When High-Temperature Cesium Chemistry Meets Self-Templating: Metal Acetates as Building Blocks of Unusual Highly Porous Carbons

Abstract

Self-templating is a facile strategy for synthesizing porous carbons by direct pyrolysis of organic metal salts. However, the method typically suffers from low yields (<4%) and limited specific surface areas (SSA<2000 m² g^-1 ) originating from low activity of metal cations (e.g., K⁺ or Na⁺ ) in promoting construction and activation of carbon frameworks. Here we use cesium acetate as the only precursor of oxo-carbons with large SSA of the order of 3000 m² g^-1 , pore volume approaching 2 cm³ g^-1 , tunable oxygen contents, and yields of up to 15 %. We unravel the role of Cs⁺ as an efficient promoter of framework formation, templating and etching agent, while acetates act as carbon/oxygen sources of carbonaceous frameworks. The oxo-carbons show record-high CO₂ uptake of 8.71 mmol g^-1 and an ultimate specific capacitance of 313 F g^-1 in the supercapacitor. This study helps to understand and rationally tailor the materials design by a still rare organic solid-state chemistry.

Keywords: CO2 Adsorption; Cesium Acetate; Cesium Effect; Porous Carbons; Supercapacitor.