Constructing 0D/1D Ag3PO4/TiO_(2) S-scheme heterojunction for efficient photodegradation and oxygen evolution

An S-scheme heterojunction photocatalyst is capable of boosting photogenerated carrier separation and transfer,thus maintaining high photooxidation and photoredox ability.Herein,a 0D Ag_(3)PO_(4) nanoparticles(NPs)/1D TiO_(2) nanofibers(NFs)S-scheme heterojunction with intimate interfacial contact was designed via the the hydro-thermal method.Benefiting from the abundant hydroxyl groups and size confinement effect of TiO_(2) NFs,the average diameter of the Ag_(3)PO_(4) nanoparticles decreased from 100 to 22 nm,which favored the construction of a 0D/1D geometry heterojunction.The multifunctional Ag_(3)PO_(4)/TiO_(2) sample exhibited excellent photocatalytic activity and stability in photocatalytic oxygen production(726μmol/g/h)and photocatalytic degradation of various organic contaminants such as rhodamine B(100%),phenol(60%)and tetracycline hydrochloride(100%).The significant improvements in the photocatalytic performance and stability can be attributed to the intimate interfacial contacts and rich active sites of 0D/1D geometry,fast charge carrier migration,and outstanding photoredox properties induced by the S-scheme charge-transfer route.This work offers a promising strategy for constructing 0D/1D S-scheme heterojunction photocatalysts for improved photocatalytic performance.

Electrospun Cu-doped In_(2)O_(3) hollow nanofibers with enhanced H2S gas sensing performance

One-dimensional nanofibers can be transformed into hollow structures with larger specific surface area, which contributes to the enhancement of gas adsorption. We firstly fabricated Cu-doped In_(2)O_(3) (Cu-In_(2)O_(3)) hollow nanofibers by electrospinning and calcination for detecting H2S. The experimental results show that the Cu doping concentration besides the operating temperature, gas concentration, and relative humidity can greatly affect the H2S sensing performance of the In_(2)O_(3)-based sensors. In particular, the responses of 6%Cu-In_(2)O_(3) hollow nanofibers are 350.7 and 4201.5 to 50 and 100 ppm H2S at 250 ℃, which are over 20 and 140 times higher than those of pristine In_(2)O_(3) hollow nanofibers, respectively. Moreover, the corresponding sensor exhibits excellent selectivity and good reproducibility towards H2S, and the response of 6%Cu-In_(2)O_(3) is still 1.5 to 1 ppm H2S. Finally, the gas sensing mechanism of Cu-In_(2)O_(3) hollow nanofibers is thoroughly discussed, along with the assistance of first-principles calculations. Both the formation of hollow structure and Cu doping contribute to provide more active sites, and meanwhile a little CuO can form p–n heterojunctions with In_(2)O_(3) and react with H2S, resulting in significant improvement of gas sensing performance. The Cu-In_(2)O_(3) hollow nanofibers can be tailored for practical application to selectively detect H2S at lower concentrations.

Preparation of FeCo-, FeNi- and NiCo-alloy coated cenosphere composites by heterogeneous precipitation

Precursors of binary alloy （Fe112C0112, Fel/2Ni1/2, Ni1/2Co1/2, hereinafter referred to as FeCo, FeNi, NiCo） coated cenospheres were prepared by heterogeneous precipitation under optimized conditions. Magnetic binary alloy coated cenosphere composites with core-shell structure were subsequently obtained by thermal reduction of the as-prepared precursors at 700℃ for 2 h under H2/N2 atmosphere. The results showed that the alloy coatings were uniform and the binary alloy coated cenosphere composites basically retained the spherical morphology, suggesting that the thickness of the alloy coating could be adjusted to fabricate core-shell composites with multilayer structures. The composites exhibited higher coercivity than the pure alloy powders, and could therefore be used for high-performance functional materials and devices.