Synthesis and design of spinel ZnAl2O4 nanowires with PtO nanoparticles decoration for enhanced induced visible light Hg(II) reduction

Spinel ZnAl2O4 nanowires with mesopores networks have been synthesized using Pluronic P-123 as a template-assisted sol-gel approach and then PtO nanoparticles (0.2-0.8%) were uniformly anchored on ZnAl2O4 nanowires for Hg(II) ions reduction under illumination by visible light. Transmission electron microscopes image indicated PtO NPs about 5 nm decorated ZnAl2O4 nanowires having length of 200 nm and diameter of 10 nm. The optimum photocatalyst was 0.6%PtO@ZnAl2O4 nanowires, whose photoreduction ability of Hg(II) amounted to 100% within 30 min and its reaction rate constant was 0.054 min(-1), five times larger than that of bare ZnAl2O4 (0.011 min(-1)). The reduction ability over 0.6%PtO@ZnAl2O4 nanowires was enhanced 2.5 times larger than that bare ZnAl2O4. The photoreduction rate over 0.6%PtO@ZnAl2O4 nanowires was about 3.3 times greater than bare ZnAl2O4 nanowires. The formation of heterojunction can facilitate efficient charge separation and enhance the photoreduction performance, evidenced by the transient photocurrent and photoluminescence measurements. This work illustrated a simple and efficient route to design and form spinel PtO@ZnAl2O4 nanowires, which are anticipated to have practical applications in environmental technology under solar light.