Tuning electronic structure of PdZn nanocatalyst via acid-etching strategy for highly selective and stable electrolytic nitrogen fixation under ambient conditions

A delicate hybrid catalyst with defective PdZn NPs anchored on an N-doped hollow carbon polyhedrons fabricated by a facile acid-etching achieves a notable selectivity to NH3 with a high FE of 16.9 % due to its locally induced electronic-rich feature. [Display omitted] •Rich defects are created via acid-etching on PdZn NPs loaded on N-doped hollow carbon polyhedrons.•The etched-PdZn/NHCP catalyst exhibits a Faradaic efficiency up to 16.9 % for NH3 synthesis.•The etched-PdZn/NHCP catalyst is practically stable for electrolysis of 50 h in 0.1 M PBS. Although ambient nitrogen fixation powered by renewable electricity is emerging as a highly attractive alternative to the classical Haber–Bosch process, it still remains extremely challenging. In this work, a facile acid-etching strategy was employed to synthesize defect-rich PdZn nanoparticles (NPs) supported on N-doped hollow carbon polyhedrons (etched-PdZn/NHCP), which could serve as an attractive and efficient electrocatalyst for the nitrogen reduction reaction (NRR). The synthesized etched-PdZn/NHCP electrocatalyst achieved higher NH3 yields (5.28 μg mg−1cat. h−1) than pristine PdZn NPs in a phosphate buffer solution. Remarkably, the existence of abundant defects in the etched PdZn NPs favored N2 adsorption and activation, resulting in significantly high Faradaic efficiency (FE) of 16.9 % towards NH3 and outperforming previously reported Pd-based NRR electrocatalysts. Furthermore, the etched-PdZn/NHCP cathode exhibited good long-term electrochemical durability with both the NH3 production and the FE remaining practically stable after 50 h of electrolysis.