High-performance single-atom Ni catalyst loaded graphyne for H2O2 green synthesis in aqueous media

Abstract

The electrochemical synthesis of hydrogen peroxide (H₂O₂) provides a greener and more efficient method compared with classic catalysts containing toxic metals. Herein, we used first-principles density functional theory (DFT) calculations to investigate 174 different single-atom catalysts with graphyne substrates, and conducted a three-step screening strategy to identify the optimal noble metal-free single atom catalyst. It is found that a single Ni atom loaded on γ-graphyne with carbon vacancies (Ni@V-γ-GY) displayed remarkable thermodynamic stability, excellent selectivity, and high activity with an ultralow overpotential of 0.03 V. Furthermore, based on ab-initio molecular dynamic and DFT calculations under the H₂O solvent, it was revealed that the catalytic performance for H₂O₂ synthesis in aqueous phase was much better than that in gas phase condition, shedding light on the hydrogen bond network being beneficial to accelerate the transfer of protons for H₂O₂ synthesis.

Keywords: Aqueous phase; Density functional theory; Electrocatalysis; Graphyne; H(2)O(2) synthesis; Single-atom catalysts.