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Electrochemical and electrocatalytic properties of a class of layered materials known as MAX and MAB phases have yet to gain interest in the scientific community. Herein, electrochemical and toxicity studies of six MAX and MAB phases (Ti 2 AlC, Ti 2 AlN, Ti 3 AlC 2 , Ti 3 SiC 2 , Cr 2 AlB 2 , and MoAlB) were explored. The materials were found to possess high heterogeneous electron transfer (HET) rates, enhanced electrochemical sensing of ascorbic acid and uric acid, and promising electrocatalytic performances toward hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). MAB phases possessed better electrochemical properties than did MAX phases. In addition, in vitro cytotoxicity studies toward various human cells found near negligible toxicity toward the cells tested deeming them safe for handling and biocompatible for future biological applications. Therefore, MAX and MAB phases can be regarded as safe layered materials for potential electrochemical applications.

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Submicron Ti2AlC MAX phase powder was synthesized by molten salt shielded synthesis (MS3) using a Ti:Al:C molar ratio of 2:1:0.9 at a process temperature of 1000°C for 5  hours. The synthesized powder presented a mean particle size of ~0.9 µm and a purity of 91 wt. % Ti2AlC, containing 6 wt. % Ti3AlC2. The Ti2AlC powder was sintered by pressureless sintering, achieving a maximal relative density of 90%, hence field‐assisted sintering technology/spark plasma sintering was used to enhance densification. The fine‐grained microstructure was preserved, and phase purity of Ti2AlC was unaltered in the latter case, with a relative density of 98.5%. Oxidation was performed at 1200°C for 50 hours in static air of dense monolithic Ti2AlC with different surface finish, (polished, ground and sandblasted) which resulted in the formation of an approx. 8 µm thin aluminum oxide (Al2O3) layer decorated with titanium dioxide (rutile, TiO2) colonies. Surface quality had no influence on Al2O3 scale thickness, but the amount and size of TiO2 crystals increased with surface roughness. A phenomenon of rumpling of the thermally grown oxide (TGO) was observed and a model to estimate the extent of deformation is proposed.