Near‐100% C1‐Pathway Selective Ethanol Oxidation on Turing‐Type Pd‐Based Crystalline/Amorphous Heterointerfaces

Abstract

ABSTRACT Direct ethanol fuel cells are hindered by the ethanol oxidation reaction (EOR) that favors the low‐efficiency C2 pathway over the desirable C1 pathway. Here, we report a catalyst design integrating an ultrathin Turing‐type nanonet with a Pd‐based crystalline/amorphous (C/A) heterointerface, achieving a near‐complete C1‐pathway selectivity of 97.1% for alkaline EOR, which is the highest reported to date. Inspired by spatially decoupling C─C cleavage and CO oxidation, we engineer two intimately integrated phases: strained interstitial‐carbon‐doped PdO (C int ‐PdO) enriched with oxygen vacancies and defective amorphous PdC x (a‐PdC x ). This heterostructure is realized via a “carbon engineering” strategy combining salt‐melt templating with secondary annealing. Atomic‐resolution studies confirm atomically sharp C/A interfaces and the highly unsaturated a‐PdC x phase. In situ Fourier‐transform infrared spectroscopy (FTIR) directly visualizes CO 2 emergence at ultralow overpotentials, while high‐performance liquid chromatography (HPLC) verifies the near‐complete C1 pathway. Density functional theory (DFT) reveals a dual‐cooperative mechanism: C int ‐PdO steers the EOR toward C1 pathway by facilitating CH 3 CO* dehydrogenation and subsequent C─C cleavage via CH 2 CO*, thereby suppressing acetate formation; concurrently, a‐PdC x dramatically accelerates CO oxidation and may also contribute to C─C cleavage via an alternative direct CH 3 CO* pathway. This work establishes carbon‐engineered C/A heterointerfaces as a powerful platform for overcoming the EOR selectivity bottleneck.