Tetrabutylammonium chloride monohydrate, a quaternary ammonium cation, is a catalyst in a chemical reaction[1].
References
[1] Iris Burgers, et al. The Effect of Salts on the CO2 Reduction Product Distribution in an Aprotic Electrolyte. Chemphyschem. 2024 Dec 16;25(24):e202400589. DOI:10.1002/cphc.202400589