Remarkable differences in the voltammetric response towards hydrogen peroxide, oxygen and Ru(NH 3 ) 6 3+ of electrode interfaces modified with HF or LiF-HCl etched Ti 3 C 2 T x MXene

An electrochemical study was performed on the behavior of Ti 3 C 2 T x MXenes prepared by using either HF (MXene1) or LiF/HCl as etchants (MXene2). The use of two redox probes indicates the presence of a higher negative charge density on MXene2 in comparison to MXene1. The characterization of two nanomaterials shows that titanium and fluoride are present higher by one order of magnitude at the interface of MXene2, compared to MXene1. The high Ti and F content is accompanied by a 82-fold larger (249 μA·cm −2 vs. 5.64 μA·cm −2 ) anodic peak at the peak potential near 0.4 V (vs. Ag/AgCl). Similarly, the peak current on MXene2 is 317-fold higher for the oxygen reduction at pH 7.0 (at a voltage of −0.84 V) and 215-fold higher for the reduction of H 2 O 2 at −0.89 V, when compared to MXene1. Graphical abstract Difference in electrochemical behavior of MXene prepared by HF (MXene1) and LiF/HCl (MXene2) as etchants.