Hydrothermal synthesized delafossite CuGaO2 as an electrocatalyst for water oxidation

Abstract

Hydrogen production from water splitting provides an effective method to alleviate the ever-growing global energy crisis. In this work, delafossite CuGaO2 (CGO) crystal was synthesized through hydrothermal routes with Cu(NO3)2·3H2O and Ga(NO3)3·xH2O used as reactants. The addition of cetyltrimethylammonium bromide (CTAB) was found to play an important role in modifying the morphology of CuGaO2 (CGO-CTAB). With the addition of CTAB, the morphology of CGO-CTAB samples changed from irregular flake to typical hexagonal sheet microstructure, with an average size of 1–2 μm and a thickness of around 100 nm. Furthermore, the electrocatalytic activity of CGO-CTAB crystals for oxygen evolution reaction (OER) was also studied and compared with that of CGO crystals. CGO-CTAB samples exhibited better activity than CGO. An overpotential of 391.5 mV was shown to be able to generate a current density of 10 mA/cm2. The as-prepared samples also demonstrate good stability for water oxidation and relatively fast OER kinetics with a Tafel slope of 56.4 mV/dec. This work highlights the significant role of modification of CTAB surfactants in preparing CGO related crystals, and the introduction of CTAB was found to help to improve their electrocatalytic activity for OER. Graphical abstract

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

“…24 Our group has previously studied the effect of surfactants on the preparation of ABO 2 , such as the hydrothermal synthesis of CuGaO 2 and CuCoO 2 . 13,18,25 Generally, the morphology and size of the catalyst could be controlled using surfactant-assisted hydrothermal methods. For example, the addition of 5 mmol of cetyltrimethylammonium bromide (CTAB) leads to a more homogeneous particle morphology and particle size of CuGaO 2 , and the crystal size was about 1-2 µm.…”

“…For example, the addition of 5 mmol of cetyltrimethylammonium bromide (CTAB) leads to a more homogeneous particle morphology and particle size of CuGaO 2 , and the crystal size was about 1-2 µm. 25 The addition of polyvinylpyrrolidone (PVP) could decrease the size of CuCoO 2 , and the size of CuCoO 2 decreased to 400 nm when 30 mmol of PVP was added. 13 Moreover, the size of CuCoO 2 was further decreased to 313 nm by adding 30 mmol of PVP and a Ga 2+ dopant.…”

CuGaO2/TiO2 heterostructure nanosheets: Synthesis, enhanced photocatalytic performance, and underlying mechanism

“…22 In the practical application of photocatalysis, in order to better utilize 2D nanomaterials to construct heterostructures to promote the separation and transport of photogenerated electron-hole pairs, rational selection of photocatalytic materials to design heterostructure structures is the focus of research. As a member of delafossite ABO 2 compound family, CuGaO 2 has excellent performance in the field of optoelectronic functional materials; it has a fundamental band gap of ∼2.0 eV and high carrier mobility, 26,27 which means that it is an emerging visiblelight-driven photocatalyst. 28 The unique quasi-2D layered superlattice structure of CuGaO 2 makes it widely studied in the design of 2D layered structures.…”

Hydrothermal preparation of oxide (Ga2O3, ZnO, TiO2) and derivative nanoparticles

“…Many oxide-based electrocatalysts, including Ga 2 O 3 nanostructures have been used for water splitting and removal of volatile organic compounds [8][9][10]. Apart from that, Ga 2 O 3 nanostructures have been demonstrated in applications such as gas sensors, solar cells, photodetectors and other optoelectronic applications due to their wide bandgap energy and good luminescence properties [11][12][13].…”

“…TiO 2 requires high processing temperature to achieve highly crystalline layers. In spite of that, TiO 2 is an important material for applications in solar cells, ultra-thin capacitors, optical devices, gas and chemical sensors, biomedical and self-cleaning coatings, and photocatalysis [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Apart from that, TiO 2 is widely used as pigment in paints, printing inks, cosmetics, papers, plastics, rubber etc.…”