Nuclear chemistry

Hydroxyl radical

Catalysis

Process (computing)

Electrochemistry

Photochemistry

Hydrogen peroxide

Operating system

Transition metal

Computer science

Inorganic chemistry

Physical chemistry

Organic chemistry

Radical

Chemistry

Electrode

Adduct

Environmental Science & Technology

Hydroxyl radical (•OH) can hydroxylate or dehydrogenate organics without forming extra products and is thereby expediently applied in extensive domains. Although it can be efficiently produced through single-electron transfer from transition-metal-containing activators to hydrogen peroxide (H2O2), narrow applicable pH range, strict activator/H2O2 ratio requirement, and byproducts that are formed in the mixture with the background matrix necessitate the need for additional energy-intensive up/downstream treatments. Here, we show a green Fenton process in an electrochemical cell, where the electro-generated atomic H* on a Pd/graphite cathode enables the efficient conversion of H2O2 into •OH and subsequent degradation of organic pollutants (80% efficiency). Operando liquid time-of-fight secondary ion mass spectrometry verified that H2O2 activation takes place through a transition state of the Pd–H*–H2O2 adduct with a low reaction energy barrier of 0.92 eV, whereby the lone electron in atomic H* can readily cleave the peroxide bridge, with •OH and H2O as products (ΔGr = −1.344 eV). Using H+ or H2O as the resource, we demonstrate that the well-directed output of H* determines the pH-independent production of •OH for stable conversion of organic contaminants in wider pH ranges (3–12). The research pioneers a novel path for eliminating the restrictions that are historically challenging in the traditional Fenton process.

pH-Independent Production of Hydroxyl Radical from Atomic H*-Mediated Electrocatalytic H<sub>2</sub>O<sub>2</sub> Reduction: A Green Fenton Process without Byproducts

pH-Independent Production of Hydroxyl Radical from Atomic H*-Mediated Electrocatalytic H2O2 Reduction: A Green Fenton Process without Byproducts

pH-Independent Production of Hydroxyl Radical from Atomic H*-Mediated Electrocatalytic H₂O₂ Reduction: A Green Fenton Process without Byproducts