Three-dimensional reduced graphene oxide decorated with cobalt metaphosphate as high cost-efficiency electrocatalysts for the hydrogen evolution reaction

Abstract

The development of cost-effective non-noble metal electrocatalysts is critical for the research of renewable energy.

Electrochemical Co-reduction of N2 and CO2 to Urea Using Bi2S3 Nanorods Anchored to N-Doped Reduced Graphene Oxide

“…Raman spectroscopy was used to study the surface structure of RGO, N-RGO, Bi 2 S 3 , and Bi 2 S 3 /N-RGO electrocatalysts. As shown in Figure b, the Raman spectra of RGO, N-RGO, and Bi 2 S 3 /N-RGO electrocatalysts exhibit two characteristic peaks at 1340 and 1580 cm –1 , which correspond to the D (defect sp 3 carbon) and G (graphitic sp 2 carbon) bands, respectively, of graphene-based materials . Notably, the value of I D / I G is closely associated with the number of defect sites in graphene-based materials .…”

“…High-resolution C 1s XPS was performed to further study the different chemical states and surroundings of the RGO, N-RGO, and Bi 2 S 3 /N-RGO composites. The C 1s XPS spectra could be (Figure c) deconvoluted into five peaks: C–N defects (283.3 eV), , C–C (284.8 eV), C–N (285.9 eV), CO (287.6 eV), and O–CO (288.4 eV) . The C–C (284.8 eV) peak exhibits the strongest intensity among the five peaks, corresponding to sp 2 -hybridized carbon of RGO, and the C–N (285.9 eV) and O–CO (288.4 eV) peaks in the C 1s XPS spectrum are also consistent with the XPS peaks of RGO in the literature. , In the XPS spectra of N-RGO and Bi 2 S 3 /N-RGO composites, the signal at 285.9 eV is ascribed to the C–N bond, which originates from the addition of ammonia during the hydrothermal process .…”

“…The C 1s XPS spectra could be (Figure c) deconvoluted into five peaks: C–N defects (283.3 eV), , C–C (284.8 eV), C–N (285.9 eV), CO (287.6 eV), and O–CO (288.4 eV) . The C–C (284.8 eV) peak exhibits the strongest intensity among the five peaks, corresponding to sp 2 -hybridized carbon of RGO, and the C–N (285.9 eV) and O–CO (288.4 eV) peaks in the C 1s XPS spectrum are also consistent with the XPS peaks of RGO in the literature. , In the XPS spectra of N-RGO and Bi 2 S 3 /N-RGO composites, the signal at 285.9 eV is ascribed to the C–N bond, which originates from the addition of ammonia during the hydrothermal process . Additionally, the N 1s XPS spectrum exhibits peaks at 398.4, 399.7, and 400.8 eV (Figure S4b), corresponding to pyridinic-N, pyrrolic-N, and graphitic-N, respectively, further attributed to the formation of the C–N bond on N-RGO and Bi 2 S 3 /N-RGO composites .…”

“…As shown in Figure 1b, the Raman spectra of RGO, N-RGO, and Bi 2 S 3 /N-RGO electrocatalysts exhibit two characteristic peaks at 1340 and 1580 cm −1 , which correspond to the D (defect sp 3 carbon) and G (graphitic sp 2 carbon) bands, respectively, of graphene-based materials. 39 Notably, the value of I D /I G is closely associated with the number of defect sites in graphenebased materials. 24 The enlarged Raman spectra (Figure 1d) of Bi 2 S 3 /N-RGO, N-RGO, and RGO electrocatalysts exhibit I D / I G values of 1.11, 1.02, and 0.96, respectively, and the results were attributed to the increase in the number of defect sites on the surface of RGO samples because of the Bi 2 S 3 nanorods and doped N atoms.…”

“…The C 1s XPS spectra could be (Figure 3c) deconvoluted into five peaks: C−N defects (283.3 eV), 29,45 C−C (284.8 eV), 39 C−N (285.9 eV), 46 C�O (287.6 eV), 36 and O−C�O (288.4 eV). 37 The C−C (284.8 eV) peak exhibits the strongest intensity among the five peaks, corresponding to sp 2 -hybridized carbon of RGO, 39 and the C−N (285.9 eV) and O−C�O (288.4 eV) peaks in the C 1s XPS spectrum are also consistent with the XPS peaks of RGO in the literature. 37,46 In the XPS spectra of N-RGO and Bi 2 S 3 /N-RGO composites, the signal at 285.9 eV is ascribed to the C−N bond, which originates from the addition of ammonia during the hydrothermal process.…”