Hydrogenated Molybdenum Oxide Overlayers Formed on Mo Nitride Nanosheets in Ambient-Pressure CO₂/H₂ Gases

Abstract

Transition metal nitrides (TMN x ) often exhibit high catalytic activity in many important reactions. Due to their low stability in a reaction environment, it remains as a crucial issue to reveal surface active structures in catalytic reactions, particularly for the cases containing both oxidative and reductive gases. Herein, MoN and Mo2N nanosheets have been constructed on Al2O3(0001) and Au foil surfaces, and in situ surface characterizations are performed on the model catalysts in ambient-pressure CO2, H2, and CO2 + H2 gases. In situ Raman spectroscopy and quasi in situ X-ray photoelectron spectroscopy (XPS) analysis indicate that MoO3 and defective MoO3–x overlayers form on both MoN and Mo2N surfaces in CO2, and the surface oxidation occurs under a milder condition on Mo2N than on MoN. Further, a hydrogenated Mo oxide (H z MoO3–y ) overlayer forms in a CO2 + H2 atmosphere, as confirmed using quasi in situ XPS and time-of-flight secondary ion mass spectroscopy. The surface analysis over the model nitride catalysts suggests that O and/or H atoms may be incorporated into surface layers to form the active structure in many O and H-containing reactions.

Photothermal-coupled solar photocatalytic CO2reduction with high efficiency and selectivity on a MoO3−x@ZnIn2S4core–shell S-scheme heterojunction

“…O–Mo), adsorbed oxygen (O ads ) and H 2 O. 47 The survey spectra of the ZnIn 2 S 4 , MoO 3− x and MO@ZIS-3 samples are presented in Fig. 2a.…”

“…46 In the core-level spectrum of O 1s (Fig. S3c †), it can be divided into three peaks, which are ascribed to lattice oxygen 47 The survey spectra of the ZnIn 2 S 4 , MoO 3−x and MO@ZIS-3 samples are presented in Fig. 2a.…”

Operando Spectroscopy Observation of Mo Clusters‐Ti3C2TX Catalyst/Support Interface's Dynamic Evolution in Hydrogen Evolution Reaction

“…From Figure 4a-c, it can be seen that with increasing applied potential increases, two weak peaks appear at 418 and 612 cm −1 , which are attributed to the lattice vibration of the Mo-O bond. [33][34][35][36][37] This also indicates that the surface Mo is reduced in situ during the HER process. Further evidence is that the Mo 2+ signal is enhanced after the XPS reaction (Figure 4d).…”

First-Principles Simulations of H2O Dissociation at the Interfacial Region Formed by a Molybdenum Oxide Cluster and a Reduced MoO3–x Surface

“…Orthorhombic α-MoO 3 , the most stable crystal phase of molybdenum trioxide, is a versatile oxide compound with a wide range of applications in electronics, catalysis, − and sensors, , to name a few. It is susceptible to reduction, and along with the appearance of oxygen vacancies, the valence state of the Mo ions changes from +6 to +5 or even to +4 .…”