Doping of silver vanadate and silver tungstate nanoparticles for enhancement the photocatalytic activity of MIL-125-NH2 in dye degradation

Recently, the increment in environmental pollution has challenged the investigation of photocatalytic systems. However, metal organic framework MOFs have superior photocatalytic action, it exhibits low efficiency of light energy because of their large effective band gap. Hence, the current study presents an innovative strategy for enhancing the photocatalytic activity of Ti-containing MOF (MIL-125-NH2) by doping of silver vanadate (Ag3VO4) and silver tungstate (Ag2WO4) nanoparticles. For the prepared composites, spherical nanoparticles of Ag3VO4 and Ag2WO4 were deposited on size regulated microcrystals of MIL-125-NH2. After doping of Ag2WO4 and Ag3VO4, the optical band gap of MIL-125-NH2 was decreased from 2.65 eV to 2.56 eV and 2.27 eV, respectively. The effect of doped nanoparticles on the photocatalysis of MIL-125-NH2 was monitored in the degradation reaction of Methylene Blue (MB) and Rhodamine B (RhB) dyes under UV and Visible light. The degradation of dyes (MB & RhB) was significantly enhanced by doping of nanoparticles. The rate of dye degradation (k(1)) was accelerated by factor of 1.6-2.1 and 2.1-4.9 due to doping of Ag2WO4 and Ag3VO4, respectively. Ag3VO4@MIL-125-NH2 exhibited the highest photocatalytic activity logically due to the lowest band gap. The efficiency of Ag3VO4@MIL-125-NH2 as photocatalyst was reduced by only 25.9-31 % after 5 regeneration cycles. The prepared composites are promising to apply as recyclable photocatalysts in the degradation of dyes in the sunlight, able to reuse for many cycles with substantial degradation efficiency.