Self-Interface in Rh Nanosheets-Supported Tetrahedral Rh Nanocrystals for Promoting Electrocatalytic Oxidation of Ethanol.

Direct ethanol fuel cells hold great promise as a power source. However, their commercialization is limited by anode catalysts with insufficient selectivity toward a complete oxidation of ethanol for a high energy density, as well as sluggish catalytic kinetics and low stability. To optimize the catalytic performance, rationally tuning surface structure or interface structure is highly desired. Herein, a facile route is reported to the synthesis of Rh nanosheets-supported tetrahedral Rh nanocrystals (Rh THs/NSs), which possess self-supporting homogeneous interface between Rh tetrahedrons and Rh nanosheets. Due to full leverage of the structural advantages within the given structure and construction of interfaces, the Rh THs/NSs can serve as highly active electro-catalysts with excellent mass activity and selectivity toward ethanol electro-oxidation. The in situ Fourier transform infrared reflection spectroscopy showed the Rh THs/NSs exhibit the highest C1 pathway selectivity of 23.2%, far exceeding that of Rh nanotetrahedra and Rh nanosheets. Density function theory calculations further demonstrated that self-interface between Rh nanosheets and tetrahedra is beneficial for C-C bond cleavage of ethanol. Meanwhile, the self-supporting of 2D nanosheets greatly enhance the stability of tetrahedra, which improves the catalytic stability.