Redispersion of Mo-Based Catalysts and the Rational Design of Super Small-Sized Metallic Mo Species

Abstract

Supported metal nanoparticle catalysts are one of the most important classes of heterogeneous catalysts but suffer from agglomeration in many cases. Particle redispersion is of great importance for restoring the activity. We report this phenomenon happening at Mo catalysts, in which small-sized Mo species can be achieved from the original large-sized Mo oxide on a carbon support (carbon cloth) in H2 atmosphere. Detailed characterizations of the specific process were done with ex situ and in situ techniques. Additionally, the small-sized Mo species expose a large number of active sites, which exhibit a high Faradaic efficiency (FE) in the electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions. Our discovery of the formation process of small-sized Mo species gives more deep understanding of the redispersion phenomenon and provides potential application in industry.

Recent Advances in Noble‐Metal‐Free Catalysts for Electrocatalytic Synthesis of Ammonia under Ambient Conditions

“…[34] After that, Chen et al presented the process of forming smallsized Mo catalysts. [35] The small-sized Mo species provided a large number of active sites and reached a high FE of 22.3% in NRR. In addition, molybdenum oxides, nitrides, carbides, and sulfides are also utilized in NRR reactions.…”

“…After that, Chen et al. presented the process of forming small‐sized Mo catalysts . The small‐sized Mo species provided a large number of active sites and reached a high FE of 22.3% in NRR.…”

Ultra-fine platinum species supported on niobium pentoxide for CO oxidation

“…13 Original largesized Mo oxide on carbon support was calcined in an H 2 atmosphere for obtaining small-sized Mo species. 16 Aer vacuum calcination and H 2 reduction, thermal treatment of 0.2 wt% Pt/SiO 2 was used to synthesize Pt particles less than 1 nm that are uniformly dispersed on the SiO 2 . 17 At present, some researchers on the evolution of single-atom catalysts (SACs) during activation and catalytic reactions show that ultrane cluster is more active than pure single atoms.…”

Selective Electrochemical Reduction of Nitrogen to Ammonia by Adjusting the Three-Phase Interface

“…Substantial efforts have been dedicated to optimization of the NRR selectivity by developing various heterogeneous electrocatalysts including metals, metal oxides, and nonmetallic materials, particularly focused on tailoring the particle size, crystallinity, morphology, defect density, and surface active sites [15–28]. For example, single-atom catalysts were demonstrated to have an atomic ensemble effect on suppressing the HER since it was perceived that only the top site of single-atom catalysts with positive relative energies contributed to H adsorption, with respect to the multiple adsorption sites (top, bridge, and hollow) for bulk metal surfaces [29].…”