Electron‐Rich Nickel Enabled by Charge Transfer in Multimetal Nanostructures for Efficient Ammonia‐to‐Hydrogen Conversion

ABSTRACT Achieving noble‐metal‐like reactivity in earth‐abundant catalysts requires materials platforms that can simultaneously stabilize active sites and program their electronic states. Ammonia‐to‐hydrogen conversion is a demanding example, because Ru‐free catalysts must overcome the intrinsically sluggish kinetics of ammonia decomposition. Here, we report a catalyst design that couples precursor‐level cation mixing and active‐site dispersion with charge‐transfer engineering of Ni to address this challenge. Density functional theory calculations identify Cr as the most effective electron‐donating promoter for Ni among metal cations incorporable into the precursor framework. Guided by this prediction, we construct a NiCrAl reduced mixed‐metal oxide catalyst in which atomically mixed precursors stabilize highly dispersed Ni species, while Cr‐to‐Ni charge transfer generates electron‐rich Ni active sites. Multiscale spectroscopic analyses verify this electronic modulation, and combined theoretical and in situ mechanistic analyses indicate that electron‐rich Ni favors NH 3 adsorption in a reaction‐relevant Lewis‐acid configuration, favorably modifies the dehydrogenation energetics, and weakens N 2 binding to facilitate product desorption. NiCrAl‐RMMO reaches 95.5% NH 3 conversion at 550°C and 22.83 mmol H 2 g cat −1 min −1 at 500°C, with stable operation over 100 h. More broadly, this work establishes charge‐transfer engineering in LDH‐derived mixed‐metal nanostructures as a general strategy for designing high‐performance, Ru‐free catalysts for ammonia‐to‐hydrogen conversion.