Rhodium

Zero-Valent Reaction:

Note! Use rhodium chloride hydrate!

Synthesis Setup:

Chemicals:

Rhodium (III) chloride hydrate, Stannous chloride, acetone

Procedure:

Stannous chloride (SnCl₂) is an excellent reducing agent and can be used to reduce many of the metal chlorides to a zero-valent species. The electrochemical redox potential favors oxidation of the tin halide and reduction of the metal halide.

Redox Potentials:	SnCl₂ → SnCl₄		-0.1375
	Rh²⁺ + 2e- → Rh(0)		0.758/td>
		Total:	0.8955

This reaction will favor formation of Rh(0) and SnCl₄ but just barely. Repeated intercalation reactions can get more in.

There is no need to prepare the glassware before intercalation. Setup the reflux apparatus as shown above. There is also no need to use an air-free setup. Prepare a stock solution of stannous chloride from 0.014 g of SnCl₂ in 5 mL.

Heat a solution of 0.01 g rhodium(III) chloride in 5 mL acetone in the round-bottom flask (Fig 1) to just below reflux (48°C). Once heated, drop the 2D material, free or suspended on a substrate, into the round bottom flask. Dropwise, add in the solution of tin(II) chloride very slowly over the course of 3 hours. Keep heating during this time at just below reflux. After 3 hours and complete injection of the stannous chloride solution, wait an additional 30 – 45 mins with heating. Afterwards, remove the substrate or 2D crystal from solution and rinse with acetone or ethanol several times. Rinsing with heated acetone (~45°C) will help remove any other salt impurities that may end up on the substrate.

How much can be intercalated into Bi₂Se₃ nanoribbons:

RhCl₃	SnCl₂	acetone	time	~ intercalated in Bi₂Se₃
0.01 g	0.014 g	10 mL	3.5 hours	2 atm % ± 1%

Relevant Publications:

M. Wang, D. Williams, G. Lahti, S. Teshima, D. Dominguez-Aguilar, K. J. Koski, Chemical intercalation of heavy metal, semimetal, and semiconductor atoms into 2D layered chalcogenides. 2D Materials, 5, 045005 (2018)

Supported by NSF DMR-1658019