I have a research about synthesis nanomaterial adsorbent and i'm about to published in particular journal. but, i'm confused to looking cheaper one and be indexed by scopus. i'm about have financial problem.
All normal scientific journals offer free of charge publishing. There are only taxes if you want to publish color graph on hard-copy (which I never choose, because everybody uses the pdf-s, which appear in color) or if you want to keep your copy-right and let the paper appear in open access. All other journals that ask for additional fees or are open access only are quite suspicious and are usually not indexed in Scopus or Web of Science. So, I do not recommend you to publish in such journals.
Of course, publishing in a good journal depends also on the quality of your research and whether the topic matches the journal's scope.
A good journal would be the Journal of Nanoparticle Research (Springer) or others that you can find on Scopus.