[H]-mediated enhancement of the Fenton reaction over a Pd/UiO-66(Zr)-F₄ catalyst

A [H]-accelerated catalytic Fenton system was developed using Pd/UiO-66(Zr)-F₄ as the catalyst. This system enabled the regeneration of Fe²⁺ and facilitated the continuous generation of both ·OH and ¹O₂ through [H]-mediated electron transfer at ambient temperature and pressure. Under the conditions of 0.2 g L^-1 catalyst (Pd loading 0.516 wt%), 25 μM Fe²⁺, 60 mL min^-1 H₂ flow (as the [H] source), 20 mM H₂O₂, and pH 3, approximately 89% of carbamazepine (initial concentration 20 mg L^-1) was degraded within 3 h using trace iron. However, the catalytic activity of Pd/UiO-66(Zr)-F₄ gradually declined from 89% to 53% over six reaction cycles. This decrease was likely due to loss of specific surface area caused by microstructural degradation associated with hydrogen spillover effects.