Synthesis and Characterization of cuprous selenide, cuprous oxide and cupric oxide and the Testing of Their Photocatalytic Ability in Various Media

Cuprous selenide crystals were synthesized and characterized using TEM and HRTEM analysis, absorption spectroscopy, and pXRD analysis. TEM analysis revealed hexagonal platelets 0.8--2.0 microm in size. UV-vis spectroscopy led to a direct band gap calculation of 1.71 eV and an indirect band gap of 1.15 eV. Crystallinity was confirmed via pXRD studies. Irradiation results showed that Cu2Se is capable of reducing water to H2 with an appropriate electron donor solution, though not catalytically. Cuprous oxide nanowires and cupric oxide nanobelts were synthesized and characterized using TEM analysis, absorption spectroscopy, and pXRD analysis. The cuprous oxide nanowires have diameters have 100 nm and lengths up to 4 microm. Diffuse reflectance spectroscopy led to a band gap calculation of 1.97 eV, and pXRD studies confirm crystallinity. The cupric oxide nanobelts are 400 nm wide and 1 microm long. UV-vis spectroscopy revealed a band gap of 1.88 eV, and crystallinity was confirmed using pXRD. Neither CuO nor Cu2O are active photocatalysts for water reduction.