Highly selective aldehyde coupling on the heterointerface of molybdenum selenide and graphdiyne

The highly negative reduction potential prevents the selective coupling of two aldehydes to construct C─C bonds and hinders the formation of ketyl radicals. However, this important comprehensive issue remains unsolved. Here, we report the efficient activation of aldehydes by the in situ growth of a molybdenum selenide-graphdiyne heterointerface structure, allowing an aldehyde molecule to be selectively coupled with another aldehyde at room temperature and ambient pressure. High-resolution transmission electron microscopy and scanning transmission electron microscopy (HAADF-STEM) images reveal the formation of high-density active sites at the interface structure. The synchrotron x-ray photoelectron spectroscopy, x-ray absorption spectroscopy, and electron paramagnetic resonance spectroscopy results confirmed the selective formation of ketyl radicals. The noninteger charge transfer between graphdiyne and metal atoms promotes the continuous selectivity and efficient activation of aldehydes and C─C coupling of ketyl radicals. The ultrahigh selectivity of 2-furaldehyde for hydrofurion reached 92 ± 2%, while the turnover frequency reached 57 ± 4 per second.