Facile fabrication of binary g-C3N4/NH2-MIL-125(Ti) MOF nanocomposite with Z-scheme heterojunction for efficient photocatalytic H2 production and CO2 reduction under visible light
Riyadh Ramadhan Ikreedeegh, Sehar Tasleem, Md. Arif Hossen
Abstract
A binary g-C 3 N 4 /NH 2 -MIL-125(Ti) MOF nanocomposite was fabricated through a facile sonochemical-assisted thermal approach for enhanced photocatalytic H 2 production and CO 2 reduction under visible light. Compared to pure g-C 3 N 4 , the g-C 3 N 4 /MOF photocatalyst showed enhanced visible light absorption with promoted charge carrier separation which increased the H 2 production rate and the CO 2 reduction into CH 4 and CO. This enhancement was attributed to the successfully constructed Z-scheme heterojunction in addition to the visible-active, large surface area and highly CO 2 adsorbable NH 2 -MIL-125(Ti) MOF . The highest H 2 production of 480 µmol g −1 was exhibited over the g-C 3 N 4 /NH 2 -MIL-125(Ti) nanocomposite with 20 wt% MOF . Similarly, the highest CO production rate of 338 µmol g −1 was achieved with 20 wt% MOF composite. However, for the CH 4 product gas, it was observed that the highest production rate was attained with pure g-C 3 N 4 which reveals the NH 2 -MIL-125(Ti) MOF selectivity towards CO production instead of CH 4 . Among all the investigated sacrificial agents for H 2 production, methanol was the best. The performance of CO 2 reduction process was found to be increasing with the pressure increase. Furthermore, the stability investigations revealed continuous productions of H 2 , CO and CH 4 over the C 3 N 4 /MOF photocatalyst in multiple cyclic runs without any significant photocatalyst deactivation. This study provides new ideas for the fabrication of cheap, efficient and easy-synthesized nanomaterials for energy production and environmental remediation applications.