Metastable Hexagonal Phase SnO₂ Nanoribbons with Active Edge Sites for Efficient Hydrogen Peroxide Electrosynthesis in Neutral Media

Abstract

Electrochemical two-electron oxygen reduction reaction (2 e À ORR) to produce hydrogen peroxide (H 2 O 2 ) is a promising alternative to the energetically intensive anthraquinone process. However, there remain challenges in designing 2 e À ORR catalysts that meet the application criteria. Here, we successfully adopt a microwave-assisted mechanochemical-thermal approach to synthesize hexagonal phase SnO 2 (h-SnO 2 ) nanoribbons with largely exposed edge structures. In 0.1 M Na 2 SO 4 electrolyte, the h-SnO 2 catalysts achieve the excellent H 2 O 2 selectivity of 99.99 %. Moreover, when employed as the catalyst in flow cell devices, they exhibit a high yield of 3885.26 mmol g À 1 h À 1 . The enhanced catalytic performance is attributed to the special crystal structure and morphology, resulting in abundantly exposed edge active sites to convert O 2 to H 2 O 2 , which is confirmed by density functional theory calculations.

Rational Design of Oxygen Species Adsorption on Nonnoble Metal Catalysts for Two‐Electron Oxygen Reduction

“…It provides a comparative analysis of H 2 O 2 selectivity both before and after structural tuning, elucidating the intrinsic correlation between the oxygen species of the catalytic site and catalyst performance. [79][80][81][82][83][84] A comparison of the performance of typical transition metal catalysts before and after adjustment of the oxygen adsorption state is shown in Figure 4b.…”

“…Reproduced with permission. [82] Copyright 2023, Wiley-VCH. adsorption of oxygen, triggering the activation and dissociation of O─O bonds.…”

“…Hexagonal phase tin dioxide (h-SnO 2 ) nanoribbons exhibited an outstanding H 2 O 2 selectivity of 99.99% in 0.1 M Na 2 SO 4 electrolyte, which is significantly higher than that of rutile phase SnO 2 . [82] In summary, the pursuit of highly selective 2e − ORR catalysts can be effectively realized by manipulating the adsorption state of oxygen intermediates at the active sites of diverse transition metal catalysts. For transition metal catalysts, optimization of the atomic distance, coordination environment, and crystal configuration at the metal surface interface proved to be effective strategies for adjusting the oxygen intermediate adsorption state.…”

Carboxylated Hexagonal Boron Nitride/Graphene Configuration for Electrosynthesis of High‐Concentration Neutral Hydrogen Peroxide

“…[6a,7] This dilemma becomes especially acute under the neutral electrolyte. [8] Compared with the strong acid or alkaline condition, the electrosynthesis of neutral H 2 O 2 is advantageous to inhibit the H 2 O 2 decomposition and equipment corrosion for favorable storage and transportation. [9] Besides, the majority of the agents for stabilizing H 2 O 2 products are near neutral.…”

Strain and Surface Engineering of Multicomponent Metallic Nanomaterials with Unconventional Phases

“…To date, unconventional phases have been successfully achieved in a variety of nanomaterials, such as metals, metal oxides, metal hydroxides, metal–metal/nonmetal alloys, intermetallic compounds, and transition metal dichalcogenides (TMDs). ,,− Herein, we choose metals and TMDs as representatives to introduce their conventional and unconventional phases. As displayed in Figure a–c, the ball models visualize the unit cells commonly found in metals including face-centered-cubic (fcc), 2H and 4H types of hexagonal-close-packed (hcp), and body-centered-cubic (bcc) crystal phases.…”