Photocatalytic H2O‐to‐H2O2 and ‐H2 affected by Pd‐TiO2‐δ/TiO2. (30th August 2022)

• Record Type: Journal Article
• Authors: Wei, Ling‐Wei; Lin, Kuen‐Song; Wang, H. Paul
• Is Part Of: International journal of energy research. Volume 46:Number 15(2022)
• Page Start: 22690
• Page End: 22703
• Publication Date: 2022-08-30
• Subjects: EXAFS -- hydrogen -- hydrogen peroxide -- palladium -- photocatalysis -- titanium dioxide -- XANES; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Power resources -- Research -- Periodicals; 621.042
• DOI: 10.1002/er.8572
• Languages: English
• ISSNs: 0363-907X

Abstract

Summary: The 21st Conference of Parties suggested that a significant increase in solar‐driven electricity could assist in the practicable reduction of the continuously increasing global CO2 concentrations. Since the conversion efficiencies of TiO2 for photocatalytic H2 O‐to‐H2 O2 were relatively low (ie, 0.14 mmole H2 O2 /gTiO2 /min), the novel Pd‐TiO2‐δ /TiO2 photocatalysts for H2 O‐to‐H2 O2 and ‐H2 were, thus, prepared by dispersion of palladium (36‐86 ppm) on the Ti 3+ self‐doped TiO2 (Pd‐TiO2‐δ /TiO2 ). Specifically, a feasibility study for photocatalytic H2 O(l) ‐to‐H2 O2(aq) and ‐H2(g) affected by the Pd‐TiO2‐δ /TiO2 photocatalysts for green energy was carried out in the present work. Note that H2 O2 and H2 can be yielded through the photocatalytic two‐electron transfer reactions (O2 + 2H + + 2e − → 2H2 O2 and 2H + +2e − → H2 ) that are thermodynamically feasible. Palladium on TiO2 surfaces could effectively retard the recombination of photoexcited charges and facilitated the simultaneous formation of H2 O2 and H2 from H2 O. The photoactive Ti 4+ on the TiO2 surface could form peroxo‐species (Ti 4+ ‐O2 H − ) that further induced the formation of H2 O2 . In the presence of the Pd‐TiO2‐δ /TiO2 photocatalyst, under UV light irradiation for 90 min, very high yields of naturally separated H2 O2(aq) (0.45 mmole/gTiO2 /min) and H2(g) (0.16 mmole/gTiO2 /min) could be obtained simultaneously. A relatively high photo‐conversion efficiency (14%) for the Pd‐TiO2‐δ /TiO2 photocatalysts was achieved. This work demonstrates that using the unlimited solar energy, the effective Pd‐TiO2‐δ /TiO2 photocatalysts can enhance H2 O(l) ‐to‐H2 O2(aq) and ‐H2(g) for green energy. Abstract : Palladium on TiO2 surfaces could effectively retard the recombination of photo‐excited charges and facilitated the simultaneous formation of H2 O2 and H2 from H2 O. The photoactive Ti 4+ on the TiO2 surface could form peroxo‐species (Ti 4+ ‐OOH − ) that further induced the formation of H2 O2 . Under light irradiation for 90 min, very high yields of naturally separated H2 O2(aq) (0.45 mmole/gTiO2 /min) and H2(g) (0.16 mmole/gTiO2 /min) could be obtained simultaneously.