Pd-Based Metal-Support Heterostructure Catalyst for High Performance Electrocatalytic N2 Reduction Reaction

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Electrocatalytic nitrogen (N2) reduction reaction (eNRR) is of great interest to produce the green ammonia (NH3). However, the competitive side reaction of hydrogen (H2) evolution reaction (HER) and slow proton-couple electron transfer (PCET) step still become a bottleneck where resulting in poor N2 selectivity and yield of NH3 production. The heterostructures of metal and boron nitride (BN) analogs have been computatively demonstrated and suggested as a potential eNRR catalyst to improve eNRR performance as both suppressing HER and accelerating PCET step. However, experimental demonstration is still challenging due to the complex synthetic method required to achieve a uniform and dense distribution of metal catalysts on the BN surface. Here, we present the facile and uniform formation of the Pd nanoparticles (NPs) on defective boron nitride (BN) using ultrafast radiative Joule-heating within short time (~0.5 s), which is the first-time demonstration on the BN family. Especially, thanks to the strong electronic metal-to-support interaction (EMSI) effect between the defect site of BN surface and Pd NPs, the electron-deficient state of Pd NPs facilitates the significant reduce of free energy during the PCET step which is beneficial to interact with N2 molecules. In particular, we observe that Pd NPs on defective BN support exhibit the high NH3 selectivity of 68% in the neutral aqueous electrolyte and 59% of NH3 selectivity and 53.3 µg/h/cm2 of NH3 yield rate in the acidic media, respectively, which are the highest values of the selectivity and NH3 yield rate among existing Pd-based eNRR catalysts.