In Situ Electrochemical Reconstitution of CF–CuO/CeO₂ for Efficient Active Species Generation

Abstract

Achievement of the intrinsic activity by in situ electrochemical reconstruction has been becoming a great challenge for designing a catalyst. Herein, an effective electrochemical strategy is proposed to reconstruct the surface of the CF–CuO/CeO2 precursor. Under the stimulation of oxidative/reductive potential, abundant active sites were successfully generated on the surface of CF–CuO/CeO2. Remarkably, the implantation of oxygen vacancy-rich CeO2 synergistically optimizes the chemical composition and electronic structure of CF–CuO/CeO2, greatly promoting the generation of active species. Systematic electrochemical experiments indicate that the superior catalytic performance of reconstructed CF–CuO/CeO2 could be attributed to CuOOH/CeO2 and Cu2O/Ce2O3 active species, respectively. The oxidative-/reductive-activated CF–CuO/CeO2 was further employed in a paired cell for the synergistic catalysis of hydroxymethylfurfural oxidation with 4-nitrophenol hydrogenation. As a result, nearly 100% Faraday efficiency for furandicarboxylic acid/4-aminophenol production was achieved in the paired system (−0.9 V vs Ag/AgCl, 1.5 h). Therefore, the electrochemical reconstruction via oxidative/reductive activation has been confirmed as a feasible approach to significantly excite the intrinsic activity of a catalyst.

Strengthening the Stability of the Reconstructed NiOOH Phase for 5-Hydroxymethylfurfural Oxidation

“…The crystal structures of Ni­(OH) 2 , CeO 2 , and 14%Ce-Ni­(OH) 2 were determined by XRD patterns. According to Figure S1a, four weak diffraction peaks at 28.5, 33.0, 45.9, and 56.3° correspond to the (111), (200), (220), and (311) planes of cubic CeO 2 (JCPDS 34-0394), respectively . In Figure S1b, three diffraction peaks at 23.3, 34.3, and 60.6° are well matched with the (101), (015), and (110) planes of Ni­(OH) 2 (JCPDS 38-0715) .…”

“…The peak intensity of the Ce 4+ species was significantly enhanced, whereas that of the Ce 3+ species decreased after activation, suggesting that the Ce 3+ species were converted into Ce 4+ species. Meanwhile, the O 1s spectrum of 14%Ce-Ni­(OH) 2 displays three peaks at 529.1, 530.7, and 532.0 eV (Figure d), belonging to the lattice oxygen (O L ), oxygen vacancy (O v ), and molecular oxygen (O c ), respectively . The obviously enhanced O L peak after activation could be attributed to the increase of the NiOOH species …”

Colloidal synthesis of hexagonal CuFe(SxSe1−x)2 nanoplates with exposed highly active (220) facets for boosting overall water splitting

“…The Raman peaks at 471 cm −1 and 558 cm −1 can be attributed to FeOOH and the Raman peaks at 1065 cm −1 show the presence of Cu 2 O species in the catalyst after the reaction. 54,55 The autoxidation may have positive effects on the OER activity in the following ways: firstly, the presence of amorphous Fe or Cu-based oxide/hydroxides may increase the catalytic activity and provide a protective barrier for the active sites. Secondly, the strong coupling interactions and synergistic effects between CuFe(S 0.8 Se 0.2 ) 2 and the corresponding oxide/hydroxides facilitate electron transfer in the OER process.…”

Enhanced Electrocatalytic Activity and Ultrasensitive Enzyme-Free Glucose Sensing Based on Heterogeneous Co(OH)2 Nanosheets/CuO Microcoral Arrays via Interface Engineering

“…47,48 We have performed XPS analysis for the Co(OH) 2 NSs/CuO MCAs after electrocatalytic oxidation for 0.2 mM glucose (Figure S10), while the extra XPS peaks of CuOOH and CoOOH were detected at 935.16/954.67 and 781.69/796.78 eV in Cu 2p and Co 2p spectra, respectively. 49,50 This indicated that the composite in alkaline medium could be electro-oxidized to double oxyhydroxides (CoOOH and CuOOH), which adsorbed glucose molecules and directly catalyzed them to gluconolactone under alkaline conditions. The process was briefly described by eqs 5−7 as follows: Furthermore, the electrochemically active surface area (ECSA) was also estimated by calculating the double layer capacitance (C dl , Figure S11).…”