Transition-Metal Borides (MBenes) as New High-Efficiency Catalysts for Nitric Oxide Electroreduction to Ammonia by a High-Throughput Approach.

Abstract

Here, the authors performed density functional theory calculations to study the catalytic performance of the nitric oxide reduction reaction (NORR) via a series of transition metal borides (MBenes). This work screened the M2 B2 type MBenes from the IVB to V transition metals from the periodic table and systematically probed the catalytic activity and selectivity for the NORR process. It has been reported that Fe2 B2 , Mn2 B2 , and Rh2 B2 can be high-performance catalysts for converting NO to NH3 with smaller limiting potentials than other MBenes, and Nb2 B2 and Hf2 B2 have low limiting potentials of -0.11 V and -0.17 V for the NO production of NH3 . The binding energy of ΔG*N can be a good descriptor of catalytic performance and is determined by the volcano plot of the rate-determining step. The reaction mechanisms for NO reduction to NH3 , N2 , and N2 O have been studied in detail, atomic *N can interact with another *N or one *NO molecule to form N2 and N2 O via two successive hydrogenations. In this regard, *NO hydrogenation to *NOH has a lower formation energy than *HNO, and the MBenes have high selectivity for promoting the NORR and suppressing the hydrogen evolution reaction competition process.