Designed Synthesis of Cu₂O Quantum Dots/TiO₂ Nanotubes Heterostructure as a Photocatalyst for Converting CO₂ to CH₄

Abstract

In this work, H+ in oxalic acid was used instead of Na+ to obtain titanate nanosheets through P200 hydrolysis, which further curled to form a multilayer TiO2 nanotubes (NTs) structure. Then, Cu2O quantum dots (QDs) were successfully loaded on TiO2 NTs by hydrothermal method using fructose as a reducing agent. The optical, impedance, and photocurrent tests indicated that the composite structure improved its optoelectronic performance. The photocatalytic H2 production and CO2 reduction efficiency of Cu2O QDs/TiO2 NTs were lower than those of TiO2 NTs. However, the molar ratio of CH4 to CO produced by CO2 reduction of Cu2O QDs/TiO2 NTs composite catalyst was greater than that of pure TiO2 NTs. The CH4 production accounted for 97%, indicating that the composite catalyst had a high CH4 selectivity. The experimental and DFT calculation results proved that the Z‐scheme heterojunction accelerated the separation and transfer of photo‐generated carriers, and broadened the absorption range of visible light.This article is protected by copyright. All rights reserved.