Synthesis and catalytic properties of highly porous Ag-Rh nanocages

•Ag-Rh nanocages were synthesized by a facile method at 190 °C.•The formation of nanocages depends on the precursor concentration and temperature.•The walls of the Ag-Rh nanocages are highly porous.•Ag-Rh nanocages have good catalytic performance for the reduction of R6G and 4-NP.•Ag-Rh nanocages improve the H2 selectivity and TOF for hydrazine decomposition. Ag-Rh nanocages are synthesised by a facile method at 190 °C using Ag nanocubes and Na3RhCl6 as sacrificial templates and precursor, respectively. Upon introduction of Na3RhCl6 into Ag nanocube suspension in ethylene glycol (EG) with poly(vinylpyrrolidone), Rh(III) ions are reduced by EG and Ag atoms via galvanic reaction; simultaneously, the released Ag(I) ions are reduced by EG. The reduction and co-deposition of both Ag and Rh atoms result in the formation of highly porous Ag-Rh nanocages when high volume of Na3RhCl6 is introduced. The Ag-Rh nanocages with Ag:Rh atomic ratio of 54.2:45.8 exhibit good catalytic activity toward the degradation of rhodamine 6G, reduction of 4-nitrophenol, and decomposition of hydrazine. [Display omitted]