H2 evolution experiments were conducted in 37% HCl-50% H3PO2 (5:1, v/v) (concentrated acids were from Aldrich)solutions irradiated in Pyrex glass containers (36 mL capacity, 24 mL sample). After addition of the catalyst (1 g L -1 ), the sample was deoxygenated by Ar bubbling (20 min) to obtain anoxic conditions and irradiated under magnetic stirring for 4 hours.