Facial Construction of Hydroxyl Functional Modified Ultrafine BiPO₄ with Variation of Dipole Moment Induced by –OH Group

Abstract

The hydroxyl groups generated by hydrolysis are grafted onto the surface of BiPO4, and a stable surface hydroxylation structure is formed during the subsequent calcination process. This would facilitate the formation of a new hydroxyl functional structure on the surface of the parent photocatalyst without damaging its intrinsic structure. Synchronous illumination X‐Ray photoelectron spectroscopy shows that the hydroxyl functional ultrafine BiPO4 can realize the conversion of defective oxygen to lattice oxygen, which is more conducive in improving the photocatalytic efficiency. The process of filling hydroxyl oxygen vacancies and forming a stable structure is explored using in‐ situ infrared spectroscopy. The induced dipole moment promotes the separation of photogenerated electron–hole pairs, which is beneficial for the enhancement of photocatalytic activity. The dipole moment of the hydroxyl functional‐modified ultrafine BiPO4 is −1.409 D compared to −1.385 D for ordinary BiPO4. The results of this study indicate that hydroxyl functional structure and reduced sample granularity are effective strategies to improve the photocatalytic performance of BiPO4.

Tuning electronic levels in photoactive hydroxylated titania nanosystems: combining the ligand dipole effect and quantum confinement

“…We note that very recently reported experiments have indicated that the induced dipole effect of deliberately grafted –OH ligands can enhance of photocatalytic activity of BiPO 4 . 50…”

In Situ Analysis Photogenerated Electron Transport Behavior of C Self-Doped Carbon Nitride for Photocatalytic H2 Production

“…The O 1s XPS spectra also indicated that, upon visible light excitation, all three characteristic peaks shifted toward lower energy (as shown in Figure c). The observed shifts in binding energies suggest that photogenerated electrons transfer from the heptazine core to the surface structure …”

“…The observed shifts in binding energies suggest that photogenerated electrons transfer from the heptazine core to the surface structure. 30 Additionally, we conducted an analysis of the synchronous illumination XPS technique on HCN-EDA-Pt, which is loaded with the noble metal platinum (Pt), as shown in Figure 5d−f. The observed trends were found to be consistent with those of HCN-EDA, suggesting that the presence of Pt did not alter the pathway of photogenerated electron transfer.…”