Preparation of nanoporous flake molybdenum powder by sol-gel reduction method

Abstract

Due to the unique microstructure, nanoporous materials, have great potential application in the fields of catalysis, sensing and fabrication of advanced materials. This study mainly focuses on the thermal decomposition mechanism of ammonium paramolybdate and nanoporous flake molybdenum powder fabrication. The decomposition process was clarified and verified. The approximate molar formation enthalpy and some thermodynamic data of ammonium paramolybdate and its related decomposition products under experimental conditions were estimated by enthalpy change values of decomposition reaction in the various stages. Nanoporous flake molybdenum powder was fabricated by sol-gel reduction method at different pH values. The mechanism of transition from ammonium paramolybdate to molybdenum powder was elucidated. The results show that the morphology of products in each stage is hereditary. With the increase of pH value, the reaction was complete and the powder morphology gradually became flake and the shape distribution was uniform and distribution. When the pH is 5, through inert gas passivation treatment, the final molybdenum powder has a uniform particle size of about 65 nm and a specific surface area of about 7.5 m 2 /g. The nanoporous powder with such a special morphology and microstructure has potential prospects in the field of functional materials such as catalysis. • Heredity was found in the mechanism of AHM to Mo transformation. • CA can not only be used as complexing agent, but also control the pH value of the solution. • The morphology of MoO 3 and Mo particles gradually became flakes with the increase of pH value. • Inert gas passivation can reduce and concentrate the PSD and decrease agglomeration. • Nanoporous flaky Mo powder was prepared by sol-gel reduction method with high specific surface area.