2-Dimensional nanosheets derived from graphitic carbon doped copper oxide@nickel oxide composite for electrochemical properties of CO2 and HER application

Abstract

The advancement of renewable energy storage and conversion technology with enhanced performance is driven by the continuously rising need for energy supplies. A novel approach to developing highly effective electrocatalysts that combine the advantageous features of carbon materials doped with the electrocatalytic characteristics of metal oxides for electrochemical properties of CO₂ and HER applications. In this work, we have synthesized a graphitic carbon nitride (GCN) by a thermal calcination method and copper oxide (CuO), and a novel composite nanosheet-like structure of graphitic carbon nitrate doped with copper oxide@nickel oxide (G/Cu/Ni) was synthesized via a co-precipitation method. The synthesized material was characterized by XRD, FTIR, UV, EDAX, FESEM, BET, TGA, and TEM. Additionally, adding the CuO and NiO changes the materials intrinsic conductivity and morphology structure, which creates a defect that causes enormous oxygen vacancies in the G/Cu and G/Cu/Ni composite. Consequently, G/Cu/Ni composites, electrocatalysts have outstanding intrinsic electrocatalytic ability on both HER and CO₂ in alkaline electrolytes due to the combined effect of metal oxides with carbon material enhancing their electrochemical activity. The GCN, CuO, G/Cu, and G/Cu/Ni composites exhibit a overpotential of 420 mV, 321, 296, and 257 mV, and the Tafel slope demonstrates approximate values of 305 mV dec⁻¹, 228, 172, and 121 mV dec⁻¹ with a current density of 10 mA cm⁻². Also, the CV curve showed that the Cdl values of GCN, CuO, G/Cu, and G/Cu/Ni displayed were 15 mF cm⁻², 17.5, 14.5 and 25 mF cm⁻² respectively. These outcome values suggest that the G/Cu/Ni composite is favorable for electrocatalytic application due to its huge surface area, narrow band gap, high electrical conductivity, and tunable nanosheet surface morphology, which improve the electrochemical properties, and the developed composite material is highly favorable for H₂ production in commercial industrial applications.