Facile Two‐Step Synthesis of Delafossite CuFeO₂ Photocathodes by Ultrasonic Spray Pyrolysis and Hybrid Microwave Annealing

Abstract

Delafossite CuFeO 2 photocathodes have recently attracted attention for water splitting due to their suitable band gap (1 .5 eV) and high stability in aqueous media. The preparation of CuFeO 2 usually requires long and energy-intense treatments in an inert atmosphere for the full conversion of spinel CuFe 2 O 4 to delafossite CuFeO 2 . Herein, we report the preparation and characterization of highly uniform and stable CuFeO 2 thin films obtained via a combination of inexpensive ultrasonic spray pyrolysis followed by a short hybrid microwave treatment (4 min). The resulting films show good stability in alkaline media and produce a photocurrent of~650 μA/cm 2 under 1.5 AM simulated sunlight and with oxygen bubbling. The effect of the rapid transformation from the spinel to the delafossite phase induced by hybrid microwave annealing was investigated with synchrotron-based X-ray absorption spectroscopy (XAS) and Xray photoelectron spectroscopy (XPS).[a] I.

Progress in Ternary Metal Oxides as Photocathodes for Water Splitting Cells: Optimization Strategies

“…[117] Many other reports have appeared in the last years pursuing both higher photoelectrochemical activity by using different synthetic routes and an in-depth understanding of the PEC performance of this material. [118][119][120][121][122][123][124] Despite the low photocurrents reported for water reduction, the material keeps on attracting interest owing to the Earth abundance of the constituent elements, narrow bandgap, high charge carrier mobility, and excellent stability in aqueous media under the typical conditions of applied potential and solution pH used in the experiments. [125] This has motivated the development of different strategies to overcome the barriers for water reduction, which will be commented in Section 3.…”

The Structural and Electrochemical Properties of CuCoO2 Crystalline Nanopowders and Thin Films: Conductivity Experimental Analysis and Insights from Density Functional Theory Calculations

“…Among various delafossite oxides, copper-based delafossite oxides stand out as promising candidates due to their desirable electrical and optical characteristics. The copper-based delafossite oxide, specifically CuMO 2 (where M represents Al, Ga, Fe, Co, Mg, Fe, Cr…), has attracted considerable attention for diverse applications such as batteries [ 9 , 10 , 11 , 12 , 13 , 14 , 15 ], luminescent materials [ 16 , 17 , 18 , 19 , 20 , 21 ], thermoelectrics [ 22 , 23 , 24 , 25 , 26 , 27 , 28 ], solar energy conversion and photocatalysis [ 29 , 30 , 31 , 32 , 33 , 34 , 35 ], hydrogen production through water splitting using photocathodes [ 36 , 37 , 38 , 39 , 40 , 41 ], and gas sensors [ 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ]. In this study, we focus on the CuCoO 2 compound, in view of intriguing structural, optical, and electrical properties; it has only been studied in a limited number of publications, and in most of them, the CuCoO 2 compound has shown interesting properties to be treated as a possible material in photovoltaic solar cells [ 50 ,…”

“…. ), has attracted considerable attention for diverse applications such as batteries [9][10][11][12][13][14][15], luminescent materials [16][17][18][19][20][21], thermoelectrics [22][23][24][25][26][27][28], solar energy conversion and photocatalysis [29][30][31][32][33][34][35], hydrogen production through water splitting using photocathodes [36][37][38][39][40][41], and gas sensors [42][43][44][45][46][47][48][49]. In this study, we focus on the CuCoO 2 compound, in view of intriguing structural, optical, and electrical properties; it has only been studied in a limited number of publications, and in most of them, the CuCoO 2 compound has shown interesting properties to be treated as a possible material in photovoltaic solar cells [50][51][52][53][54]…”

Effect of Deposition Parameters on Morphological and Compositional Characteristics of Electrodeposited CuFeO2 Film

“…CuFeO 2 thin film has been considered as a one-size-fits-all electrode in these application devices. It has been synthesized via various deposition techniques such as sputtering [2,[20][21][22], pulsed laser deposition [23][24][25], sol-gel based spin coating [1,26,27], hydrothermal method [19,28], electrodeposition [9,[29][30][31] and spray pyrolysis [3,32,33]. Among these deposition techniques, the electrodeposition is an advantageous method for fabrication of high-quality CuFeO 2 thin film.…”