strategy to obtain high-efficiency DSSCs.

High‐Performance Photoelectrochemical‐Type Self‐Powered UV Photodetector Using Epitaxial TiO2/SnO2 Branched Heterojunction Nanostructure

TiO₂/SnO₂ branched heterojunction nanostructure with TiO₂ branches on electrospun SnO2 nanofiber (B-SnO₂ NF) networks serves as a model architecture for efficient self-powered UV photodetector based on a photoelectrochemical cell (PECC). The nanostructure simultaneously offers a low degree of charge recombination and a direct pathway for electron transport. Without correcting 64.5% loss of incident photons through light absorption and scattering by the F-doped tin oxide (FTO) glass, the incident power conversion efficiency reaches 14.7% at 330 nm, more than twice as large as the nanocrystalline TiO₂ (TiO₂ NC, 6.4%)-film based PECC. By connecting a PECC to an ammeter, the intensity of UV light is quantified using the output short-circuit photocurrent density (J(sc)) without a power source. Under UV irradiation, the self-powered UV photodetector exhibits a high responsivity of 0.6 A/W, a high on/off ratio of 4550, a rise time of 0.03 s and a decay time of 0.01 s for J(sc) signal. The excellent performance of the B-SnO₂ NF-based PECC type self-powered photodetector will enable significant advancements for next-generation photodetection and photosensing applications.

Reactive Oxygen-Doped 3D Interdigital Carbonaceous Materials for Li and Na Ion Batteries.

Carbonaceous materials as anodes usually exhibit low capacity for lithium ion batteries (LIBs) and sodium ion batteries (SIBs). Oxygen-doped carbonaceous materials have the potential of high capacity and super rate performance. However, up to now, the reported oxygen-doped carbonaceous materials usually exhibit inferior electrochemical performance. To overcome this problem, a high reactive oxygen-doped 3D interdigital porous carbonaceous material is designed and synthesized through epitaxial growth method and used as anodes for LIBs and SIBs. It delivers high reversible capacity, super rate performance, and long cycling stability (473 mA h g(-1) after 500 cycles for LIBs and 223 mA h g(-1) after 1200 cycles for SIBs, respectively, at the current density of 1000 mA g(-1) ), with a capacity decay of 0.0214% per cycle for LIBs and 0.0155% per cycle for SIBs. The results demonstrate that constructing 3D interdigital porous structure with reactive oxygen functional groups can significantly enhance the electrochemical performance of oxygen-doped carbonaceous material.

Graphene and graphene oxide double decorated SnO2 nanofibers with enhanced humidity sensing performance

We demonstrate humidity sensing with SnO2@G–GO nanocomposites using three important parameters for a sensing device: sensitivity, response and recovery time, and stability. Here, the SnO2@G–GO nanocomposites were fabricated by classical electrospinning and solution evaporation. The as-prepared SnO2@G–GO sensor demonstrated very high sensitivity (up to 32 MΩ/% RH), fast response and recovery time (less than 1 s), and good stability. Pure SnO2 and SnO2@G hybrid NFs were prepared as reference materials for humidity sensing. And they showed low sensitivity and slow response to humid air. The performance for the incorporation of graphene and graphene oxide with SnO2 to greatly improve the humidity sensing properties were discussed in detail.

Electrospinning-thermal treatment synthesis: a general strategy to decorate highly porous nanotubes on both internal and external side-walls with metal oxide/noble metal nanoparticles.

The hybrid structure of nanoparticle-decorated highly porous nanotubes combines the advantages of large specific surface areas of nanoparticles and anisotropic properties of highly porous nanotubes, which is desirable for many applications, including batteries, photoelectrochemical water splitting, and catalysis. Here, we report a novel emulsion electrospinning-thermal treatment method to synthesize the nanoparticles deposited on both side walls of nanotubes with two unique characteristics: (1) large loading amount of nanoparticles per highly porous nanotubes (with the morphology of nanoparticles); (2) intimate contact between nanoparticles and highly porous nanotubes. Both features are advantageous for the above applications that involve both surface reactions and charge transportation processes. Moreover, the emulsion electrospinning-thermal treatment method is simple and straightforward, with which we have successfully decorated various highly porous metal oxide nanotubes with metal oxide or noble metal nanoparticles. The new method will have an impact on diverse technologies such as lithium ion batteries, catalysts, and photoelectrochemical devices.

Core–shell ZnCo2O4@TiO2 nanowall arrays as anodes for lithium ion batteries

In this paper ZnCo2O4 nanowall arrays (NWAs) were first obtained through self-assembly followed by calcination. Then atomic layer deposition was used to fabricate core-shell ZnCo2O4@TiO2 NWAs as anode materials for lithium ion batteries (LIBs). The hierarchical NWA nanostructure has fast ion diffusion and electron transport at the electrode/electrolyte interface, while the excellent chemical stability of the TiO2 shell can protect the ZnCo2O4 NWAs from volume expansion during the charge and discharge processes. The core-shell ZnCo2O4@TiO2 core-shell NWAs composite is versatilexa0as an anode material and exhibits enhanced electrochemical performance for LIBs. The initial capacity was 1598 mA h g-1 (Coulombic efficiency reached 84.0%), and the reversible capacity after 90 cycles was 827 mA h g-1 at a current density of 100 mA g-1, showing high capacity and good cycling stability (much better than ZnCo2O4 NWAs). The ZnCo2O4@TiO2 nanocomposite also showed excellent rate capability with a reversible capacity of 532 mA h g-1 even at a current rate of 4500 mA g-1. The encouraging experimental results suggest that the novel core-shell structure NWAs have great potential for practical applications in LIBs.