Abstract
This work presents the use of activated charcoal passivated-Ag<sub>3</sub>PO<sub>4</sub> (CAgP) and bare Ag<sub>3</sub>PO<sub>4</sub> (AgP) nanoparticles (NPs) as effective photocatalysts for the generation of hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) in air-saturated water containing either formic acid (FA) or silver nitrate (AgNO<sub>3</sub>). The synthesized CAgP and pristine AgP were characterized using various state-of-the-art optical and electron microscopy techniques. The CAgP composites showed remarkable photocatalyzed H<sub>2</sub>O<sub>2</sub> formation compared to bare AgP NPs. The CAgP photocatalyzed-assisted H<sub>2</sub>O<sub>2</sub> formation from O<sub>2</sub> -saturated water under sunlight was achieved via two-channel mechanisms. First, in the presence of FA as a hole scavenger, enhanced H<sub>2</sub>O<sub>2</sub> formation was facilitated by decomposition of FA to produce proton (H<sup>+</sup>), followed by a spontaneous reduction of dissolved molecular oxygen by the photo-excited electrons. The second photocatalytic pathway involves the formation of H<sub>2</sub>O<sub>2</sub> in the absence of electrons (using AgNO<sub>3</sub> as an electron scavenger) which occurred via oxidation of H<sub>2</sub>O by photo-induced holes to generate hydroxyl radicals ( ● HO) and the combination of photogenerated ● HO to produce H<sub>2</sub>O<sub>2</sub>. The most notable feature of CAgP composite as a photocatalyst is the ease of H<sub>2</sub>O<sub>2</sub> formation in O<sub>2</sub>/H<sub>2</sub>O and O<sub>2</sub>/H<sub>2</sub>O/FA system, as well as the ability to reuse the recovered CAgP catalyst for a few reaction cycles without losing substantial catalytic activity or mass.
Original language | English |
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Publisher | SSRN |
DOIs | |
Publication status | Published - 23 Apr 2022 |