Co3O4 for sustainable CO2 reduction and possible fine-tuning towards selective CO production

Coproduction of Glyceric Acid and Glycolic Acid from Biomass-Based Sugars over a Ru/Co3O4 Catalyst

“…The X-ray diffraction (XRD) patterns (Figure a) of Co 3 O 4 displayed peaks at 2θ = 19.0, 31.2, 36.8, 38.6, 44.8, 55.7, 59.3, and 65.2°, which were attributed to the (111), (200), (311), (220), (400), (422), (511), (440) planes of cubic Co 3 O 4 (JCPDS 42–1467), respectively. − When 3 wt % Ru was loaded, the XRD patterns of Ru/Co 3 O 4 showed no obvious change, indicating that Ru loading did not change the structure of Co 3 O 4 . However, no obvious signals assigned to Ru were observed in the XRD patterns of Ru/Co 3 O 4 , possibly due to the high dispersion of Ru loading .…”

“…The transmission electron microscopy (TEM) image of Ru/Co 3 O 4 further confirmed the high dispersion of Ru with an average particle size of ∼1 nm (Figure c). High resolution TEM (HRTEM) images (Figure d) of Ru/Co 3 O 4 showed Ru 0 (002) with an interplanar spacing of 0.214 nm and RuO 2 (101) with an interplanar spacing of 0.254 nm, − suggesting the coexistence of Ru 0 and RuO 2 . The SAED images (Figure S2) also showed the crystal planes of Ru 0 (002), Ru 0 (102), RuO 2 (110), and RuO 2 (101). , …”

“…The RuO 2 and RuO n /2 contents were 47.6 and 27.1%, respectively, while the Ru 0 content was calculated to be 25.3%, possibly derived from the decomposition of the RuCl 3 ·3H 2 O precursor. , This demonstrated that Ru n + (4 ≤ n ≤ 6) was the major Ru species in the Ru/Co 3 O 4 catalyst. The Co 2p spectra could be deconvoluted to four peaks at 795.8–796.5, 793.5–794.5, 780.7–781.5, and 778.9–779.5 eV, assigning to Co 2+ (2p 3/2 ), Co 3+ (2p 3/2 ), Co 2+ (2p 1/2 ), and Co 3+ (2p 1/2 ), respectively. − Ru/Co 3 O 4 showed a higher Co 2+ /Co 3+ ratio (0.83 vs 0.63, Table S4) than Co 3 O 4 . The Fourier-transform infrared (FT-IR) spectra (Figure b) of Ru/Co 3 O 4 and Co 3 O 4 showed two main peaks at 666 and 570 cm –1 , which were assigned to the vibrations of Co 2+ –O in the tetrahedral sites and Co 3+ –O in the octahedral sites in the spinel structure of Co 3 O 4 , respectively .…”

“…Given the increase in the Co 2+ /Co 3+ ratio after Ru loading, the oxygen species in Ru/Co 3 O 4 were then characterized. The O 1s spectra in the XPS pattern of Ru/Co 3 O 4 could be deconvoluted into three peaks located at 529.1–529.8, 530.5–531.5, and 532.2–532.9 eV, assigning to O I (lattice oxygen), O II (oxygen species chemically adsorbed on oxygen vacancies), and O III (surface-adsorbed oxygen species), respectively. − Compared to Co 3 O 4 , Ru/Co 3 O 4 showed a higher O II content (oxygen species chemically adsorbed on oxygen vacancies). It was assumed that the Ru loading induced an increase of the oxygen vacancies (Table S4).…”

Electrocatalytic and Selective Oxidation of Glycerol to Formate on 2D 3d-Metal Phosphate Nanosheets and Carbon-Negative Hydrogen Generation

“…The double-layer capacitance (C dl ) was determined from cyclic voltammetry (CV) curves recorded within a potential range, where no Faradaic current was observed. Various scan rates (10,20,40,60, and 80 mV/s) were utilized, and plotting the cathodic charging currents against these rates allowed the determination of the C dl slope. The ECSA was determined using the following equation.…”