Covalent Immobilization of Black Phosphorus Quantum Dots on MXene for Enhanced Electrocatalytic Nitrogen Reduction

The electrochemical nitrogen reduction reaction (NRR) offers an environmentally benign and sustainable alternative for NH3 synthesis. Black phosphorus (BP) has a similar valence electron structure to nitrogen, which enables the effective adsorption and activation of N2 molecules for NRR. BP quantum dots (QDs) have larger specific surface areas and more abundant active centers than BP nanosheets. However, the aggregation and poor conductivity of BPQDs limit their catalytic activity. To solve these problems, we reported the synthesis of BPQDs/Ti3C2 heterostructures which is stabilized by interfacial P–O–Ti bonds. A new low-temperature electrochemical exfoliation method is used to prepare the BPQDs, in order to induce moderate oxygen-containing functional groups on the BPQD surface without damaging the basic structure of BP. The BPQDs/Ti3C2 heterostructures exhibit much enhanced NRR activity compared with pure BPQDs or Ti3C2 electrocatalysts, attributed to the strong interfacial coupling effect. The BPQDs/Ti3C2 could exhibit a high NH3 yield of 51.6 μg h–1 mgcat.–1, a Faradaic efficiency of 16.1%, and good durability.