Preparation Of Nanostructured Films By Electrospray Technique For Catalytic Properties

With the rapid development of modern society,the huge demand for energy has become one of the most important issues affecting human life.Providing clean,cheap energy is a major challenge.Global energy is expected to rise from 17 TW in 2010 to27 TW in 2040.Fossil fuels such as coal,oil and natural gas play an important role in providing energy.However,the emissions of CO₂ make us anxious.As a clean energy carrier,hydrogen has high energy density and no pollution.Electrochemical and photoelectrochemical decomposition of water is considered to be a potential method for storing sustainable,intermittent energy sources in the form of H₂?eg,wind and solar?.The water splitting reaction is generally divided into oxygen evolution reaction?OER?and hydrogen evolution reaction?HER?,both of which are critical to the overall efficiency of the water splitting.HER is a relatively simple reaction involving the transfer of two electrons.In contrast,OER is inherently more complex and the evolution of oxygen is slow because it involves a four-electron transfer process.By far the most effective peroxidation catalysts are ruthenium and osmium oxides with high current density and low overpotential.However,high prices and low abundance limit their commercial applications.Therefore,it is of great significant to develop high-efficiency catalysts with low cost and high electrochemical performance.In this paper,nanostructured films were prepared by electrospray deposition.The effects of different morphologies and catalytic properties were investigated by adjusting substrate temperature,film thickness and voltage.Nickel cobalt oxide with spinel structure was prepared by electrospray deposition on FTO substrate.In the traditional electrode process,adhesives were usually used to avoid the loss of electrochemical active substances.However,the conductive agent and the polymer binder will hinder the electron transfer between the electrode and the electrolyte interface and reduce the electrochemical activity and stability.Therefore,we prepared the nanostructured NiCo₂O₄ thin films directly on FTO by electrospray technique.We mainly discussed the influence of substrate temperature,film thickness and electric field on the performance of semiconductor.The samples of nano porous structure NiCo₂O₄ have high catalytic current density and good stability.Rutile titanium dioxide was prepared on the FTO substrate by hydrothermal method,and nanoparticles were deposited on the titanium dioxide nanowires by electrospray technique.One-dimensional TiO₂ nanowires have a large specific surface area and provide direct electron transport channels for electron migration.Without reducing agent and surfactant,nanoparticles with controllable size and deposition can be synthesized.By changing the substrate temperature and volume of the precursor,Pd/TiO₂ composite structures with different sizes and deposition yield were precisely controlled.The highest photocurrent density of the Pd/TiO₂ photoanode was 1.4 mA cm^-22 at 1.23 V vsRHE,which was approximately 5 times higher than the pristine TiO₂.The onset potential with a significant cathodic shiftwas about 80 mV.The results show that the enhancement of PEC performance can be attributed to the enhancement of schottky junction and the enhancement of photoelectron and hole separation between titanium dioxide and Pd NPs.In addition,the synergistic effect of Pd nanoparticles and TiO₂ further improves the photocatalytic effect.The strong interaction between surface plasmon resonance and light induced by plasma metal nanostructures has attracted extensive attention in the field of photovoltaic.Photochemical oxidation of titanium dioxide with gold nanoparticles modified photoactive electrode was studied.The light response range can be adjusted by controlling the amount of Au nanoparticle deposition.Compared with pure TiO₂,the photocatalytic activity of Au/TiO₂ electrode was significantly enhanced.In this paper,NiCo2O4,Pd/TiO2 and Au/TiO2 composite nanostructured thin films were prepared by electrospray technique,providing a new idea for the preparation of electrocatalysts and a new breakthrough in the application of dye sensitization and perovskite solar cell.