Highly Selective Photocatalytic Synthesis of Acetic Acid at 0-25 °C.

Abstract

Acetic acid (AA), a vital compound in chemical production and materials manufacturing, is conventionally synthesized by starting with coal or methane through multiple steps including high-temperature transformations. Here we present a new synthesis of AA from ethane through photocatalytic selective oxidation of ethane by H₂O₂ at 0-25 °C. The catalyst designed for this process comprises g-C₃N₄ with anchored Pd₁ single-atom sites. In situ studies and computational simulation suggest the immobilized Pd₁ atom becomes positively charged under photocatalytic condition. Under photoirradiation, the holes on the Pd₁ single-atom of OH-Pd₁ ${}^{\oplus }$ /g-C₃N₄ serves as a catalytic site for activating a C-H instead of C-C of C₂H₆ with a low activation barrier of 0.14 eV, through a concerted mechanism. Remarkably, the selectivity for synthesizing AA reaches 98.7 %, achieved under atmospheric pressure of ethane at 0 °C. By integrating photocatalysis with thermal catalysis, we introduce a highly selective, environmentally friendly, energy-efficient synthetic route for AA, starting from ethane, presenting a promising alternative for AA synthesis. This integration of photocatalysis in low-temperature oxidation demonstrates a new route of selective oxidation of light alkanes.