Is it always necessary to remove a metal nanoparticle stabilizer before catalysis?

• Ru and Ir nanoparticles were stabilized by PVP and deposited on alumina.
• The effect of calcination–reduction treatments was studied.
• For efficient ring opening catalysis, complete stabilizer removal is not necessary.
• For CO chemisorption, complete stabilizer removal is mandatory.

The answer is no. It depends on the catalyzed reaction and the active metal. For Ru and Ir nanoparticles stabilized by polyvinylpyrrolidone (PVP), their activities in an indan ring opening are not affected by the residual polymer, while CO chemisorption requires complete polymer removal. The in situ cleaning effect of the reaction atmosphere was found negligible. The findings are supported by TEM, XPS, CHN analysis, indan- and CO-TPD, CO chemisorption analyses and catalytic measurement. The necessity for complete polymer removal must be evaluated on a case-by-case basis; in some cases mild catalyst pretreatment is enough.

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