通过反应界面微环境调控促进甲酸驱动的氧气还原合成过氧化氢

Boosting hydrogen peroxide production in formic acid-driven oxygen reduction via regulating the microenvironment of reaction interfaces

甲酸驱动的双电子氧还原是在温和条件下合成过氧化氢(H_(2)O_(2))的一种很有前途的方法.然而,在传统的催化体系中,反应物O_(2)在固体/液体两相反应界面处的浓度通常较低,限制了反应动力学和H_(2)O_(2)的产率.在这一工作中我们通过将模型催化剂Pt-TiO_(2)沉积在疏水多孔碳基底上,构建了具有气液固三相界面微环境的催化体系.基于这种三相体系,O_(2)能够从空气中快速输送至反应界面,从而大大提高其在反应区的浓度.与传统的固液两相催化体系相比,三相体系中的H_(2)O_(2)的生成速率常数提高了10倍以上.这项工作突出了反应界面调控对催化反应性能的重要影响,为开发高效H_(2)O_(2)合成体系提供了思路.

The two-electron oxygen reduction driven by formic acid based on metal catalysts is a promising approach for H_(2)O_(2)synthesis under mild conditions.However,in conventional catalytic systems,the concentration of reactant O_(2)at the solid/liquid diphase reaction interface is generally low,which restricts the reaction kinetics and the yield of H_(2)O_(2).Inspired by the natural non-wetting surfaces,we describe here a catalytic system with an air-liquid-solid triphase interface microenvironment for efficient H_(2)O_(2)generation in formic acid-driven oxygen reduction.The triphase system was fabricated by immobilizing Pt-decorated TiO_(2)(Pt-TiO_(2)),a model catalyst on a hydrophobic porous carbon substrate.Such a triphase system allows sufficient O_(2)to be rapidly delivered from the air phase,greatly enhancing its concentration at the reaction zone.We found the H_(2)O_(2)formation rate constant was increased by more than 10-fold in comparison with a conventional solid/liquid diphase catalytic system.In addition,the design principle is applicable to a wide range of catalysts.This work provides an exploratory platform for the further development of high-efficiency H_(2)O_(2)generation systems.