Ionic liquid modifying conductivity and hydrophobicity of B4C for enhanced electrosynthesis of H2O2

A versatile and effective surface modification method using ionic liquid to improve the 2e− ORR performance for H2O2 production is reported, which can simultaneously improve the conductivity and hydrophobicity, resulting in highly active electrocatalysts with high H2O2 selectivity and good stability. [Display omitted] •Interfacial engineering strategy of non-metallic catalysts for efficient electrosynthesis H2O2.•Emphasizing the role of ionic liquid to improve both hydrophobicity and conductivity in interface engineering.•High conductivity resulting in high H2O2 selectivity (96%).•Hydrophobic three-phase interface leading to good stability (10-cycle test in a Flow Cell reactor).•Ionic liquid modification making GDE robust flood-proof ability. Electrosynthesis of hydrogen peroxide (H2O2) via two-electron oxygen reduction reaction (2e− ORR) is an attractive energy-efficient and decentralized alternative to the conventional anthraquinone process. However, designing non-precious metal catalysts with high activity, selectivity and stability is a great challenge. Here, we report a facile and effective approach to improve the catalytic performance of commercial boron carbide (B4C) by loading ionic liquid (IL), which exploits the complementary properties of high electrical conductivity and hydrophobicity of IL. The B4C catalyst with optimal IL loading possesses the highest conductivity and O2 adsorption, exhibiting high H2O2 selectivity in both neutral (∼96 %) and alkaline (∼93 %) electrolyte, which are nearly ∼34 % and ∼19 % higher than pristine B4C, respectively. Moreover, its production rate is ∼1.5 times that of pristine B4C at 130 mA cm−2 current density, resulting in a high concentration of H2O2 (5.93 wt%) produced in flow-cell reactor. The long-term cycle test demonstrates the desirable stability of IL@B4C/GDE, which is attributed to the high hydrophobicity and tight bonding between IL@B4C and the substrate, giving a strong flood-proof capability at the three-phase interface and avoiding rapid flooding by the electrolyte. This work provides new insights into designing non-precious metal electrocatalysts for efficient electrosynthesis of H2O2, emphasizing the role of IL in interface engineering.