Electrochemical Synthesis Of Photoelectrocatalytic Thin Films Of Hexagonal BiPO₄ Nanorods And Bi/BiPO₄

Our principal aim is to synthesis BiPO₄, an oxy-acid salt catalyst, and Bi/BiPO₄ composite with stability and high activity on the FTO substrate via cathodic electrodeposition. We research the structure and particle size of BiPO₄ and introduced Bi to decrease the band edge of BiPO₄ catalyst. XRD、FESEM、HRTEM、Raman、XPS and DRS were used to characterize the structure and morphology of the products, and the photoelectrochemical properties of the films were measured by using EC-Lab. Photoelectrocatalytic degradation of Methylene Blue（MB） at BiPO₄ film electrode under UV light irradiation was also investigated. This work may provide further understanding for an oxy-acid salt catalysts. The main results are as follows:Hexagonal BiPO₄ nanorods thin films with remarkable photoelectrocatalytic（PEC） performance were firstly successfully fabricated on FTO substrates via cathodic electrodeposition. Chronoamperometry, linear sweep voltammertry（LSV） and electrochemical impedance spectroscopy（EIS） were used to study the photoelectrochemical properties of these materials. The photoelectrocatalytic capability was evaluated by the degradation of methyl blue（MB）. The film deposited in 40 min has the best catalytic activity and good stability with the 30 h degrading experiment. The photocurrent was increasing because the concentration of MB was being degrading. The CV analysis which reveals a potential shift and the increasing anodic and cathodic peak currents with increasing scan rate proves a diffusion-controlled process. The hydroxyl radicals are the main active species that can oxidize the adsorbed organic pollutants. Mott–Schottky（MS） measurements match the typical for n-type semiconductors.A facile one step electrochemical approach has been developed to prepare BiPO₄ photoelectrode with Bi nanoparticles on FTO substrates by adjusting the concentration of the H2O2 solution via cathodic electrodeposition. The Bi/BiPO₄ nanofilms have a compact structure with rod-shaped nanosized BiPO₄ crystals and irregular bismuth particles. The photocurrent on modified photoelectrode is significantly 10 times higher than on non-modified Bi PO4 photoelectrode. 50 times cyclic voltammetry（CV） show excellent long-term photostability. The changing of photoluminescence（PL） verifies the as-prepared composite photoelectrode decrease recombination of photoinduced electron-hole pairs. Doping of Bi nanoparticles in BiPO₄ nanostructures leads to a red shift of the absorption edge. The nanofilm photoelectrodes are believed to be potentially useful for practical applications and for fundamental electrochemical studies.