Exploring the Sub-nanoscale Structure of Cobalt Molybdenum Sulfide and the Role of a Cobalt Promoter in Catalytic Hydrogen Evolution.

Cobalt-promoted molybdenum sulfide (CoMoS) is known as a promising catalyst for H evolution reaction and hydrogen desulfurization reaction. This material exhibits superior catalytic activity as compared to its pristine molybdenum sulfide counterpart. However, revealing the actual structure of cobalt-promoted molybdenum sulfide as well as the plausible contribution of a cobalt promoter is still challenging, especially when the material has an amorphous nature.

Crystallization Pathways and Evolution of Morphologies and Structural Defects of α-MnO under Air Annealing.

Manganese dioxide nanomaterials have wide applications in many areas from catalysis and Li-ion batteries to gas sensing. Understanding the crystallization pathways, morphologies, and formation of defects in their structure is particularly important but still a challenging issue. Herein, we employed an arsenal of X-ray diffraction (XRD), scanning electron microscopy (SEM), neutron diffraction, positron annihilation spectroscopies, and calculations to investigate the evolution of the morphology and structure of α-MnO nanomaterials prepared via reduction of KMnO solution with CHOH prior to being annealed in air at 200-600 °C.