Atomic-scale insights into the interfacial charge transfer in a NiO/CeO2 heterostructure for electrocatalytic hydrogen evolution

Cr-Doped CeO2 Nanocrystals Supported on Reduced Graphene Oxide Nanosheets for Electrocatalytic Hydrogen Evolution

“…The ΔG H* value, ideally approaching zero (ΔG H* ≈ 0), was a crucial indicator of catalyst activity, making it an optimal descriptor for catalysts. 40,53 To further elucidate these findings, Figure 5b,c presents the charge differential densities of Cr-CeO 2 and Cr 2 O 3 /CeO 2 . It was evident that in both Cr-CeO 2 and Cr 2 O 3 /CeO 2 structures, the Cr sites experienced a loss of electrons (indicated in pink color), with concurrent electron transfer from Cr to Ce.…”

“…39 In this setup, nickel foam electrodes coated with Cr-CeO 2 /rGO nanocomposites were utilized as the working electrode. 40 As shown in Figure 3a, the polarization curve obtained at a scanning speed of 20 mV s −1 is shown by the linear scanning voltammetry method. Among the tested samples, the 5CrCeG sample displayed a notably low overpotential of 83 mV at a current density of 10 mA cm −2 .…”

“…The electrocatalytic performance of representative samples for the hydrogen evolution reaction (HER) evaluated in an alkaline medium (1 M KOH) using a three-electrode system . In this setup, nickel foam electrodes coated with Cr-CeO 2 /rGO nanocomposites were utilized as the working electrode . As shown in Figure a, the polarization curve obtained at a scanning speed of 20 mV s –1 is shown by the linear scanning voltammetry method.…”

“…The ΔG H* value, ideally approaching zero (ΔG H* ≈ 0), was a crucial indicator of catalyst activity, making it an optimal descriptor for catalysts. 40,53 Figure 5a shows the calculated ΔG H* of the hydrogen adsorption on various models, including pure CeO S9. These results strongly indicated that Cr-CeO 2 facilitated more rapid electron transfer compared to CeO 2 and Cr 2 O 3 /CeO 2 .…”

“…These models served as the basis for assessing the Gibbs free energy (Δ G H* ) of hydrogen atom (H*) adsorption and desorption throughout the entire HER process. The Δ G H* value, ideally approaching zero (Δ G H* ≈ 0), was a crucial indicator of catalyst activity, making it an optimal descriptor for catalysts. , Figure a shows the calculated Δ G H* of the hydrogen adsorption on various models, including pure CeO 2 , Cr-CeO 2 , Cr 2 O 3 /CeO 2 , and pure Cr 2 O 3 , as displayed in Figure S8. Notably, Cr-CeO 2 presented the lowest Δ G H* of −0.174 eV, compared with Cr 2 O 3 /CeO 2 (−0.574 eV), CeO 2 (1.102 eV), and Cr 2 O 3 (−1.155 eV).…”