You may see a synthetic route of Nb-NPs from the Nb2O5 precursor.

https://www.azonano.com/article.aspx?ArticleID=3297

You need to get the niobium in a form that it's in solution and then add a reducing agent sufficient to precipitate a Nb colloid (as it's the metal you want). This is not a sol gel process as it would be for say TiO2 (via the metal alkoxide)

My guess route would be to dissolve the niobium oxide in hydrochloric acid and reduce with 5 - 10% hydrazine hydrate solution. In industry the reduction is usually in the molten state but hydrogen is also stated to be able to carry out this reduction process.

I am unsure why the routes to niobium oxide are so highly recommended by the viewers of this post. The question asked about the production of niobium nanoparticles and not the oxide....

Starting with Nb lumps or µm powder (commercialy available), make Nb hydrides by reacting with hydrogen under 10-15 bars (activation could need 200°C repetively depending on the quality of surface). Then ball-mill a long time enough (5-10 hours the NbHx) so you will get nano NbHx, that could be desorbed under high vacuum at T > 300°C. Be carefull these powders will be rather pyrophoric (glove box manipulation).

Thanks all of you, it's very supportable discussion,

Niobium oxide can be dissolved using HF acid, forming Niobium Fluoride, than you can use in solution to produce nanoparticles.

@Gustavo

Are you seriously advocating a route using HF? You haven’t explained how to get niobium nanoparticles from the fluorides (which are hard to reduce).

Alan F Rawle yes.

I used this before, did the digestion of the sample using HF route and microwave, than with the dissolved NbF5 I could obtain Nb2O5 nanoparticles, you can use Pechini method. Particle size ranging between 10 to 100 nm, depending on the calcination temperature.

Further reading: https://www.ajol.info/index.php/sajc/article/download/123732/113287

Gustavo Henrique de Magalhães Gomes

I go back to an earlier post - the question asks for the production of niobium not niobium oxide.

Alan F Rawle my mistake.

But, there is some ways you may try. Like doing a solid state reaction using Nb2O5 powder with some amount of Nb in a reduction atmosphere (H2/Ar), but it is not guaranteed that you will obtain 100% of Nb NP's, it could contain a phase mixture.

Mudassar Nazir Gustavo Henrique de Magalhães Gomes

The production of niobium powder (not nano for reasons that are obvious to anyone skilled in the art) is not an easy procedure. See, for example:

Article Production of Nb-powder by magnesiothermic reduction of niob...

Article New Process for Niobium Powder Production

Even manufacturers of Nb powder (see: https://www.americanelements.com/niobium-powder-7440-03-1) provide little particle size or SSA information. I see from a Google search (from the manufacturer quoted above) that: 'Nanoscale Niobium Particles are typically 10-20 nanometers (nm) with specific surface area (SSA) in the 30 - 60 m2/g range and also available with an average particle size of 80 nm range with a specific surface area of approximately 12 m2/g.' This is not easy to find the same quote on the website or more information as to how these supposed values were measured (my suspicion is BET for SSA and SEM for 'particle size). The stated SSA's are not in theoretical agreement with the stated particle sizes as the powders are certain to be in aggregated form. Note: D[3,2] = 6/SSA

It is probably easiest to buy such a powder rather than attempt a synthesis.

One may be able to get a reasonably high SSA powder by means discussed in the above papers. Even manufacturers of Nb powder (see: https://www.americanelements.com/niobium-powder-7440-03-1) provide little particle size or SSA information.

The only 'guarantee' for nanoscale would be some colloidal sol preparation and Nb salts are extremely hard to reduce to the metal.

I think that the we need to hear from the originator of the question as to why Nb and not the oxide is required. Could be a simple misunderstanding.

Hey Alan F Rawle I completely agree with you that the author asked for a Niobium nano particle, so we should answer him about reducing the cationic niobium (i doubt that he has niobium oxide (NbO), as it is not that easy to obtain this oxide, and is not as famous as niobium pentoxide.. this reference "Niobium oxides and niobates physical properties: Review and prospects" makes it clear)...

However, i think that people are answering him how to obtain the oxides, because he asked for a sol-gel process, I've never seen a route leading to a metalic gel..

Luiz Fernando de Sousa Lima

I agree with you. Sol-gel methods are devoted to the oxides. This is why, in my original responses, I was looking at routes to produce a metal sol from reduction of appropriate Nb salts in solution, but it seems that this activation energy is too high for conventional reducing agents that produce Pd, Pt, Au, Ag and similar sols.

Atomizing Nb metal gives transient Nb metal nanoparticles but these combine together to form aggregates and agglomerates once the particles are brought in contact. I would look at BET for the initial characterization of 'nano' rejecting anything that was not > 60 m2/cm3.

The most frustrating part is that we've not heard from the poster of the question since Dec 18 2018. It may be that the oxide was the real or proper goal at that time and the poster can now state this. His interaction with RG is extremely patchy and looking at other questions and answers he has posed then many months appear to go by.

I consider it rude and impertinent to post a question and not follow up on responses or requests for clarification. I am removing him from the list of people I'll respond to.