Nitrogen-Containing Surface Ligands Lead to False Positives for Photofixation of N2 on Metal Oxide Nanocrystals: An Experimental and Theoretical Study

Many ligands commonly used to prepare nanoparticle catalysts with precise nanoscale features contain nitrogen (e.g., oleylamine); here, it is found that the use of nitrogen-containing ligands during the synthesis of metal oxide nanoparticle catalysts substantially impacts product analysis during photocatalytic studies. These experimental results are confirmed via hybrid Density Functional Theory (DFT) computations of the materials' electronic properties to evaluate their viability as photocatalysts for nitrogen reduction. This nitrogen ligand contamination, and subsequent interference in photocatalytic studies is avoidable through the careful design of synthetic pathways that exclude nitrogen-containing constituents. This result highlights the urgent need for careful evaluation of catalyst synthesis protocols, as contamination by nitrogen-containing ligands may go unnoticed since the presence of nitrogen is often not detected or probed.