You will be shown an abstract from a materials science research paper. Your task is to extract all synthesis operations described in the abstract into a structured JSON format. Your output should be a JSON array. Each entry in the array should be a JSON object describing a single synthesis operation. This object should have the following fields:

- "trigger": A verbal predicate indicating a synthesis operation. This should be a string extracted directly from the abstract.
- "arguments": An array of arguments specifying aspects of the synthesis operation. Each entry in the array should be a length-2 array formatted as [<argument_text>, <argument_type>]. The `argument_text` should be a string extracted directly from the abstract. The `argument_type` should be one of the following types: ["Recipe_Precursor", "Atmospheric_Material", "Participant_Material", "Recipe_Target", "Solvent_Material"].

For instance, suppose an excerpt from the abstract reads:

Tetraethoxysilane (TEOS, 98%) and cetyltrimethylammonium bromide (CTAB, 98%) were purchased from Fluka. The MTTZ-siloxy derivative (triethoxysilyl-propyl-5-mercapto-1-methyl-tetrazole) was synthesized as previously described [38].

This excerpt includes two operations, which could be annotated as follows.

[{"arguments": [["Tetraethoxysilane", "Recipe_Precursor"], ["cetyltrimethylammonium bromide", "Recipe_Precursor"]], "trigger": "purchased"}, {"arguments": [["MTTZ-siloxy derivative", "Recipe_Target"]], "trigger": "synthesized"}]

In your response, please include the JSON and no other text.

Abstract:
10.1016/j.energy.2014.08.058
Hierarchical 3D micro-/nano-V2O5 (vanadium pentoxide) spheres as cathode materials for high-energy and high-power lithium ion-batteries

Hierarchical 3D micro-/nano-V2O5 spheres were prepared via a facile low temperature hydrothermal method. Typically, NH4VO3 (ammonium metavanadate) solution, HCl, and poly (sodium 4-styrenesulfonate) (PSS, 2 mL) were well mixed in DI (deionized) water. The pH of the mixed solution was adjusted to be less than 2.7 so as to assist the growth of V2O5[58]. The resultant solution was transferred into a 100 mL Teflon-lined autoclave and heated to 180 degC for 24 h in an electrical oven. After cooling down naturally to room temperature, the precipitates were washed with DI water and ethanol alternatively for several times to remove residual starting materials before further characterization and electrochemical testing. As a reference, spherical V2O5 particles was also prepared by a PVP (polyvinylpyrrolidone)-assisted hydrolysis method [59].
[{"arguments": [["V2O5", "Recipe_Target"]], "trigger": "prepared"}, {"arguments": [["NH4VO3", "Recipe_Precursor"], ["poly (sodium 4-styrenesulfonate)", "Participant_Material"], ["water", "Solvent_Material"], ["HCl", "Participant_Material"]], "trigger": "mixed"}, {"arguments": [["solution", "Participant_Material"]], "trigger": "adjusted"}, {"arguments": [["solution", "Participant_Material"]], "trigger": "transferred"}, {"arguments": [["ethanol", "Solvent_Material"], ["precipitates", "Participant_Material"], ["water", "Solvent_Material"]], "trigger": "washed"}]