Electrochemical etching of MAX phases: MAX phase powder (1g, 500 mesh, Nanoplexus) and HBF4 (250 mL, 24% in H2O) was added to the graphite crucible. A platinum wire was used as the counter electrode. The suspension was rested for 30 minutes until the electrolytes reached the desired temperature and all the MAX phases powder settled at the bottom of the crucible. +1 V was applied for 28 hours at 35 °C. After electrochemical etching, the MXene was washed by deionized water via vacuum filtration. The MXene was dried at 80 °C under vacuum for 15 hours. The dried EE-MXene was stored at 3 °C until further characterization application. The average yield of EE-Ti3C2 and EE-Ti3CN obtained was between 85 % and Chemical etching of MAX phases with HBF4: the chemical etching with HBF4 was carried out similarly to the electrochemical etching, but without applying voltage.