Characterization of raw materials and self‐organized Bi₂O₃–Ag eutectic by X‐ray diffraction, scanning electron microscopy, and X‐ray photoelectron spectroscopy

Abstract

Bi2O3–Ag raw materials were prepared using different synthetic routes: mortar and pestle and ball‐milling. They were later used as starting materials for the micro‐pulling down method. After the micro‐pulling down, the Bi2O3–Ag composites were annealed under vacuum, H2 and air atmospheres. All samples were characterized by the following methods: X‐ray diffraction (XRD), scanning electron microscopy (SEM/EDX) and X‐ray photoelectron spectroscopy (XPS). The SEM/EDS and XPS analyses showed that the raw materials prepared by ball‐milling had a much more homogenous distribution of silver. XPS investigations of all Bi2O3–Ag composites showed that Bi ions are mainly in the 3+ oxidation state but additionally some may exist in the Bi0 (metallic) and defected Bi(3‐x)+ valence states. In the case of Bi2O3–Ag composites grown from ball‐milled raw materials and annealed in H2, XPS studies clearly showed the presence of metallic silver nanoparticles, Ag0. Besides the nanoparticles, bulk metallic silver Ag0 and two oxidation states for silver Ag2O and AgO for all examined eutectic were found. The estimated band gap, based on XPS was about 2.8 eV. In the case of samples obtained from ball‐milled raw materials, additional states near the Fermi level were found which could be related to partial transformation of Bi2O3 into Bi0.

Carbonized Polymer Dots/Bi/β-Bi2O3 for Efficient Photosynthesis of H2O2 via Redox Dual Pathways

“…In β-Bi 2 O 3 , the peaks at 159.4 and 164.8 eV are attributed to Bi 4f 7/2 and Bi 4f 5/2 of Bi 3+ , respectively. 32 For CBO-1905, the Bi 3+ peaks shift toward the low binding energy and two new Bi 0 peaks (157.3 and 162.9 eV) emerge. 32 This again confirmed that Bi 3+ in CBO-1905 was reduced by EG to produce Bi.…”

“…32 For CBO-1905, the Bi 3+ peaks shift toward the low binding energy and two new Bi 0 peaks (157.3 and 162.9 eV) emerge. 32 This again confirmed that Bi 3+ in CBO-1905 was reduced by EG to produce Bi. In Bi 2 O 2 CO 3 , the peaks at 164.2 and 158.8 eV are attributed to Bi 4f 5/2 and Bi 4f 7/2 of Bi 3+ , respectively.…”

“…The high-resolution XPS spectra of Bi 4f are shown in Figure d. In β-Bi 2 O 3 , the peaks at 159.4 and 164.8 eV are attributed to Bi 4f 7/2 and Bi 4f 5/2 of Bi 3+ , respectively . For CBO-1905, the Bi 3+ peaks shift toward the low binding energy and two new Bi 0 peaks (157.3 and 162.9 eV) emerge .…”

Structural Color Generation on Transparent and Flexible Substrates by Nanosecond Laser Induced Periodic Surface Structures

“…Besides, the measurement of the doublet peak for the high scan XPS Ag 3d spectrum (Figure 2f) at 373.42 eV (Ag 3d 3/2 ) and 367.43 eV (Ag 3d 3/2 ) are due to the spin‐orbit coupling and could be assigned to the Ag(O‐R) 2 . [ 32 ] Additionally, a marginal chemical shift from the combined XPS data of Ti 2p and Ag 3d suggests that a part of Ag content is chemically bonded with Ti content. The high‐resolution of O 1s XPS spectrum (Figure 2f) includes four broad peaks measured at the B.E of 532.03, 531.57, 530.81, and 530.36 eV that can be assigned to the existence of adsorbed ‐OH/H 2 O, ‐O‐Ti, ‐OR‐Ag, and ‐OR‐Ti, respectively.…”

Visible Light-Driven Photoelectrocatalytic Water Splitting Using Z-Scheme Ag-Decorated MoS2/RGO/NiWO4 Heterostructure

“…The BE values of Mo 3d and S 2p are in close agreement with the previously published values. , Similar to Mo 3d and S 2p, the Ag 3d XPS spectrum (Figure h) was fitted into two doublet peaks positioned at 366.8 and 372.8 eV, which can be, respectively, assigned to Ag 3d 5/2 and Ag 3d 3/2 of metallic Ag 0 . These BE values are positively shifted by 0.6 eV than the literature values of metallic silver NPs indicating the electron transfer from Ag NPs to MoS 2 NS and NiWO 4 NPs. Thus, the binding energy shifts provide clear evidence of the expected charge-carrier transfer pathway across the interface of MoS 2 /NiWO 4 and Ag-MRGON heterojunctions.…”