Carbon Dots Boost the Electrocatalytic Ammonia Oxidation Reaction on Pt2Pd Nanosheet

Abstract

The development of efficient catalysts for high-performance ammonia oxidation reaction (AOR) is crucial for direct ammonia fuel cells. However, AOR is severely affected by slow kinetics and the toxicity of reaction intermediates, which reduce the durability of precious metal catalysts. Here, a two-dimensional carbon dots modified Pt₂Pd nanoporous alloy (Pt₂Pd-CDs) is synthesized through the borane morpholine reduction of a platinum palladium oxide nanosheet. The Pt₂Pd_3 % CDs (the mass of CDs is 3 % of Pt₂Pd) exhibits high AOR activity and stability in alkaline media, with an onset potential of 0.41 V vs. RHE, which is 170 mV lower than that of the commercial Pt/C (0.58 V vs. RHE). In addition, after 2000 cycles of accelerated durability testing, the peak mass activity (115.3 A g_PGM⁻¹) decreases by only 25.8 %. This enhancement is mainly attributed to the unique advantage of two-dimensional nanoporous structure with a high electrochemical surface area, and the strong ammonia adsorption and the electron deliver capacity of CDs.