Bilayer MXene-Derived Carbon-Encapsulated Palladium Nanocatalysts: Engineering Robust Electronic and Chemical Interfaces for Oxygen Reduction and Zinc–Air Batteries

Designing highly active and durable electrocatalysts remain an ongoing challenge in the oxygen reduction reaction (ORR). Here, the reductive IL/Ti 3 C 2 T x (FA) is produced in a water-free mixture of formic acid (FA), ionic liquid (IL) and LiF, subsequently, the simultaneous reduction encapsulation trap the Pd nanocatalysts and IL within bilayer carbide-derived carbon (CDC) to obtain Pd@IL/CDC(FA) with high metal loading up to 69.7%. Thereby, the featured active phases in Pd@IL/CDC(FA) impart potent chemical nanoconfinement to defend metals from dissolution and aggregation, boost mass and electron transfer, and mediate oxidation states and adsorption/desorption of metal Pd in the ORR. Instead of deactivation and Ostwald ripening, the catalytic performances of Pd@IL/CDC(FA) are gradually enhanced in an accelerated durability test up to 20 000 cycles. In a Zn–air battery, the Pd@IL/CDC(FA) cathode gives a specific capacity of 812.6 mAh g Zn −1 and a voltage loss of only 41 mV in galvanostatic discharge for 1000 h. The work opens new venues in controllably preparing high activity and durable electrocatalysts from in-situ generated CDCs.