Discovery of LaAlO3 as an efficient catalyst for two-electron water electrolysis towards hydrogen peroxide

Abstract

Electrochemical two-electron water oxidation reaction (2e-WOR) has drawn significant attention as a promising process to achieve the continuous on-site production of hydrogen peroxide (H2O2). However, compared to the cathodic H2O2 generation, the anodic 2e-WOR is more challenging to establish catalysts due to the severe oxidizing environment. In this study, we combine density functional theory (DFT) calculations with experiments to discover a stable and efficient perovskite catalyst for the anodic 2e-WOR. Our theoretical screening efforts identify LaAlO3 perovskite as a stable, active, and selective candidate for catalyzing 2e-WOR. Our experimental results verify that LaAlO3 achieves an overpotential of 510 mV at 10 mA cm−2 in 4 M K2CO3/KHCO3, lower than those of many reported metal oxide catalysts. In addition, LaAlO3 maintains a stable H2O2 Faradaic efficiency with only a 3% decrease after 3 h at 2.7 V vs. RHE. This computation-experiment synergistic approach introduces another effective direction to discover promising catalysts for the harsh anodic 2e-WOR towards H2O2.

Solar‐Driven Production Of Hydrogen Peroxide And Benzaldehyde In Two‐Phase System By An Interface‐Engineered Co9S8‐CoZnIn2S4 Heterostructure

“…Continuous efforts have been invested in fabricating advanced particulate photocatalysts for the synthesis of H 2 O 2 in the past few years. [12][13][14] However, particulate photocatalysts commonly suffer from low solar-to-H 2 O 2 conversion efficiency stemming from the sluggish four-electron transfer process of water oxidation. [9,15,16] As a consequence, hole sacrificial agents, such as methanol, and ethanol, are typically required to consume photogenerated holes and supply protons.…”

Hydrogen Peroxide Synthesis via Electrocatalytic Water Oxidation on sp3 and sp2 Carbon Materials Mediated by Carbonates and Bicarbonates

“…Generally, a suitable anode material for the 2e − WOR should have some prerequisite properties, including good stability under the high oxidation potential in aqueous solution, excellent electrical conductivity, and sluggish kinetics for oxygen evolution reaction. 12,13 A variety of metal oxides have been developed for H 2 O 2 generation via the 2e − WOR owing to their excellent stability under the oxidation conditions, for instance, TiO 2 , 14,15 SnO 2 , 14,16 Sb 2 O 3 , 17,18 ZnO, 19 BiVO 4 , 14,20,21 CaSnO 3 , 22 CuWO 4 , 23 and LaAlO 3 . 13 However, due to the poor conductivity of oxides, the reaction current density is relatively low, which leads to an unsatisfactory production rate of H 2 O 2 .…”

“…12,13 A variety of metal oxides have been developed for H 2 O 2 generation via the 2e − WOR owing to their excellent stability under the oxidation conditions, for instance, TiO 2 , 14,15 SnO 2 , 14,16 Sb 2 O 3 , 17,18 ZnO, 19 BiVO 4 , 14,20,21 CaSnO 3 , 22 CuWO 4 , 23 and LaAlO 3 . 13 However, due to the poor conductivity of oxides, the reaction current density is relatively low, which leads to an unsatisfactory production rate of H 2 O 2 . 2,17 Carbon materials generally possess relatively high electrical conductivity and exhibit acceptable activity, selectivity, and stability for electrochemical 2e − WOR.…”

“…Metal oxides and carbon materials are the main anode materials for producing H 2 O 2 via the 2e – WOR. Generally, a suitable anode material for the 2e – WOR should have some prerequisite properties, including good stability under the high oxidation potential in aqueous solution, excellent electrical conductivity, and sluggish kinetics for oxygen evolution reaction. , A variety of metal oxides have been developed for H 2 O 2 generation via the 2e – WOR owing to their excellent stability under the oxidation conditions, for instance, TiO 2 , , SnO 2 , , Sb 2 O 3 , , ZnO, BiVO 4 , ,, CaSnO 3 , CuWO 4 , and LaAlO 3 . However, due to the poor conductivity of oxides, the reaction current density is relatively low, which leads to an unsatisfactory production rate of H 2 O 2 . , Carbon materials generally possess relatively high electrical conductivity and exhibit acceptable activity, selectivity, and stability for electrochemical H 2 O 2 synthesis though the 2e – WOR. ,− Mavrikis and coworkers systematically investigated the electrocatalytic production of H 2 O 2 by boron-doped diamond (BDD) electrodes in bicarbonate- or carbonate-based aqueous electrolytes. − In fact, BDD has been used as the anode to electrooxidize sulfuric acid to produce peroxodisulfuric acid which further hydrolyzes to produce H 2 O 2 .…”

Fate and Reactivity of Peroxides Formed over BiVO4 Anodes in Bicarbonate Electrolytes

“…In terms of electrolyte, the first promising results were obtained by Izgorodin et al in an ionic liquid using MnO x anodes . Pioneering work by Fuku et al later established a 2 M potassium bicarbonate (KHCO 3 ) electrolyte as the best choice for anodic hydrogen peroxide production using BiVO 4 anodes, − and this has since been the established standard. , Recent reports on other anode materials such as ZnO, CaSnO 3 , or LaAlO 3 also employ this electrolyte. − …”