Interaction of Single-Atom Platinum–Oxygen Vacancy Defects for the Boosted Photosplitting Water H₂ Evolution and CO₂ Photoreduction: Experimental and Theoretical Study

Abstract

The incorporation of oxygen vacancy defects into the catalysts has been attracting significant interest for regulating the performance of photocatalysts. Single-atomic-site metal catalysts have also been paid ever-growing attention because they maximized the atom efficiency and thus generated excellent catalytic performance. Herein, we report the interaction of oxygen vacancy defects and decorated atomically dispersed metal Pt to boost the efficient photocatalytic process. Compared with TiO2 without oxygen defects, under the same theoretical amount of Pt support, all the oxygen vacancy defect-rich TiO2 catalysts show excellent photocatalytic H2 generation and CO2 reduction performance. On the basis of the experimental characterization and quantum chemical calculations, the introduced oxygen vacancies strongly anchored the single-atom Pt on the surface of the catalyst with enhanced Pt-substrate interactions and thereby avoiding aggregation of Pt atoms, while the loaded single Pt atom favor the generation of more surface and subsurface oxygen vacancies as proved by electron spin resonance and positron annihilation lifetime spectroscopy. This work represents a new heuristic research of the coeffect of the defects and supported single noble metal atom and the rational synthesis of high-efficiency photocatalysts.

Insight into the Roles of Metal Loading on CO2 Photocatalytic Reduction Behaviors of TiO2

“…To confirm the key bond characteristics of adsorbed CO 2 anion, the vibration frequency calculations were obtained. Three key vibrational modes of CO 2 including symmetric (ν1), bending (ν2), and asymmetric (ν3) stretching modes were agreed to for other calculations for CO 2 anion adsorption on M 4 - TiO 2 surfaces [ 47 , 59 , 69 ].…”

Co‐doping of P(V) and Ti(III) in leaf‐architectured TiO2 for enhanced visible light harvesting and solar photocatalysis

“…This is in accord with previous results that incorporation of P(V) and oxygen vacancies considerably inhibited the recombination rate of photogenerated e − -h + pairs. 45,47 The results above showed that P(V) doping at a moderate level stabilized Ti(III) and oxygen vacancies at a high concentration, leading to an enhanced light harvesting, charge separation, and transfer (Figure 6 and Figure 7).…”

“…1,44 The secondary emission peak was present at 450-550 nm and should be due to transition at subband induced by dopants and oxygen vacancies. 45 The spinach-leafarchitectured TiO 2 showed a redshift of more than 50 nm in the secondary emission peak in comparison with P25. The redshift confirms that extra band levels were introduced by P(V) and Ti(III) dopants.…”

“…The smaller arc radius is normally related to the charge migration at the semiconductor-electrolyte interface. 45,46 M-P-TiO 2 shows the smallest radium of semicircles in the middle-frequency region, indicative of the highest charge transfer rate. Since there is only one semicircle, the EIS Nyquist plots can be fitted with Randles equivalent circuit model (inset in Figure 7B).…”

The Synergistic Effect of Heteroatom Doping and Vacancy on The Reduction of CO2 by Photocatalysts

“…He et al. used titanic acid nanotubes as the precursor to prepare OV‐rich TiO 2 , with the help of the density functional theory (DFT) calculations combined with experimental characterization, they had clearly understand the synergy mechanism between vacancy and Pt atom in the photocatalytic reaction process [44] . From the electron spin resonance spectra (ESR) (Figure 5), the intensity of ESR signal about Pt‐VO‐TiO 2 ‐500 is stronger than VO‐TiO 2 ‐500, Indicating that the oxygen vacancy concentration of Pt‐VO‐TiO 2 ‐500 is higher than VO‐TiO 2 ‐500.…”