Boosting hydrogen peroxide production of brookite TiO₂ with Au and MXene co-catalysis under UV light

Abstract

In this study, a new brookite TiO2/monolayer Ti3C2Tx MXene/Au composite was developed for photocatalytic synthesis of hydrogen peroxide (H2O2). The optimal ratios of MXene and Au were found to be...

Weakened Interfacial Hydrogen Bond Connectivity Drives Selective Photocatalytic Water Oxidation toward H2O2 at Water/Brookite-TiO2 Interface

“…4,15,16 This is particularly notable on the b-TiO 2 (210) surface, which has a high rate of OH • radicals, a key intermediate for H 2 O 2 generation. 7,17,18 This selectivity has not been observed on the extensively studied r-TiO 2 (110) surface. 7,19 Considering the configuration of both crystal phases, which share the same composition and similar atomic coordination configurations (Scheme 1) and expose 5-fold coordinated surface Ti sites (Ti 5c , a key active site for WOR), they may have a similar intrinsic catalytic ability.…”

“…Scheme outlines the possible pathways involved in photocatalytic WOR. ,,, In the first stage, the adsorbed water (H 2 O ad ) on the Ti 5c site undergoes deprotonation, forming an OH – species at the interface. Under photoirradiation, the OH – species can be oxidized by a photohole, leading to the formation of OH • radical, which aligns with the results of the previous results. , Next, the OH • radical can transform into the O •– radical anion on the surface by releasing a H + into the solution.…”

“…These results explain why experiments showed that OH • radicals can be detected on b-TiO 2 but not on r-TiO 2 after UV-illumination. 7,17,18,57,58 O−O Coupling Influenced by H-Bond Network. According to eq 5, the barriers associated with O−O coupling is another crucial factor impacting the selectivity of H 2 O 2 .…”

“…First, WOR involves multiple competing pathways with complex intermediates. Notably, the formation of peroxide intermediates encompasses diverse mechanisms, such as the oxo–oxo coupling of OH • radicals or O •– radicals on two metal sites, ,, alongside the water nucleophilic attack (WNA) on a M–O • species. − Subsequently, the conversion of peroxide intermediates may lead to the formation of H 2 O 2 through protonation or the production of O 2 via deprotonation. , The intricate nature of these competing reaction pathways poses a formidable challenge in discerning the mechanisms and kinetics governing H 2 O 2 and O 2 evolution. Second, the photocatalytic WOR involves intermediates in excited states, including OH • radicals, O •– radical anions, and peroxide intermediates.…”

Dual-channel synthesis of H2O2via photoelectrocatalytic water oxidation and oxygen reduction over a TaON/Ta3N5/CuI/Cu foam electrode

“…Hydrogen peroxide (H 2 O 2 ) is an important chemical reagent that plays a vital role in paper bleaching, wastewater treatment, disinfection, chemical synthesis, and energy applications. 1–7 Today, H 2 O 2 is produced industrially using the anthraquinone process, which involves multi-step hydrogenation and oxidation reactions that are highly energy-intensive and unsustainable. 8,9 Photocatalysis (PC) is a promising alternative.…”