Pd and CoxPd1−x nanoparticles (NPs), synthesized using the reduction by solvent method, were loaded on SiO2 and Ti–SiO2 supports. The resulting catalysts were tested in the ammonia-borane decomposition reaction under dark and UV-vis conditions. The synergistic promotion by Co (in the NPs) and Ti (in the support), combined with the UV-vis light irradiation, enhanced the catalytic activity showing very promising TOFs values for this kind of catalysis, from 1.53 to 49.5 mol H2 per mol Pd per min. ; We thank the Spanish Ministry of Economy and Competitiveness (MINECO), Generalitat Valenciana and FEDER (Projects CTQ2015-66080-R MINECO/FEDER and PROMETEOII/2014/010) for financial support. J. G. A. thanks the MINECO for his fellowship (BES-2013-063678), with special thanks for the mobility grant of MINECO (EEBB-I-15-10219) at Osaka University.