Co(3)O(4)–Ag photocatalysts for the efficient degradation of methyl orange

In this paper, a series of Co(3)O(4)–Ag photocatalysts with different Ag loadings were synthesized by facile hydrothermal and in situ photoreduction methods and fully characterized by XRD, SEM, TEM, FTIR spectroscopy, XPS, UV-vis and PL techniques. The catalysts were used for the degradation of methyl orange (MO). Compared with the pure Co(3)O(4) catalyst, the Co(3)O(4)–Ag catalysts showed better activity; among these, the Co(3)O(4)–Ag-0.3 catalyst demonstrated the most efficient activity with 96.4% degradation efficiency after 30 h UV light irradiation and high degradation efficiency of 99.1% after 6 h visible light irradiation. According to the corresponding dynamics study under UV light irradiation, the photocatalytic efficiency of Co(3)O(4)–Ag-0.3 was 2.72 times higher than that of Co(3)O(4) under identical reaction conditions. The excellent photocatalytic activity of Co(3)O(4)–Ag can be attributed to the synergistic effect of strong absorption under UV and visible light, reduced photoelectron and hole recombination rate, and decreased band gap due to Ag doping. Additionally, a possible reaction mechanism over the Co(3)O(4)–Ag photocatalysts was proposed and explained.