Enhanced dark catalysis reduction of organic dyes and heavy-metal pollutants over activated carbon-supported V/S-BiOBr

Abstract

This paper explores how the strategic immobilization of vanadium and sulfur co-doped bismuth oxybromide (V/S-BiOBr) nanoparticles on to activated carbon (AC) scaffolds can be used to address the problem of nanoparticles aggregation and insufficient availability of active sites. The support of V/S-BiOBr was done via a systematic hydrothermal pathway on three different carbon scaffolds, microporous (1AC), mesoporous (2AC), and hierarchical micro–mesoporous (3AC). The specific surface area of the unsupported catalyst is 23 m2/g, and that of the 2AC composite is 420 m2/g) and supports the homogeneous distribution of active phases. Reductive degradation of methyl blue (MB), methyl orange (MO), and chromium (VI) of NaBH4 in the presence of synthesized composites under dark conditions were used to evaluate the catalytic efficacy of the obtained composites. The mesoporous V/S-BiOBr@2AC structure was the most successful tested material to meet the objective with a high percentage (>100) of all pollutants reducing in 10-12 min. This amplified activity is explained by the synergetic interaction of the AC support and V/S-BiOBr that promotes the high-rate of mass transfer, reduction of interfacial charge-transfer resistance, and optimization of electronic environment through oxygen vacancies and V5+/V4+ transformation. Moreover, the V/S-BiOBr@2AC catalyst was extremely stable in terms of structure and reuse as it did not change greatly after several cycles. These results show that the V/S-BiOBr@AC system is a strong and effective system to perform a high level of environmental recovery and treatment of wastewater.