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

Abstract 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.