Synthesis strategies towards amorphous porous carbons with selective oxygen functionalization for the application as reference material

Manipulation of carbon surface functionalization and especially of oxygen surface groups has been demonstrated to be key for obtaining high performance materials in a multitude of applications. Although control of carbon surface chemistry offers large potential in many technical relevant applications, qualitative and quantitative analysis of surface oxides for amorphous and porous carbons remains challenging. In this study, we attempt selective, organic chemistry-based functionalization of a polymer-derived porous model carbon featuring high oxygen loadings, with the aim to establish analytical standards for temperature programmed desorption (TPD) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). In this context, quantitative chemical reduction of an oxidized carbon material with lithium aluminum hydride (LiAlH4) is utilized as the key for the synthesis of carbon materials with defined ensembles of oxygen surface groups (hydroxyl groups and ethers). Based on this reduction strategy, selective LiAlH4 reduction based on protection group chemistry leads to aldehydes, ketones and quinones as surface functional groups and chemical grafting is studied for the selective introduction of phenyl esters, methyl ethers and carboxylic acids. All materials are evaluated with respect to the applicability as analytical standard by DRIFT spectroscopy, TPD, X-ray photoelectron spectroscopy and titration methods. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Manipulation of carbon surface functionalization, especially oxygen surface groups, is crucial for high-performance materials. This study focuses on selective organic chemistry-based functionalization of polymer-derived porous carbon with high oxygen loadings to establish analytical standards. Different types of oxygen surface groups are successfully introduced by chemical reduction and protection group chemistry, and their chemical properties on the material surface are studied. Evaluation of all materials using various analytical methods provides a basis for their use as analytical standards.