Constituting plasmonic-metal nanostructures is an efficient way in the design and development of active photocatalytic systems. Here we demonstrate a simple one-step reduction process that can in situ grow plasmonic silver nanoparticles on the surface of AgTaO3. The exsolution of silver out of AgTaO3 does not seem to have a significant impact on the crystal integrity, whilst its visible light sensitivity is greatly enhanced. Such Ag nanoparticles decorated AgTaO3 system showed improved photocatalytic hydrogen evolution both under visible and full range irradiation. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.