【正文】 are these mon pollutants. Because of their high stability, high toxicity and a carcinogenic character, they may cause serious damage and threat to the aquatic life and human health. To remove these recalcitrant anic pollutants effectively is a great challenge for environment and energy scientists. One promising technology is heterogeneous photocatalysis, which has been regarded as holding the potential in utilizing solar energy to remove various anic pollutants. Titania is one of the most attractive functional materials with fascinating properties on diverse fields, and one practical application of titania is photocatalytic degradation of anic pollutants. It can be used to thorough mineralize pollutants with such advantages as low cost, high efficiency and stability. To avoid plicated separation from liquid, loading TiO2 is one crucial process for the photocatalysis technology applied in aqueous purification. Solgel dip coating with surfactant template additions is one of the general strategies to prepare mesoporous immobilized TiO2 films. However, it is not facile to obtain a large scale film via this approach, and the photocatalytic activity of the film is always not satisfactory for practical application. In situ synthesis of TiO2 film has been studied recently. Wu et al. developed the method of oxidation of Ti substrate using ? Corresponding author. Email: 11 / 40H2O2 solution (Wu J M, 2022). The nanorod film prepared by this method has good photocatalytic activity. But the oxidation time is too long (72 hours). Chi et al. report a direct synthesis of titanate nanotube film by hydrothermal treatment of Ti substrate in concentrated NaOH at relatively higher temperature (Chi B, 2022). However, the hydrothermal treatment is not suitable for economical large scale production. And titanates always exhibit lower photocatalytic activity due to their wide band gap and significant rebination. Herein, we reported a facile approach to synthesize porous anatase TiO2 nanowire thin films via low temperature oxidation of metallic Ti plates in concentrated H2O2 and NaOH mixed solution, followed with proton exchange and subsequent calcinations. 1 Materials and methods Sample preparationTi plates (% in purity, Shanghai, China) with sizes of 22 cm2 were sonicated in ethanol, and pickled in 5 wt% oxalic acid solution for 2 h at 100 oC, and then rinsed with deionized water and dried in an oven at 40 oC. Each piece of treated Ti plate was soaked in a mixed solution of 16 ml H2O2 (30 wt%) and 16 ml NaOH (10 M) in an Teflonlined stainless steel autoclave. The autoclave was maintained at 80 oC for different time. After the autoclave was cooled to room temperature, the Ti plate was rinsed gently with deionized water and dried to obtain the product denoted as Tt (t is the reaction time in H2O2 and NaOH solution). Then the as prepared Ti plate was protonized through twice cycles of ion exchange in 50 ml M HCl for 2 h each time, and subsequently taken out, rinsed to neutral with deionized water, dried at 80 oC, and finally calcined at 400 oC for 1 h. And the resulted products were obtained and designated as ATt. Sample characterizationSurface morphology was observed using field emission scanning electron microscopy (FESEM, FEI SIRION 200) with an energydispersive Xray spectrometer (EDX, INCA OXFORD) attached to the SEM. Before the SEM examination, the samples were sputtered with a golden layer to improve the electrical conductivity. The crystals of the films were analyzed using a powder Xray diffraction (XRD) measurements on a Rigaku D/max3B diffractometer with Cu Ka radiation, operated at 40 kV, 36 mA (λ= nm). The Raman spectra were obtained with a Raman microscope system (InVia Renishaw Raman, Renishaw) using an Arion laser at 20 mW ( nm) for excitation. The Ramanscattered light was collected, dispersed and detected by a CCD camera with a spectral resolution of about 6 cm1. Phenol degradationTwo pieces of as prepared Ti plate were applied on the degradation of 50 ml 20 mg/L phenol solution. A 1000 W xeno lamp was employed as the light source, and the incident light is about 120 cm above of the phenol solution, and the Ti plate is placed on a bracket, approximate 2 cm below the liquid surface. Whole homogeneous of solution was controlled by stirring. Samples were taken at regular time intervals. The concentration of phenol was monitored by modified colorimetry with a UNICO UV2102 spectrometer(Hong X T, 2022). A control test of phenol photodegradation was done over an original pickled Ti plate.2 Results and discussion12 / 40 Characterization of titania nanowire thin filmThe typical morphology of porous nanowire film formed is shown in figures 1(a)–(c). It was noted that small porous cavity formed after treatment for 1 h (), however, the nanowire was thin and porous work was not obvious. With increasing of treatment time, the cavity is enlarged and the diameter of the nanowires widened. The porous work fully developed after 6 h reaction (). FESEM morphology of the porous titanate nanowire film through the reaction of a Ti plate in a H2O2 and NaOH solution at 80 176。C for different times (a: T1。 b: T3。 c: T6。 d: T12。 e: T24。 f: T48).The titanates nanowire was stable and kept the onedimension microstructure after calcined at 400 oC for 1 h (, designated as TC24). The EDX analysis showed that there is sodium present, as well as Ti and O (). However, it is well known that the photocatalytic activity of titanates was low due to their high band gaps (about eV) and significance rebinations of photogenerated charges. To obtain in situ titania nanowire film, the oxidized Ti plate was subsequently treated protonicly in HCl solution. And then the titanate nanowires were converted into the protonic forms. The EDX analysis shows the absence of sodium on th