“…According to the literature, the Au 4f 7/2 peaks appearing at the binding energies of 84.0 eV, 85.0 eV, and 87.0 eV (� 0.2 eV) can be attributed to Au 0 , Au + , and Au 3 + , respectively. [3,12,38] The relative contents and binding energies of Au species obtained from XPS are listed in Table 2. For the fresh Au/ ROX0.8(AQ)À H 2 O samples, the relative contents of Au 3 + , Au + , and Au 0 were 39.0 %, 13.2 %, and 47.8 %, respectively.…”