Sustainable synthesis of ammonium nickel molybdate for hydrodesulfurization of dibenzothiophene

This paper reports a sustainable,water-assisted,solid-state method for synthesizing ammonium nickel molybdate（（NH4）HNi2（OH）2（MoO4）2,ANM）,a precursor for an unsupported hydrodesulfurization（HDS） catalyst.The associated ANM formation mechanism is also discussed.The synthesis route consists of physical mixing of the raw materials,water-assisted grinding and heating.The formation mechanism involves replacement of a Mo atom by a Ni atom,generating the metastable intermediate（NH4）4（NiH6Mo6O（24））·5H2O.Heating of this intermediate at 120 ℃ removes the added water and produces ANM.Catalysts prepared by this method exhibit almost the same physicochemical properties and catalytic performance during the HDS of dibenzothiophene as materials made from ANM synthesized by a chemical precipitation procedure.Compared with traditional hydrothermal or chemical precipitation methods,this water-assisted,solid-state synthesis provides several significant advantages,including simplifying the synthetic procedure,reducing waste and energy costs and increasing product yields.These features will be highly important with regard to allowing the application of ANM in industrial-scale processes involving HDS reactions.This water-assisted,solid-state strategy can also be extended to the synthesis of isomorphous compounds such as ammonium cobalt（zinc and copper） molybdate.

聚乙二醇对非负载型Ni-Mo催化剂结构及加氢脱硫性能的影响

非负载型加氢催化剂由于金属含量高,因而具有较高的加氢活性。然而目前采用水热法合成获得的金属活性相之间容易产生聚集而降低其分散度,从而影响其活性的发挥。本文采用非离子型的水溶性聚合物聚乙二醇(PEG)作为助剂来增加非负载型催化剂的分散性,考察了聚乙二醇对催化剂晶形结构、孔结构和表面形貌等性质的影响,并以二苯并噻吩(DBT)和催化裂化(FCC)柴油为原料对催化剂活性进行了评价。结果表明,加入聚乙二醇后,其非负载型催化剂晶粒间形成许多囊泡结构,金属分散度大有提高;同时催化剂颗粒表面疏松多孔,增加了可暴露活性位数量。活性评价结果表明,PEG的加入可明显提高非负载型Ni-Mo催化剂的加氢脱硫活性。