Two-dimensional PdPS: A multifunctional electrocatalyst towards HER, ORR, and supercapacitor applications

Two-dimensional (2D) materials have shown great promise in various energy conversion and storage applications due to their unique properties such as high surface area, mechanical flexibility, and tunable electronic properties. The development of efficient 2D materials for renewable energy generation and storage is currently a critical priority for meeting future energy demands. In this report, a novel, ternary 2D palladium phosphosulfide (PdPS) is synthesized upon the liquid exfoliation method and explored for energy conversion and storage applications. The surface morphology, crystallinity, and elemental composition of the as-synthesized materials have been thoroughly analyzed. The 2D-PdPS nanosheets show significantly improved electrocatalytic activity towards HER with a notably low onset potential (-0.12 V vs. RHE), and low Tafel slopes (90 mV dec⁻¹). Further, the same material is explored as an ORR catalyst to reduce oxygen in an alkaline medium. Moreover, the 2D PdPS can efficiently store the electrical charge with enhanced volumetric capacitance (3.38 mFcm⁻²) and better cyclic performances (∼100 % of the initial current after 1000 cycles). The simple exfoliation process for pristine PdPS opens possibilities for wide applications of a few layers of ternary phosphochalcogenide nanosheets in the fields of energy conversion and storage.