Ni ^δ+ Atoms Anchored In Situ on Ultrathin Ni‐Phyllosilicate Nanosheet Ensure High‐Efficient CO ₂ Reduction into CO at Moderate‐Low Temperature

Ni-based catalysts are considered to be promising candidates for moderate-low temperature (200-400 °C) reverse water-gas shift (MLT-RWGS) as an important CO₂ reduction pathway. However, their high activation properties for CO inevitably lead to severe methanation at high CO₂ conversion, creating an activity-selectivity trade-off and unsatisfactory CO yields. Here, a novel supported Ni-based catalyst is deveolped, consisting of abundant Ni^δ+ atoms anchored in situ on ultrathin Ni-phyllosilicate nanosheet (a-Ni^δ+-PSNS(400), 0< δ ≤1). The a-Ni^δ+-PSNS(400) break activity-selectivity trade-off and achieve high CO selectivity (92%) toward at a formation rate of 21.0 mmol_CO h^-1 gcat^-1, outdistancing those of all prevailing Ni-based catalysts for MLT-RWGS. Such catalytic performance is attributed to unique geometric/electronic effects of a-Ni^δ+-PSNS(400), i.e., exposed monodisperse Ni^δ+ atoms with low electron density on ultrathin Ni-phyllosilicate nanosheet. The ultrathin nanosheet enables anchored Ni^δ+ atoms to fully expose and disperse, boosting atom-utilization efficiency and atom-synergistic effects, endowing them with high catalytic activity; while low electron density of Ni^δ+ atoms extremely weakens their chemical adsorption of CO, preventing further CO hydrogenation into CH₄, which ensures their high CO selectivity. This work provides new insights into the design of active microstructures of high-performance Ni-based catalysts for synchronous high activity-selectivity.