Abstract:
Fabrication of nanocatalysts with unique architectures provides great opportunities for modulation of catalyst surface states and therefore their catalytic performances including the activity and product selectivity. In this regard, the rational design for the nanoarchitectures upon facile strategies becomes an emerging research direction lately. In this talk, two stories of hollow bimetallic nanocatalysts made by nanoarchitectonic engineering for small molecule conversions will be introduced. (1) Hollow CuAu nanoboxes with Cu-rich inner walls were synthesized for improving the NH3 Faradaic efficiency in N2RR. These beveled nanoboxes are produced in different degrees of corner and edge etching, which produces both polyhedral and concave structures. In N2RR, the binary CuAu nanoboxes enhanced NH3 production compared to individual Au and Cu nanocubes. The results of DFT calculations suggest the Cu-rich inner walls in the hollow beveled CuAu nanoboxes play a major role in their performance, by reducing the free energy DG*NNH for the potential-determining step to form *NNH (* + N2(g) + H+ + e‒ ® *NNH). (2) A one-step synthetic strategy was demonstrated for the synthesis of both closed solid and hollow framed icosahedral PdRu nanoparticles via a two-stage process of growth and dissolution. By extraction at different reaction times, icosahedral PdRu nanoparticles (INPs), concave-faceted icosahedral PdRu nanoparticles (CINPs), and icosahedral PdRu nanoframes (INFs) are obtained. Electrochemical ethanol oxidation (EOR) and CO2 reduction reactions (CO2RR) were carried out over the three types of catalysts, PdRu INPs, PdRu CINPs, PdRu INFs, as well as a commercial Pd nanoparticle (NPs), to examine their catalytic properties. PdRu INFs showed a much higher mass activity than those of PdRu INPs, PdRu CINPs and Pd NPs in EOR. PdRu INFs exhibited the high Faradaic efficiency (FE) of CO gas (34%) which suggests the expansive strain in the framework catalyst structure influences the results of CO2 conversion.