Emerging MXene-based electrocatalysts for efficient nitrate reduction to ammonia: recent advance, challenges, and prospects

Abstract

Ammonia (NH3) plays an irreplaceable role in traditional agriculture and emerging renewable energy. Its preparation in industry mainly relies on the energy-intensive Haber-Bosch process, which is associated with high energy consumption and large CO2 emissions. Recently, the nitrate reduction reaction (NO3-RR) driven by renewable energy has received extensive attention. This reaction can efficiently synthesize NH3 with water as a hydrogen source and NO3- as a nitrogen source under mild conditions, which is conducive to reducing energy consumption and promoting the carbon cycle. It is well known that the properties of electrocatalysts determine the performance of NO3-RR. As an emerging two-dimensional material, MXenes (transition metal carbides/nitrides/carbon nitrides) possess excellent electrical conductivity, large specific surface area and controllable surface functional groups, which shows great application potential in the field of NO3-RR. Herein, this review summarized the structure, properties and synthesis strategies of MXenes to elucidate the possibilities from foundation to application. Then, the latest research progress in applying MXene-based electrocatalysts to NO3-RR was summarized and the applicability of different NH3 detection methods was analyzed. Finally, the present challenges and future prospects of NO3-RR were presented. This review aimed to provide thoughtful insights into the rational design of MXene-based electrocatalysts for sustainable NH3 synthesis.

Atomic Layer Engineering of Pd Nanosheets for an Enhanced Hydrogen Evolution Reaction

“…The development of active and energy-efficient heterogeneous catalysts is a key issue in energy and environmental technology, and metal-based catalysts always play pivotal roles in catalyst research . Generally, the performance of heterogeneous catalysts largely depends on their morphologies and compositions. , Current research has focused on two-dimensional (2D) nanosheets, and 2D metal nanosheets (metallenes) are emerging for catalytic applications due to their unique structural and physicochemical properties. − Metallenes possess high surface area with undercoordinated metal atoms, which are favorable for enhanced activity owing to the high utilization of active sites. Thus, metallenes can reduce the usage of precious metals by improving the atom utilization and intrinsic activity.…”