Photocatalytic splitting of H2O-to-H2O2 by BiOI/g-C3N4/CoP S-scheme heterojunctions. (23rd December 2022)

• Record Type: Journal Article
• Authors: Liou, Yu-Fang; Wei, Ling-Wei; Chen, Chiaying; Liu, Shou-Heng; Pu, Ying-Chih; Wang, H. Paul
• Is Part Of: New journal of chemistry. Volume 47:Number 4(2023)
• Page Start: 1825
• Page End: 1831
• Publication Date: 2022-12-23
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/d2nj04216a
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : New BiOI/g-C3 N4 /CoP S-scheme heterojunction has a high efficiency for the reversible photocatalytic H2 O-to-H2 O2 reaction, which shows its suitability for applications in H2 O2 -fuel cells to generate electricity using solar energy. Abstract : Photocatalytic H2 O-to-H2(g) and –H2 O2(aq) (2H2 O(l) → H2(g) + H2 O2(aq) ) by a two-electron reaction is kinetically feasible. The proton-coupled two-electron transfer induced a photocatalytic oxygen reduction reaction (ORR) from oxygen and water is also an accessible path for the safe production of H2 O2 . It is thus desirable to synthesize effective photocatalysts that yield H2 O2 by the coupling of two-electron transfer water oxidation (+1.23 VNHE ) and ORR (+0.68 VNHE ). In this work, new g-C3 N4 /BiOI S-scheme heterojunctions with co-catalyst cobalt phosphide (CoP) (BiOI/g-C3 N4 /CoP) were prepared for the photocatalytic H2 O-to-H2 O2 reactions. The BiOI/g-C3 N4 /CoP heterojunctions can enhance visible light absorption and reduce electron–hole pair recombination rates. Because of the water splitting by two-electrons and reduction of oxygen, the BiOI/g-C3 N4 /CoP heterojunctions have a better photocatalytic H2 O-to-H2 O2 yield than with the BiOI/g-C3 N4 heterojunction by 3.0–8.4 times. With more CoP ( i.e., 19 wt%) on the BiOI/g-C3 N4, the BiOI/g-C3 N4 /(CoP)0.19 heterojunction generates more photocatalytic H2 O2 with higher formation rate constant ( k f ), equilbrium constant ( K ), and a lower decomposition rate constant ( k d ). This new, low-cost and ready-prepared BiOI/g-C3 N4 /CoP S-scheme heterojunction has a high efficiency for the reversible photocatalytic H2 O-to-H2 O2 reaction, which could be feasibly used for applications in H2 O2 -fuel cells for electricity using solar energy.