N-doped graphitic carbon materials hybridized with transition metals (compounds) for hydrogen evolution reaction: Understanding the synergistic effect from atomistic level

TL;DR

This paper investigates nitrogen-doped graphitic carbon combined with transition metals at the atomic level, revealing how their electronic interactions enhance hydrogen evolution reaction catalysis, guiding the design of efficient electrocatalysts.

Contribution

It provides a systematic first-principles analysis of hybrid nitrogen-doped carbon and transition metal materials, elucidating the atomic-level mechanisms behind their catalytic activity.

Findings

Nitrogen doping activates the graphitic sheet for HER.

Optimal HER activity correlates with the C pz band center.

Electronic coupling strength influences catalytic performance.

Abstract

The hybrid nanostructures of nitrogen doped carbon materials and nonprecious transition metals are among the most promising electrocatalysts to replace noble metal catalysts for renewable energy applications. However, the fundamental principles governing the catalytic activity of such hybrid materials remain elusive. Herein, we systematically explore the electrocatalytic properties of transition metals, transition metal oxides and carbides substrates covered by nitrogen-doped graphitic sheets for hydrogen evolution reaction (HER). Our first-principles calculations show that the graphitic sheet is prominently activated by the nitrogen doping and the coordinate bond with metal (compound) substrate through intralayer and interlayer charge transfer. Such hybrid materials can provide optimal binding capability for HER catalysis with Tafel barrier down to 1.0 eV. The HER activity can be correlated to the C pz band center, which is in turn governed by the electronic coupling strength between the graphitic sheet and metal substrate, thus paving a way to rational design of graphitic carbon/transition metal hybrid electrocatalysts of high performance.