Table 3. Effects of Isotopic Substitution on Rate Constants of H₂O₂ and H₂O Formation on 2 and 25 nm Au Nanoparticles Supported on TiO₂ (200 kPa H₂ or 200 kPa D₂, 60 kPa O₂, 278 K).

reaction	Au nanoparticles
	2 nm	25 nm
H2 + O2 → H2O2	1.5 ± 0.1	1.6 ± 0.1
H2 + 1/2O2 → H2O	1.5 ± 0.3	1.5 ± 0.3