Direct Polyethylene Photoreforming into Exclusive Liquid Fuel over Charge-Asymmetrical Dual Sites under Mild Conditions.

Abstract

Direct polyethylene photoreforming to high-energy-density C₂ fuels under mild conditions is of great significance and still faces a huge challenge, which is partly attributed to the extreme instability of *CH₂CH₂ adsorbed on the traditional catalysts with single catalytic sites. Herein, charge-asymmetrical dual sites are designed to boost the adsorption of *CH₂CH₂ for direct polyethylene photoreforming into C₂ fuels under normal temperature and pressure. As a prototype, the synthetic Zr-doped CoFe₂O₄ quantum dots with charge-asymmetrical dual metal sites realize direct polyethylene photoreforming into acetic acid, with 100% selectivity of liquid fuel and the evolution rate of 1.10 mmol g^-1 h^-1, outperforming those of most previously reported photocatalysts under similar conditions. <i>In situ</i> X-ray photoelectron spectra, density-functional-theory calculations, and control experiments reveal the charge-asymmetrical Zr-Fe dual sites may act as the predominate catalytic sites, which can simultaneously bond with the *CH₂CH₂ intermediates for the following stepwise oxidation to form C₂ products.