A sodium-hydroxide-assisted reduction approach has been developed to control the synthesis of ultrafine surfactant-free bimetallic NiPt nanoparticles (NPs) supported on nanoporous carbon, Maxsorb MSC-30. For the first time, this catalyst exerts exceedingly high catalytic activity for 100% selective conversion of hydrazine borane (HB) to hydrogen at room temperature. This remarkably facile and effective reduction approach provides a powerful entry into ultrafine alloy NPs to make full use of noble metals and achieve enhanced performance, where the compositions of the alloy can be widely adjusted and tailored. Moreover, the catalytic results open up new avenues in the effective application of HB as a promising hydrogen storage material. (Chemical Equation Presented).