Enhanced Photocatalytic Production of H₂O₂ through Regulation of Spatial Charge Transfer and Light Absorption over a MnIn₂S₄/WO₃ (Yb, Tm) Z-Scheme System

Abstract

The photocatalytic production of hydrogen peroxide (H 2 O 2 ) from H 2 O and O 2 is a promising approach, owing to its advantage of utilization of green solar energy without addition of organic sacrificial agents. However, the H 2 O 2 productivity is still far from satisfactory, due to inefficient sunlight absorption and the low photogenerated charge mobility of photocatalysts. Herein, a Z-scheme photocatalytic system is constructed by combining MnIn 2 S 4 with Yb 3+ and Tm 3+ WO 3 (WO 3 (Yb, Tm)) semiconductors. The Z-scheme interface heterojunction can inhibit the recombination of photogenerated carriers and retain photogenerated electrons and holes with high redox potentials. Particularly, the co-doped Yb 3+ and Tm 3+ can harvest near-infrared (NIR) excitation energy and then generate fluorescence emission with shorter wavelengths, which is beneficial to expand the optical response range of the photocatalytic system. With the synergy of the promoted photogenerated charge separation and enhanced optical absorption, the proposed photocatalytic system of MnIn 2 S 4 /WO 3 (Yb, Tm) exhibits a H 2 O 2 production rate of 1188 μmol h −1 g −1 in pure water, which is 37.2 and 8.8 times that of WO 3 and MnIn 2 S 4 , respectively. This work offers a new avenue for the design and improvement of photocatalytic systems for H 2 O 2 production.

Promising Materials for Photocatalysis‐Self‐Fenton System: Properties, Modifications, and Applications

“…In addition, except for the eminent abovementioned photocatalysts, some other catalysts still possess outstanding H 2 O 2 generation, which could be further investigated for the application to the PSFs and their potentials are displayed in Figure 16. [159][160][161][162][163][164][165][166][167]…”

Hydrogen Peroxide Production by Inorganic Photocatalysts Consisting of Gold Nanoparticle and Metal Oxide toward Oxygen Cycle Chemistry

“…76 A Z-scheme-type photocatalyst consisting of MnIn 2 S 4 /WO 3 co-doped with Yb and Tm has recently been reported for the H 2 O 2 photosynthesis. 77 The photocatalyst produced H 2 O 2 from water and O 2 with a rate of ∼600 μM h −1 under illumination of similated sunlight (AM 1.5, one sun). The high photocatalytic activity was ascribable to the synergy of the efficient light harvesting due to the near-infrared-to-visible upconversion by the Yb and Tm doping into WO 3 , and effective charge separation.…”

“…The development of all-solid-state Z-scheme-type photocatalysts is a fascinating approach to achieve efficient artificial photosynthesis . A Z-scheme-type photocatalyst consisting of MnIn 2 S 4 /WO 3 co-doped with Yb and Tm has recently been reported for the H 2 O 2 photosynthesis . The photocatalyst produced H 2 O 2 from water and O 2 with a rate of ∼600 μM h –1 under illumination of similated sunlight (AM 1.5, one sun).…”

Incorporating Ni-Polyoxometalate into the S-Scheme Heterojunction to Accelerate Charge Separation and Resist Photocorrosion for Promoting Photocatalytic Activity and Stability

“…To further verify the S-scheme mechanism of the CZS/Ni 4 POM heterojunction, the EPR spectra of superoxide (•O 2 – ) radicals of prepared photocatalysts were measured under light irradiation with 5,5-dimethylpyrroline N -oxide (DMPO) . As shown in Figure f, a typical DMPO-•O 2 – signal can be clearly observed over CZS and CZSNi-70, suggesting H 2 O 2 production can be achieved by ORR via the two-step single-electron route.…”