Tandem synergistic photocatalytic CO₂ reduction to ethylene over a Pd/W₁₈O₄₉ nanoporous structure

Photocatalytic conversion of CO₂ into C₂H₄ offers a promising route toward carbon neutrality; however, it remains limited by low C₁ intermediate coverage and sluggish CC coupling kinetics. To address this challenge, a nanoporous W₁₈O₄₉ (WO) photocatalyst anchored with Pd nanoparticles (NPs) was designed, achieving an ethylene (C₂H₄) production rate of 13.1 μmol·g^-1·h^-1 and an electron selectivity of 78.3%, using water vapor as the proton source. The nanoporous architecture provides abundant active sites that facilitate CO₂ adsorption and activation, thereby ensuring sufficient C₁ coverage. Density functional theory (DFT) calculations reveal that *CO intermediates are initially generated at the W sites of WO through CO₂ activation and subsequently migrate to Pd NPs, where they are hydrogenated to *CHO and undergo *CO-CHO coupling via an exergonic process, ultimately promoting C₂H₄ evolution. This work demonstrates a tandem synergistic strategy for the photocatalytic conversion of CO₂ into C₂ products using a metal/semiconductor nanoporous photocatalyst.