Abstract
<title>Abstract</title> <p>This research introduces a novel, high-performance Ni-doped γ-AlO multifunctional catalyst (MFC) for the CO methanation reaction (CMR). The catalysts are designated as AN where x and y are the mass ratios between the [NH]CO additive for γ-AlO (A) and Ni (N) precursor, respectively, used in the synthesis. This design integrates multiple distinct functions, including catalysis, adsorption, and stabilization, into a single nanomaterial. The AN features strong metal-support interaction (MSI) interlayers with a high density of both Lewis acid (surface hydroxyls: OH*) and Lewis base sites (oxygen vacancies: OVs). The optimized AN composite catalyst exhibits the best CMR performance, achieving a 92.1% conversion of 1 vol% CO with an 82.8% yield at 400°C. This corresponds to a high CH formation rate of 19.9 mmol g h and a turnover frequency of 0.25 s⁻¹ at 400°C. The catalyst's irregular, defect-rich structural morphology provides evidence of synergistic acid-base pairs, originating from adjacent OH* groups and OVs on the γ-AlO surface. The strong MSI stemming from the NiAlO interface ensures the stabilization of ultra-fine Ni nanoparticles, preventing their sintering under reaction conditions. This enhancement in textural and electrical properties improves the accessibility of CO to the exposed Ni active sites, promoting efficient reaction kinetics and CMR performance. This synergistic integration of multiple chemical and structural functions within a single material provides a compelling strategy to facilitate the development of sustainable, chemically tailored MFMs with high potential to surpass current industrial CMR benchmarks.</p>