Herein, we constructed an ordered nanoporous embedding nanoparticles composite by anodic oxidation of Ti 3 SiC 2 in fluorine containing organic electrolyte. Compared to anodized Ti which resulted in TiO 2 nanotubes , the anodized Ti 3 SiC 2 (ATSC) led to the formation of nanostructured TiO 2 /C/SiO 2 composite. The morphologies of oxides in the composite also varied with different anodization parameters. The ATSC could be directly used as an electrode without further processes, which possessed a superior structure and composition with a visible-light photocurrent density of 7.56 μA cm −2 , initial reversible area capacity of 6.18 F cm −2 , which were respectively 1.32 and 6.87 times higher than those of the anodized Ti (AT), respectively. The ATSC synthesized by such a feasible fabricating strategy shows favorable photoelectrochemical properties and remarkable stability, and may broaden the bifunctional material prospects of anodized MAX phases.
Photoactive WO 3 is attractive as a photocatalyst for green energy evolution through water splitting. In the present work, an electrochemical anodic oxidation method was used to fabricate a photo-responsive nanotube array-like WO 3 /W (NA-WO 3 /W) photoanode from W foil as a precursor. Compared with a reference commercial WO 3 /W electrode, the NA-WO 3 /W photoanode exhibited enhanced and stable photoelectrocatalytic (PEC) activity for visible-light-driven water splitting with a typical H 2 /O 2 stoichiometric ratio of 2:1 and quantum efficiency of approximately 5.23% under visible-light irradiation from a light-emitting diode ( λ = 420 nm, 15 mW/cm 2 ). The greatly enhanced PEC performance of the NA-WO 3 /Wphotoanode was attributed to its fast electron–hole separation rate, which resulted from the one-dimensional nanotube array-like structure, high crystallinity of monoclinic WO 3 , and strong interaction between WO 3 and W foil. This work paves the way to a facile route to prepare highly active photoelectrodes for solar light transfer to chemical energy .
Jiajie Yu,Muzhong Shen,Siyu Liu,Feng Li,Dongping Sun,Tianhe Wang
In this paper, we describe a simple technique for direct growth of gold nanoparticles (GNPs) into a nanostructured porous alumina layer on conductive glass slide (PAOCG). PAOCG was attached firmly with a small piece of steel and was then immersed in a HAuCl 4 solution. Electro-induced electrons from steel were employed to reduce AuCl 4 − on PAOCG. The galvanic replacement reaction (GRR) was adopted as the fundamental mechanism for reducing metal precursors. This mechanism was further studied by open circuit potential-time (OCP-t) experiment and the result demonstrated that steel induced the continuous proceeding of this reaction. This strategy presents a simple and general protocol for preparation of metal nanoparticles (MNPs) on conductive glass substrates. The SERS properties of Au/PAOCG were investigated using aqueous crystal violet (CV) and 4-mercaptopyridine (4-Mpy) as probe molecules. Au/PAOCG allowed as low as 10 −9 M CV and 10 −8 M 4-Mpy to be detected. The reusability of this substrate was achieved by measuring the SERS spectrum of the probe molecules followed with a 400 °C heat treatment for 10 min to remove the residuals. This substrate could be reused for at least ten cycles without any significantly reduced SERS performance. Therefore, this surface can serve as a portable, durable and reusable SERS substrate and has a potential for commercial applications.