Single‐Atom or Dual‐Atom in TiO2 Nanosheet: Which is the Better Choice for Electrocatalytic Urea Synthesis?

As rising star materials, single‐atom and dual‐atom catalysts have been widely reported in the electro‐catalysis area. To answer the key question: single‐atom and dual‐atom catalysts, which is better for electrocatalytic urea synthesis? we design two types of catalysts via a vacancy‐anchorage strategy: single‐atom Pd1−TiO2 and dual‐atom Pd1Cu1−TiO2 nanosheets. An ultrahigh urea activity of 166.67 molurea molPd−1 h1 with the corresponding 22.54 % Faradaic efficiency at −0.5 V vs. reversible hydrogen electrode (RHE) is achieved over Pd1Cu1−TiO2, which is much higher than that of Pd1−TiO2. Various characterization including an in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and theoretical calculations demonstrate that dual‐atom Pd1Cu1 site in Pd1Cu1−TiO2 is more favorable for producing urea, which experiences a C−N coupling pathway with a lower energy barrier compared with Pd1 in Pd1−TiO2. [ABSTRACT FROM AUTHOR]