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

Abstract

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(Al0.8Sn0.2)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.

Selective reduction of oxalic acid to glycolic acid at low temperature in a continuous flow process

“…In our previous work, 31 we established suitable reaction conditions for the reduction of oxalic acid to glycolic acid in a stirred batch reactor. Here, we aim to translate the reaction to a continuous flow process in a trickle-bed reactor (Fig.…”

“…Such oxidation was observed earlier for supported Ru catalysts. 31 The carbon support is predominantly amorphous and stays unaltered during the reaction as conrmed by the broad peaks from 2q 15-30°and 2q 40-45°. 32 In the EDS analysis, however, we also found signicant amounts of silicon (15 wt%), iron (3 wt%) and aluminum (6 wt%) apart from RuO 2 on the catalyst.…”

Oxalic acid hydrogenation to glycolic acid: heterogeneous catalysts screening

“…Ruthenium is widely used as a hydrogenation catalyst. 35,[44][45][46] As carboxylic acid reduction depends on the adsorption of the acid group on the catalyst surface, we also drew inspiration from work on other substrates such as the reduction of lactic acid, adipic acid but also fatty esters or aldehyde reductions. Takeda et al, investigated the hydrogenation of lactic acid to 1,2-propanediol using modified ruthenium on a carbon catalyst containing a small percentage of molybdenum.…”

“…This does not come as a surprise as the benefits of adding tin to ruthenium based catalysts have been described before. [40][41][42][43][44][45][46] In bi-or multi-metallic catalysts, one should differentiate between the two metals forming alloys or being present as separate metal and metal oxides species which can benefit the reaction due to the geometric or electronic effects. For Ruthenium and Tin systems both have been proposed and thus we aim a in-depth investigation of the role on tin addition in this case.…”

Strong Electronic Metal–Support Interaction Augments Hydrogen Evolution over hcp-Ni/In2O3 with Ultrasound-Assisting Dehydrogenation of Ammonia Borane

“…Additionally, the catalytic performance of metal NPs is related to their size and dispersion, meanwhile the anti-agglomeration of nanocatalysts is nontrivial in practice. Stabilizing metal nanocatalysts can be realized by anchoring them onto metal oxide supports. , Among the many oxides, In 2 O 3 nanomaterials with high specific surface area, rich porosities, and designable functionalities have attracted intensive attention. , Therefore, the construction of supported metastable Ni nanocatalysts with electronic metal–support interaction (EMSI) toward efficient dehydrogenation of AB is highly desirable. − …”