Z-scheme g-C3N4/C/S-g-C3N4 heterostructural nanotube with enhanced porous structure and visible light driven photocatalysis

Abstract

Z-scheme heterojunction photocatalysts often combine the merits of high charge separation efficiency and excellent redox capability. However, ternary g-C 3 N 4 based Z-scheme photocatalytic tandem systems can hardly possess these advantages owing to their low surface area and porosity. We herein report a mesoporous Z-scheme g-C 3 N 4 /C/S-g-C 3 N 4 heterostructural nanotube with a high surface area of 450 m 2 g −1 , synthesized by a nanocasting approach using a highly porous carbon nanorod (CNR) as both the sacrificial template and carbon source. Zinc-trimesic (Zn-BTC) metal organic framework-derived CNR was acidified (denoted as ACNR) before the anchorage of thiourea and dicyandiamide. And the resultant composite (ACNR@TU/DCDA) was subsequently pyrolyzed under mixed N 2 /air atmosphere, affording g-C 3 N 4 /C/S-g-C 3 N 4 heterostructural nanotube in situ . Due to the efficient charge-carrier separation, high redox capability and increased visible light absorption facilitated by the enhanced porous structure, the resultant g-C 3 N 4 /C/S-g-C 3 N 4 nanotube proves to be highly efficient for the degradation of methylene blue (MB), rhodamine-B (RhB) and congo red (CR). And the largest reaction factor of 2.37 min −1 g −1 is obtained towards the degradation of MB under visible light irradiation, that remarkably exceeds those over other g-C 3 N 4 based photocatalysts. The concept of in situ fabrication of high surface area g-C 3 N 4 /C/S-g-C 3 N 4 heterostructural nanotube revealed in this study will shed light on the synthesis of other ternary Z-scheme photocatalysts with enhanced porous structure and photocatalytic performance. Z-scheme g-C 3 N 4 /C/S-g-C 3 N 4 heterostructural nanotube with enhanced porous structure exhibits improved charge-carrier separation, high redox capability and increased visible light absorption, and is proved to be highly efficient for the degradation of methylene blue under visible light irradiation. • Zn-MOF-derived carbon nanorod as a highly porous template and a carbon source. • High surface area, ternary g-C 3 N 4 /C/S-g-C 3 N 4 Z-scheme nanotube photocatalyst. • Enhanced visible light absorption, charge-carrier separation and redox capability. • A largest reaction factor of 2.37 min −1 g −1 for the degradation of methylene blue.