Fabricating Black-Phosphorus/Iron-Tetraphosphide Heterostructure via a Solid-Phase Solution-Precipitation Method for High-Performance Nitrogen Reduction.

Although constructing heterostructures is considered as one of the most successful strategies to improve the activity of a catalyst, the heterostructures usually suffer from the cumbersome preparation treatments and low-yield. Inspired by a solid-phase solution-precipitation (SPSP) process, an approach for interface intensive heterostructures with high yield is developed. Herein, a black-phosphorus/iron-tetraphosphide (BP/FeP₄ ) heterostructure is prepared mechanochemically with high transient pressure by the solid-phase ball milling approach. The BP/FeP₄ heterostructure delivers excellent catalytic performance in the nitrogen reduction reaction (NRR) as exemplified by an NH₃ yield of 77.6 µg h^-1 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:msubsup><mml:mtext>mg</mml:mtext> <mml:mrow><mml:mtext>cat</mml:mtext> <mml:mi>.</mml:mi></mml:mrow> <mml:mrow><mml:mo>-</mml:mo> <mml:mn>1</mml:mn></mml:mrow> </mml:msubsup> </mml:mrow> <mml:annotation>\[{\rm{mg}}_{{\rm{cat}}{\rm{.}}}^{{\bm{ - }}1}\]</mml:annotation></mml:semantics> </mml:math> and Faradic efficiency of 62.9% (-0.2 V), which are superior to that of most NRR catalysts recently reported. Experimental investigation and density-functional theory calculation indicate the importance of excess phosphorus in the heterostructures on the NRR activity, which assists the Fe atom to activate N₂ via adsorbing the H atom. The results demonstrate the great potential of this new type of heterostructures prepared by the SPSP approach. Benefiting from the simple preparation process and low cost, the heterostructures offer a new insight into the development of highly efficient catalysts.