Atomic layers of ruthenium oxide coupled with Mo2TiC2Tx MXene for exceptionally high catalytic activity toward water oxidation

Progress in acidic water splitting has remained limited because of low oxygen evolution reaction (OER) activities, sluggish reaction kinetics, and severe catalyst degradation. Thus, a highly active and durable OER catalyst is required for the commercialization of acidic water electrolyzers. Here, we report t-phase ruthenium oxide atomic layers implanted on Mo2TiC2Tx MXene (RAL-M) as a model electrocatalyst for the OER in acidic media, which exhibits a remarkable mass activity (6.2 A mg−1), excellent turnover frequency (TOF; 2.4 s−1), and negligible loss of durability after 22 h in a two-electrode cell configuration. The mass activity and TOF of RAL-M are 150 times (RuO2-Premetek Co.) and 540 times (RuO2-Sigma-Aldrich) greater than the industrially adopted electrocatalysts at pH 0.48. Computational calculations show that the ruthenium active sites of RAL-M have a strong affinity to oxygen species (e.g., OH*, O*, and OOH*), which efficiently adapts water dissociation and favors both the adsorbate evolution and lattice oxygen mechanistic pathways to accelerate the OER. [Display omitted] •A novel t-phase ruthenium oxide atomic layers implanted on Mo2TiC2Tx MXene (RAL-M) was prepared.•For the first time, we reported RAL-M as a model electrocatalyst for the oxygen evolution reaction (OER) in acidic media.•The mass activity and turnover frequency of RAL-M was150/540 times greater than the industrial catalysts.•DFT reveals that the AEM and LOM pathways not only reduce the OER overpotential but also enhance the mass activity.