A novel black TiO2/ZnO nanocone arrays heterojunction on carbon cloth for highly efficient photoelectrochemical performance

ZnO nanocone arrays (NCAs) decorated with black TiO2 nanoparticles (B-TiO2 NPs) were uniformly anchored on the surface of carbon cloth (CC) directly by a simply electrochemical deposition method. Thus a novel B-TiO2 NPs/ZnO NCAs-CC hierarchical heterostructure was formed. It displayed superior performance and achieved a higher photocurrent over 0.4 mA$cm-2 before the onset of the dark current, attributed to the separation of the photogenerated electron-hole pair. Based on the B-TiO2 NPs/ZnO NCAs-CC heterostructure, the catalyst was fabricated for promoting the separation of charge carriers. Moreover, the introduction of Ti3+ and oxygen vacancies on the surface of TiO2 NPs expanded the absorption band edge and enhanced the electrical conductivity as well as the charge transportation on the catalytic surface. It indicates that the B-TiO2 NPs/ZnO NCAs-CC composite is beneficial to the improvement of the photoelectrochemical (PEC) activity.