Gram-scale solvothermal synthesis of Fe-doped CuCoO₂ nanosheets and improvement of the oxygen evolution reaction performance

Abstract

In this work, we used Cu-BTC-IPA and Co(NO3)2·6H2O as precursors to synthesize CuCoO2 (CCO) nanocrystals with suitable crystal phase, morphology and high yield by changing the process parameters, such as...

Investigation of polyethylene glycol (PEG) assisted solvothermal synthesis of CuCoO2 nanosheets for efficient oxygen evolution reaction

“…10 The lattice oxygen ratio of CCO2 (48.89%) was higher than that of CCO1 (37.16%), which may be caused by the lattice distortion of CCO2. 20 According to the lattice oxygen oxidation mechanism, if the redox reactivity of O L is activated and participates in the OER, then the OER activity of this catalyst will be increased. 44,45 In summary, the decreased size of CuCoO 2 could contribute to the O L production without altering the surface composition and the valence states of the Cu and Co elements.…”

“…So, the Ni@CCO2 electrode had the fastest OER kinetics. The required overpotential to reach the benchmarked current density of 10 mA cm −2 and the Tafel slope of the Ni@CCO2 electrode were better than or close to the non-precious metal oxide catalysts reported in the literature (Table S2, ESI†), such as delafossite oxide, including CuCoO 2 ( η 10 = 390 mV, Tafel slope = 70 mV dec −1 ), 13 Ni doped CuCoO 2 ( η 10 = 409 mV, Tafel slope = 98 mV dec −1 ), 19 Fe doped CuCoO 2 ( η 10 = 369 mV, Tafel slope = 69 mV dec −1 ), 20 Ca doped CuCoO 2 ( η 10 = 470 mV, Tafel slope = 96.5 mV dec −1 ), 18 CuGaO 2 ( η 10 = 400 mV, Tafel slope = 61 mV dec −1 ); 25 or other perovskite oxide electrocatalysts, including LaFeO 3 ( η 10 = 420 mV, Tafel slope = 62 mV dec −1 ), 43 La 0.9 Sn 0.1 NiO 3− δ ( η 10 = 318 mV, Tafel slope = 74 mV dec −1 ), 47 La 1− x Sr x CoO 3− δ ( η 10 = 326 mV, Tafel slope = 70.8 mV dec −1 ), 48 and LaNiO 3 ( η 10 = 460 mV, Tafel slope = 96 mV dec −1 ). 49…”

“…11 Deng et al prepared micron sized CuScO 2 by a hydrothermal method, which required an overpotential of 490 mV at 10 mA cm −2 ( η 10 = 490 mV) and was capable of supporting galvanostatic OER electrolysis for 18 h. 12 Moreover, our group has been committed to the preparation and modification of CuCoO 2 used as an OER electrocatalyst since 2018. 13–20 We have prepared CuCoO 2 nanocrystals using a hydrothermal method by regulating reaction conditions, surfactants and reaction precursors. 13–16 Among them, the CuCoO 2 derived from MOF-based precursors (ZIF-67 and Cu-BTC) exhibits an excellent OER performance, which only needs a low overpotential of 364.7 mV to reach 10 mA cm −2 ( η 10 = 364.7 mV).…”

“…In addition, we have successfully doped different types of metals (such as Ca, Fe and Ni) into CuCoO 2 using a simple hydrothermal method. 17–20 In detail, a sample of 3 at% Fe-doped CuCoO 2 nanosheet has an ultrathin thickness of 15 nm and exhibits excellent OER activity ( η 10 = 369 mV). Furthermore, after continuous OER electrolysis for 18 h, the required overpotential exhibits a negligible increase of about 30 mV.…”

The interaction of carbon nanotubes (CNTs) with CuCoO2 nanosheets promotes structural modification and enhances their OER performance

“…To address these issues, our research group has focused on modifying CuCoO 2 nanocrystals and enhancing their OER performance. 8–16 By the utilization of metal–organic framework (MOF) materials such as Cu-BTC and ZIF-67 in the hydrothermal reaction precursors, we have successfully increased the specific surface area of CuCoO 2 nanocrystals, resulting in an exceptional OER performance (with a low overpotential of 364.7 mV at 10 mA cm −2 , i.e. , η 10 = 364.7 mV).…”