Quantum mechanics

Gibbs free energy

Catalysis

Valence (chemistry)

Chemical physics

Reactivity (psychology)

Electrochemistry

Materials science

Graphene

Density functional theory

Transition metal

Electronic structure

Antibonding molecular orbital

Molecule

Atomic orbital

Physical chemistry

Alternative medicine

Thermodynamics

Hydrogen

Physics

Nanotechnology

Organic chemistry

HOMO/LUMO

Computational chemistry

Medicine

Chemistry

Electrode

Electron

Pathology

Advanced Energy Materials

The proper choice of nonprecious transition metals as single atom catalysts (SACs) remains unclear for designing highly efficient electrocatalysts for hydrogen evolution reaction (HER). Herein, reported is an activity correlation with catalysts, electronic structure, in order to clarify the origin of reactivity for a series of transition metals supported on nitrogen-doped graphene as SACs for HER by a combination of density functional theory calculations and electrochemical measurements. Only few of the transition metals (e.g., Co, Cr, Fe, Rh, and V) as SACs show good catalytic activity toward HER as their Gibbs free energies are varied between the range of –0.20 to 0.30 eV but among which Co-SAC exhibits the highest electrochemical activity at 0.13 eV. Electronic structure studies show that the energy states of active valence dz2 orbitals and their resulting antibonding state determine the catalytic activity for HER. The fact that the antibonding state orbital is neither completely empty nor fully filled in the case of Co-SAC is the main reason for its ideal hydrogen adsorption energy. Moreover, the electrochemical measurement shows that Co-SAC exhibits a superior hydrogen evolution activity over Ni-SAC and W-SAC, confirming the theoretical calculation. This systematic study gives a fundamental understanding about the design of highly efficient SACs for HER.

Rational Design of Graphene-Supported Single Atom Catalysts for Hydrogen Evolution Reaction