Water Enables Lattice Oxygen Activation of Transition Metal Oxides for Volatile Organic Compound Oxidation

Abstract

A small amount of water can enhance the catalytic combustion activity of volatile organic compounds (VOCs) on transition metal oxides (TMOs), but its intrinsic mechanism is still controversial. Herein, we systematically demonstrate that water molecules can constantly activate lattice oxygen of transition metal oxides to form hydroxyl species theoretically and experimentally. The oxygen atoms of the generated hydroxyl species possess a weak bonding strength with circumjacent metal atoms to easily escape from the surface and attack electron-deficient carbon atoms of VOCs due to their comparatively stronger nucleophilicity, leaving abundant oxygen vacancies as the active sites for subsequent molecular oxygen activation. This work helps us deeply understand the role of water in lattice oxygen activation of transition metal oxides and provides direction for water-related catalysis, such as catalytic VOC combustion, water splitting, water–gas shift reactions, and corrosion.