Spiny Rhombic Dodecahedral CuPt Nanoframes with Enhanced Catalytic Performance Synthesized from Cu Nanocube Templates

Platinum was coated on the surfaces of copper nanocubes to form Cu-CuPt core-alloy-frame nanocrystals with a rhombic dodecahedral (RD) shape. Co-reduction of Pt²⁺ ions and residual Cu⁺ ions in the supernatant of the Cu nanocube solution followed by the interdiffusion of Cu and Pt atoms over the core-shell interface allowed their formation. Growth in the «100» directions of the {100}-terminated Cu nanocubes resulted in the {110}-faceted rhombic dodecahedra. By the introduction of additional Pt precursor, the {100} vertices of the Cu-CuPt RD nanocrystals could be selectively extended to form spiny CuPt RD nanocrystals. After removing the Cu core template, both CuPt alloy RD and spiny CuPt alloy RD nanoframes (NFs) were obtained with Pt/Cu ratios of 26/74 and 41/59, respectively. Abundant surface defects render them highly active catalysts due to the open frame structure of both sets of NFs. The spiny RD NFs showed superior specific activity toward the oxygen reduction reaction, 1.3 and 3 times to those of the RD NFs and the commercial Pt/C catalysts, respectively. In 4-nitrophenol reduction, both NFs displayed better activity compared to commercial Pt NPs in the dark. Their activities were improved ∼1.3 times under irradiation of visible light, attributed to the effect of LSPR enhancement by the Cu-rich skeleton.