Ultrafine and highly dispersed Pd nanoparticles have drawn considerable attention with high activity, selectivity and atomic efficiency. In this paper, amorphous Pd(Ⅱ)-complex solid spheres with ~ 5 nm Pd nanoparticles loaded on were successfully achieved through a simple and gentle one-pot solution method with vitamin B1 simultaneously as complexing agent and reducing agent. An ultrathin mesoporous SiO₂ shell was then coated at the surface of Pd(Ⅱ-0) spheres as the armor which could prevent the dissolution of Pd(Ⅱ) during the catalytic process. The combination of Pd(Ⅱ) and Pd(0) endowed Pd(Ⅱ-0)@m-SiO₂ catalyst an excellent performance in eco-friendly aqueous media Suzuki reactions. The high activity, productivity and recyclability were all comparable with the best Pd catalysts ever reported. The ingenious formation of amorphous Pd(Ⅱ)/crystal Pd(0) with enhanced catalytic performances provides a new, scalable strategy to practical promotion of Suzuki cross-coupling reactions.