Bifunctional Pd-O_x Center at the Liquid–Solid–Gas Triphase Interface for H₂O₂ Photosynthesis

Abstract

The coupling of H 2 O and O 2 by solar energy is regarded as the Holy Grail reaction for a manufacturing route of H 2 O 2 ; however, its efficiency has suffered from low O 2 solubility in aqueous solution and difficult-to-inhibit side reactions. Herein, a liquid−solid−gas triphase system has been designed to directly utilize abundant atmospheric O 2 for H 2 O 2 photosynthesis, the most important of which is the superhydrophobic photocatalyst of amino-containing ligands combined with Pd, loaded on BiVO 4 (Pd/A/BiVO 4 ). This relatively separated catalyst and product system successfully avoids the decomposition of produced H 2 O 2 and contributes to the accumulation of a high-concentration H 2 O 2 solution. The enrichment of O 2 and the kinetics of carriers and reaction intermediates are tunable via the interaction between Pd and amino groups, which promotes the photosynthetic yield of H 2 O 2 to 805.9 μmol g −1 h −1 in pure water under visible illumination. During the reaction, O 2 is not only converted into H 2 O 2 as a reactant but also participates in the construction of Pd-O x sites as a dynamic catalyst. Also, the Pd-O x intermediate is identified as a catalytic and photoelectronic dual center. This research opens up an intriguing avenue for designing the H 2 O 2 photosynthesis system.

Improved H2O2 photogeneration and stability on rational tailored polymeric carbon nitride via enhanced O2 adsorption

“…At present, there are many kinds of photocatalysts used in photocatalytic H 2 O 2 production. For example, TiO 2 , 12 BiVO 4 , 21 layered double hydroxides, 22 and polymeric carbon nitride (PCN). 15 O 2 + 2H + + 2e − → H 2 O 2 ; 0.68 V vs. NHEO 2 + H + + e − → ˙OOH; −0.33 V vs. NHE˙OOH + H + + e − → H 2 O 2 ; 1.05 V vs. NHE…”

Gas-phase photoelectrocatalytic oxidation of volatile organic compounds using defective WO3/TiO2 nanotubes mesh

“…It is noteworthy that reduction of O 2 to ˙O 2 − requires a quite high negative potential (−0.33 V vs. NHE), 47 and WO 3 , known as a low conduction band (CB) material, is inefficient at driving the reaction. Thus, O 2 should be reduced by the CB electron of the TiO 2 components in R-WO 3 /TNTs, following the Z-scheme mechanism of a WO 3 /TiO 2 heterojunction that had already been extensively reported.…”

Conjugated Organic Polymers with Anthraquinone Redox Centers for Efficient Photocatalytic Hydrogen Peroxide Production from Water and Oxygen under Visible Light Irradiation without Any Additives

“…Hydrogen peroxide (H 2 O 2 ) is a versatile chemical reagent that has been widely employed in wastewater treatment, the paper industry, organic synthesis, disinfection, and electronic industries because it only produces water and oxygen as by-products. − Meanwhile, H 2 O 2 is also a promising energy carrier with high energy density, which can serve as an alternative to hydrogen as it dissolves in H 2 O and could be used to generate electricity in a single compartment fuel cell. − These advantages result in a huge demand for and consumption of H 2 O 2 (predicted to be 6.0 million tons by 2023) . However, H 2 O 2 production still mainly depends on the anthraquinone method, which involves a complicated synthetic process, substantial energy consumption, and significant environmental contamination. − In addition, the use of precious metal catalysts and high-pressure H 2 in the stage of hydrogenation reaction not only increases the cost of the H 2 O 2 preparation process but also introduces many safety issues. , Thus, it is of great importance to develop alternative methods that are efficient, low-cost, and eco-friendly for H 2 O 2 production.…”

“…11−13 In addition, the use of precious metal catalysts and high-pressure H 2 in the stage of hydrogenation reaction not only increases the cost of the H 2 O 2 preparation process but also introduces many safety issues. 14,15 Thus, it is of great importance to develop alternative methods that are efficient, low-cost, and ecofriendly for H 2 O 2 production.…”