# Mechanistic Insights in Acceptorless Dehydrogenation of N‑Heterocycles Using Graphenes as Carbocatalysts

## TL;DR

This paper explores how graphene can act as a metal-free catalyst to release hydrogen from organic compounds, offering a sustainable energy solution.

## Contribution

The study reveals o-quinone groups on graphene as active sites for hydrogen release through a detailed mechanistic investigation.

## Key findings

- o-Quinone groups on graphene act as active sites for acceptorless dehydrogenation.
- Epoxide intermediates form during the catalytic cycle, leading to hydrogen release.
- The mechanism enables regeneration of o-quinone groups, completing the catalytic cycle.

## Abstract

Catalytic dehydrogenation
is a critical transformation
in the chemical
and energy sectors, particularly for reversible hydrogen storage systems.
One of the most promising systems for hydrogen storage is the development
of liquid organic hydrogen carriers (LOHCs), which have the potential
capacity of storing and releasing hydrogen gas on demand. Catalytic
direct dehydrogenation represents a greener, promising method to generate
hydrogen in situ from these hydrogen-dense carriers. The catalytic
activity of graphene materials as metal-free carbocatalysts in the
acceptorless dehydrogenation of N-heterocycles has been explored.
Herein, a detailed mechanistic investigation has been conducted through
both experimental (stoichiometric and masking experiments) and DFT
calculations on the reaction mechanism. The proposed mechanism identifies o-quinone groups as the active sites responsible for catalysis,
involving the transformation of o-quinone groups
into epoxide intermediates, which release molecular hydrogen and regenerate
the o-quinone groups, completing the catalytic cycle.
This work provides insight into the design of efficient metal-free
catalysts for their use in LOHCs storage systems, paving the way for
sustainable energy solutions.