Efficient Electrochemical Water Splitting Through Self‐Supported Copper Selenide Nanosheets on Cu Foil: Effect of Immersion Time

Abstract

Transition metal selenides have been attracting enormous attention for electrocatalytic water oxidation. Herein, a self‐supported Cu3Se2@Cu electrocatalyst is prepared using the simple self‐growth method at different immersion times. The immersion time is critical in the conversion of Cu(OH)2 to Cu3Se2 as well as the modification of surface morphology. The growth of thin films is analyzed using a field emission scanning electron microscope and X‐ray photoelectron spectroscopy techniques. The electrochemical analysis shows that 230 and 351 mV of overpotential are required to reach a current density of 10 and 100 mA cm−2, respectively, for the oxygen evolution reaction (OER). The chronopotentiometry measurement over 50 h at a current density of 100 mA cm−2 shows excellent stability of the self‐grown electrocatalyst. This work may provide an effective and controlled strategy to convert Cu substrate to Cu3Se2 for efficient OER catalysts with the self‐growth method.

Bifunctional Electrocatalysts for Overall and Hybrid Water Splitting

“…Consequently, the CuSe couple exhibited excellent OWS under 1.0 M KOH (Figure g). Another example involves the work of Lokhande and coworkers, who prepared self-supported copper selenide electrocatalysts using a self-growth method with varying immersion times (Figure h) . SEM images (Figure i–l) illustrated the morphological transformation at different time intervals (1, 2, 4, and 6 h).…”

“…Another example involves the work of Lokhande and coworkers, who prepared self-supported copper selenide electrocatalysts using a self-growth method with varying immersion times (Figure 47h). 492 SEM images (Figure 47i− l) illustrated the morphological transformation at different time intervals (1, 2, 4, and 6 h). Initially, the surface of copper selenide with an immersion time of 1h (CS1) was composed of vertically aligned sheets of Cu(OH) 2 and Cu 2 Se, displaying large cage-like structures.…”

“…SEM images of (i) CS1, (j) CS2, (k) CS3, and (l) CS4. Reproduced with permission from ref . Copyright 2023 John Wiley and Sons.…”

Transition Metals‐Based Water Splitting Electrocatalysts on Copper‐Based Substrates: The Integral Role of Morphological Properties

“…For instance, recently Malavekar et al. reported copper selenide nanosheets on copper foil via simple self‐growth method [9] . The different morphologies of copper selenide was achieved by varying the immersion time of the substrate in the solution as shown in Figure 3.…”