▎ 摘　　要

NOVELTY - A symmetrical bifunctional photocatalyst comprises a titania nanotube array substrate, a graphene layer which is electrodeposited on the surface of substrate, and narrow band gap semiconductor nanoparticles which are deposited on the graphene layer as a photosensitizer. USE - Symmetrical bifunctional photocatalyst used in dual-chamber photoreactor for photocatalytic reduction of carbon dioxide (all claimed). ADVANTAGE - The symmetrical bifunctional photocatalyst enhances the ability of photocatalytic reduction of carbon dioxide, reduces the occurrence of reverse reaction, by performing photocatalytic oxidation of water and carbon dioxide reduction reactions in a separate area, and improves the photocatalytic carbon dioxide reduction efficiency. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (i) dual-chamber photoreactor which comprises an anode reaction cell and cathode reaction cell arranged symmetrically, two connection ports which are provided between the cathode and anode reaction cells, a Nafion (RTM: sulfonated tetrafluoroethylene based fluoropolymer-copolymer proton exchange membrane) which is fixed in intermediate portion of one connection port, a substrate which is provided with symmetrical bifunctional photocatalyst, and fixed in intermediate portion of other connection port, an inlet and outlet which is provided in top portion of anode reaction cell and cathode reaction cell, and a light window which is arranged on the side wall of the anode reaction cell; and (ii) photocatalytic reduction of carbon dioxide which involves adding water or electrolyte solution to anode reaction cell and cathode reaction cell of dual chamber photoreactor, directly exposing light on substrate to anode reaction cell through window, passing high purity nitrogen, and carbon dioxide gas into anode reaction cell through the inlet port, adding electrolyte solution into cathode reaction cell, hydrothermally and photocatalytically oxidizing and reducing carbon dioxide, and venting gas-phase products from the reactor with the carrier gas.