Ruthenium on Alkali-Exfoliated Ti₃(Al_0.8Sn_0.2)C₂ MAX Phase Catalyses Reduction of 4-Nitroaniline with Ammonia Borane

MAX phases are gaining increased interest in catalysis, typically for high-temperature applications. They can also be delaminated into 2D-structures, so-called MXenes, enabling better accessibility and the tuning of active site surroundings. Here we present an analogous yet different approach, using an alkaline treatment to prepare a Ti₃(Al_0.8Sn_0.2)C₂ MAX phase derivative, with an open, disordered structure. This new material, which is missing most of the larger interlayer spacing, is a good support for ruthenium particles (1.6 nm diameter). Ru on disordered MAX phase catalyses both ammonia borane hydrolysis (TOF=582 min⁻¹, 30 °C) and the reduction of 4-nitroaniline (TOF=13 min⁻¹, 45 °C). Using the former as a benchmark reaction, we show that the open disordered structure of the support promotes catalytic activity. The boost in reactivity is related to a metal-support interaction, improving the activity of metallic ruthenium. We also show here, for the first time, that supported Ru is a good catalyst for reducing nitroaniline with ammonia borane. Overall, our results reveal that disordered MAX-derivatives are promising as catalyst supports, owing to their potential for tuning the electronic properties at the metal active sites.