Atomically dispersed Pt single sites and nanoengineered structural defects enable a high electrocatalytic activity and durability for hydrogen evolution reaction and overall urea electrolysis

Abstract

The scarcity and high cost of PGM electrocatalysts are the key bottleneck in the mass-scale commercialization of many electrolysis technologies. Bifunctional single-atom electrocatalysts (SACs) are promising alternatives for PGM electrocatalysts in next-generation electrolysis technologies because of their superior intrinsic activity and perfect atom utilization. Regulating the coordination environment of platinum atomic sites identifies their electrocatalytic performance. Therefore, exploring more appropriate supports could facilitate the construction of active and durable electrocatalysts with ultralow noble metal content. Herein, we report on a reliable approach for producing a novel type of SACs composed of atomically dispersed Pt active sites stabilized on defective NiCo layered double hydroxide (Pt/D-NiCo LDH) nanosheets as an ultralow-Pt hybrid electrocatalyst for hydrogen evolution reaction (HER), urea oxidation reaction (UOR), and full urea-water electrolysis. The optimized Pt1/D-NiCo LDH-24 SAC displays a remarkable HER and UOR performance where it yields a current density of 10 mA cm−2 at 37 mV and 1.25 V vs. RHE for HER and UOR, respectively. Symmetrical urea electrolyzer constructed of Pt1/D-NiCo LDH-24 electrodes attains 10 mA cm−2 at a cell voltage of 1.32 V vs. RHE, demonstrating superior activity and durability over 60 h operation when compared to commercial Pt/C(+)‖RuO2(−) system.