Engineering vacancy and hydrophobicity of two-dimensional TaTe2 for efficient and stable electrocatalytic N2 reduction
Zhenqing Zhao, Jongseo Park, Changhyeok Choi, Song Hong, Xiangchao Hui, Hao Zhang, Tsz Woon Benedict Lo, Alex W. Robertson, Zengxiang Lv, Yousung Jung, Zhenyu Sun
Abstract
Demand for ammonia continues to increase to sustain the growing global population. The direct electrochemical N 2 reduction reaction (NRR) powered by renewable electricity offers a promising carbon-neutral and sustainable strategy for manufacturing NH 3 , yet achieving this remains a grand challenge. Here, we report a synergistic strategy to promote ambient NRR for ammonia production by tuning the Te vacancies (V Te ) and surface hydrophobicity of two-dimensional TaTe 2 nanosheets. Remarkable NH 3 faradic efficiency of up to 32.2% is attained at a mild overpotential, which is largely maintained even after 100 h of consecutive electrolysis. Isotopic labeling validates that the N atoms of formed NH 4 + originate from N 2 . In situ X-ray diffraction indicates preservation of the crystalline structure of TaTe 2 during NRR. Further density functional theory calculations reveal that the potential-determining step (PDS) is ∗NH 2 + (H + + e – ) → NH 3 on V Te -TaTe 2 compared with that of ∗ + N 2 + (H + + e – ) → ∗N–NH on TaTe 2 . We identify that the edge plane of TaTe 2 and V Te serve as the main active sites for NRR. The free energy change at PDS on V Te -TaTe 2 is comparable with the values at the top of the NRR volcano plots on various transition metal surfaces.