Cheese-like Ti₃C₂ for enhanced hydrogen storage

MXenes are highly promising in efficient Mg-based hydrogen storage but their activity is insufficient due to the low efficiency of active sites. Here, for the first time, we propose a facile oxidation-etching-oxidation strategy to expose and optimize abundant internal active sites in a typical MXene (Ti₃C₂), avoiding additional introduction of active metal sites or complex structural optimization. The obtained cheese-like Ti₃C₂ with Ti/TiO₂ activity sites enriched at the edge of through holes exhibits much better performance in terms of dehydrogenation temperature (from 190 °C) as well as rate in initial 10 min at 250 °C (0.37 wt%/min) than ordinary Ti₃C₂ when applied in Mg-based hydrogen storage. Compared to ordinary Ti₃C₂, the dehydrogenation temperature is 60 °C decreased and rate increases to 2-fold, respectively. This work elucidates that significantly enhanced hydrogen storage performance of MXenes can be realized by exposing abundant internal edge active sites via a facile oxidation-etching-oxidation strategy.