Doping carbons beyond nitrogen: an overview of advanced heteroatom doped carbons with boron, sulphur and phosphorus for energy applications

TLDR

Heteroatom‑doped carbons are widely used in energy devices, and while nitrogen doping has advanced significantly, recent interest has focused on boron, sulfur, and phosphorus, whose differing electronic properties can create synergistic effects and show promise as electrocatalysts. This review updates the latest developments in advanced heteroatom doping of carbon beyond nitrogen. Because boron, sulfur, and phosphorus are larger and less electronegative than carbon, they induce structural distortions and altered charge densities that influence the performance of doped carbons in energy applications.

Abstract

Heteroatom doped carbon materials represent one of the most prominent families of materials that are used in energy related applications, such as fuel cells, batteries, hydrogen storage or supercapacitors. While doping carbons with nitrogen atoms has experienced great progress throughout the past decades and yielded promising material concepts, also other doping candidates have gained the researchers' interest in the last few years. Boron is already relatively widely studied, and as its electronic situation is contrary to the one of nitrogen, codoping carbons with both heteroatoms can probably create synergistic effects. Sulphur and phosphorus have just recently entered the world of carbon synthesis, but already the first studies published prove their potential, especially as electrocatalysts in the cathodic compartment of fuel cells. Due to their size and their electronegativity being lower than those of carbon, structural distortions and changes of the charge densities are induced in the carbon materials. This article is to give a state of the art update on the most recent developments concerning the advanced heteroatom doping of carbon that goes beyond nitrogen. Doped carbon materials and their applications in energy devices are discussed with respect to their boron-, sulphur- and phosphorus-doping.