Mitigating Hydrogen Poisoning for Robust Ammonia-to-Hydrogen Conversion over Photothermal Catalysts

Ammonia is recognized as a highly promising candidate for hydrogen storage, and its decomposition to hydrogen has attracted increasing attention. Here, photothermal catalysts composed of Ni, Au, or Ru with γ-Al 2 O 3 support have been designed for the NH 3 -to-H 2 conversion. Ru/γ-Al 2 O 3 exhibits the highest NH 3 conversion (84.8%) and H 2 yield (1.7 mol·g cat –1 ·h –1 ) at a gas hourly space velocity (GHSV) of 30 L·g cat –1 ·h –1 . H 2 desorption was found to be slower than N 2 desorption over Ru/γ-Al 2 O 3 in the dark. The hydrogen poisoning phenomenon was mitigated during the photothermal catalytic process, compared with the thermal catalytic process. Hot carriers generated in the photothermal catalysts were proven to effectively cleave Ru–H* bonds under illumination. Moreover, Ru/γ-Al 2 O 3 photothermal catalyst was found to inhibit catalyst aggregation, resulting in robust NH 3 -to-H 2 conversion over 1200 h under illumination.