Photoelectrocatalytic Reduction Of CO₂into Chemicals

This paper focus on the photoelectrocatalytic reaction of carbon dioxide into carbonaceous compounds in the light of the high-efficiency photocatalyst/electro-catalyst in homemade photoelectrocatalytic reactor.The simplified process is as follows:(1) light crosses the quartz window and reaches the nanostructured film (photoanode) where photo-generated electron and hole pairs are generated and protons evolve,(2) protons pass through the Nation membrane, while electrons are collected and reach the cathode through an external wire, and (3) protons react with CO2in the presence of electrons on the Pt nanoparticles supported on RGO electrocatalyst to give gaseous and liquid fuels. This paper put up with the use of the catalytic combination of Pt-decorated titania nanotube and reduced graphene oxide to realize the CO2photoelectrocatalytic reduction.We examine the ability to fabricate nanotube arrays of different shape, pore size, length, and wall thickness by varying anodization parameters including anodization voltage, anodization time, bath temperature and electrolyte type. We concluded the optimal condition of50V voltage,180minutes’anodization time and annealed under450centigrade in the ethylene glycol electrolyte. Electric properties of three types of electrocatalyst (Pt-carbon black, Pt-carbon nanotube and Pt-decorated reduced graphene oxide) was compared from their performance in the CO2photoelectrocatalytic reduction. It was concluded that the product selectivity and efficiency was effected by many parameters such as reactant status, electrocatalyst type, Pt particles size, bias potential, mesh number of foamed nickel and pH of electrolyte. Specifically, liquid phase reaction in the cathodic side perfomed better than the gaseous phase for the reason of its high mass transfer rate; RGO represented the best catalytic result among these three types of catalyst for its high specific surface area and Pt particles dispersibility on it; The Pt particles size increases by the reduction time in the step of RGO preparation, which brings in the escalating the dispersibility of Pt particles and at the same time is limited by the capacity for catalyst loading when the mesh number of foamed nickel arrived at90; The bias potential of2V is selected as the optimal condition as for the biggest carbon atoms conversion number per volt; The increased pH of the cathodic electrolyte has a positive effect on the whole photoelectrocatalytic performance when pH is under8.8, because it will be limited by the stable charge carrier transfer rate and the more difficult CO2reduction due to the increasing pH of the electrolyte after8.8.