Fig. 4
From: Recovery of platinum(0) through the reduction of platinum ions by hydrogenase-displaying yeast
XPS spectra of black precipitates. The black precipitates produced after the reduction were analyzed by X-ray photoelectron spectroscopy (XPS). Ni-Hyd, black precipitates produced by Ni-Hyd-displaying yeast (red line); Hyn B, black precipitates produced by Hyn B-displaying yeast (blue line); Control, precipitates produced by control yeast (green line). Binding energies of 70.7–71.3 eV (orange), 72.6–72.8 eV (pink), and 72.4–74.6 eV (light blue) correspond to Pt(0), Pt(OH)2, and PtO, respectively