Local coordination environment triggers key Ni-O-Si copolymerization on silicalite-2 for dry reforming of methane

The development of dry reforming of methane (DRM) catalysts with good Ni loading, while retaining high metal dispersion is a critical issue, given the harsh industrial-relevant conditions. Here, we demonstrate the impact of the local coordination environment on the DRM activity of Ni-silicalite-2 (Ni-S2) catalysts. The grafted Ni(II) intermediates with high Ni-O-Si copolymerization (coordination number ratio Si: Ni=2.28) are discovered to redisperse Ni sites, even at 10 wt% Ni loading. Then, the partial S2 recrystallizes into new SiO2-nanowires to anchor Ni nanoparticles, via an ethylenediamine-assisted dissolution-recrystallization (enDR). Compared to the typical Ni-S2 catalyst with Ni phyllosilicate (CN ratio Si: Ni＜1), the Ni-S2-enDR shows high dispersion and stability at 800 °C and 450 L gcat−1 h−1, exhibiting negligible coke deposition and no growth of 4.25 nm Ni nanoparticles. The atomic level insights in nickel and silicon coordination reported in this work provide an instructive way of designing stable DRM catalysts. [Display omitted] •The Ni-O-Si copolymerization is tuned via the local distribution of hydroxy Ni and Si.•A SiO2 nanowire is prepared by the high CN ratio Si: Ni of 2.28 grafted Ni(II) as intermediates.•The grafted Ni(II) structures redisperse and anchor Ni sites, even at a high Ni loading of 10%.•The Ni-S2-enDR catalysts with SiO2 nanowires have strong metal-support interaction.•The Ni-S2-enDR catalysts showed high activity and stability at high GHSV and temperature.