Controllable CO₂ Reduction or Hydrocarbon Oxidation Driven by Entire Solar via Silver Quantum Dots Direct Photocatalysis

Abstract

The current solar-chemical-industry based on semiconductor photocatalyst is impractical. Metal catalysts are extensively employed in thermal- and electro-catalysis industries, but unsuitable for direct-driven photocatalysis. Herein, silver quantum dots (Ag-QDs) are synthesized on support via an in situ photoreduction method, and in situ photocatalysis temperature programmed dynamics chemisorption desorption analyses are designed to demonstrate that Ag-QDs should be the actual photocatalytic sites. The surface plasmon resonance of Ag-QDs could harvests entire visible solar, and the plasmon-driven charge-transfer exhibits opposite directions at the interface when supports are different. Consequently, Ag-QDs could be alternatively regulated as oxidation or reduction active centers. Furthermore, Ag-QDs excite electron tunneling transfer with adsorbate, which does not generate high-energy free-radical intermediates. As a result, the efficiencies of hydrocarbon photooxidation and CO₂ photoreduction are improved in several orders of magnitude. Evidently, the Ag-QDs direct photocatalytic technology greatly promotes solar-chemical-industry applications.