Razi University

   Abstract In the first part, a ternary metal sulfide was designed as a photocatalyst for the removal of pollutants. CoSX@Ag2S/CdS nanostructures were prepared using ZIF-67-derived for CoSX via a one-pot solvothermal method. It is noteworthy that the formation of the hollow structure occurred concurrently with the generation of bimetallic sulfide particles on the surface of CoSx particles. The synthetic conditions were optimized by controlling temperature, time, and ZIF-67 amount. The resulting structure showed high photoactivity and used for remediation of water pollutant. The photocatalyst was successfully degraded rhodamine B (RhB) with 96% degradation rate within 90 min. Additionally, Cr(VI) could efficiently reduced with 100% efficiency within 50 min in pH 5 under exposure to visible light (light-emitting diode, 100 W). The photocatalyst also demonstrated excellent activity in the remediation of a mixture of RhB and Cr(VI). Such photoactivity was attributed to the unique architecture of CoSX@Ag2S/CdS in generating n-n-n type-I hybrid Z-scheme, compared to single and double components. This also results in a synergistic effect between metal sulfides and hollow structure, which enhances the light absorption, surface area, and active sites. It is proposed that the photocatalytic mechanism relies on a combination of two Z-scheme and type-I mechanism.    In the second part, a hollow microspherical bimetallic metal-organic frameworks (MOF) formed in-situ in the presence of bismuth (Bi3+) and indium (In3+) cations, which serve as the main components of the MOF secondary building blocks. In contrast, monometallic MOFs, Bi-MOF and In-MOF, exhibited distinct morphologies, with spherical nanoparticles and microrods, respectively. Morphological and structural characterizations revealed that hollow microspheres are composed of bismuth oxychloride (BiOCl)-like nanosheets. The InCl3 precursor provides chloride ions necessary for the formation of BiOCl. Various amounts of three-dimensional Bi/In-MOF were hybridized with two-dimensional Ti3C2 MXene to produce Bi/In-MOF/Ti3C2 composites via a solvothermal process, which exhibited high performance in the photodegradation of rhodamine B (RhB). The addition of 10 wt.% Ti3C2 and varying amounts of Bi/In-MOFs resulted in a narrower band gap (~2.6 eV) and a reduced charge recombination rate compared to the bimetal MOF alone (~3.18 eV), thereby enhancing photocatalytic efficiency under visible light. The Bi/In-MOF(20 wt.% In)/Ti3C2(10 wt.%) composite achieved a photocatalytic degradation efficiency of 95% for RhB under visible light irradiation (LED; 100 W) within 80 min. Scavenger test identified superoxide radicals (O2•?) and holes (h+) as the primary active species in RhB degradation. The photocatalyst demonstrated excellent structural stability, maintaining 87% degradation efficiency after four cycles of reuse.    In the third part, a NH2-MIL-125(Ti)/MIL-68(In) derived M-In2S3/TiO2 nanocomposites were synthesized by one-step solvothermal method. The precursor was prepared with different weight percentage from the NH2-MIL-125(Ti) (30, 50, and 70 wt.%). Moreover, the introduction of NH2-MIL-125(Ti)-30 enhanced the charge transfer separation, as seen from photocurrent, PL, and EIS analyses, which led to high photocatalytic performance. M-In2S3/M-TiO2-30 showed the highest photoreduction activity, achieving 98% in just 25 min under visible light irradiation (LED; 100 W), which is 6.45 and 12.9 times that of M-In2S3/M-TiO2-50 and M-In2S