Enhancing Electrocatalytic Water Splitting Activities via Photothermal Effect over Bifunctional Nickel/Reduced Graphene Oxide Nanosheets

Abstract

Electrocatalytic water splitting has huge potential for generating hydrogen fuel. Its wide application suffers from high energy loss and sluggish reaction kinetics. The adoption of appropriate electrocatalysts is capable of reducing the overpotential and accelerating the reaction. Present research mainly focuses on adjusting electrocatalysts, but the performances are also dependent on other parameters. Therefore, the development of an efficient strategy to enhance electrocatalytic performance through integrating with other driving force, especially a renewable driving force, is of great interest. Herein, we present a photothermal-effect-driven strategy to promote the electrocatalytic hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities of nickel/reduced graphene oxide (denoted as Ni/RGO) bifunctional electrocatalysts. The Ni/RGO composite exhibited significant enhancement of activities after exposure to light irradiation (49 mV and 50 mV decrease of overpotential at 10 mA/cm2 for HER and OER, respectively). It was found that the improved electrocatalytic activities arose from the photothermal effect of Ni/RGO, which can efficiently facilitate the thermodynamics and kinetics of electrocatalytic reactions. Furthermore, the photothermal-effect-induced enhancement for electrocatalysis showed good stability, indicating its promising potential in practical application.

3D Graphene‐Based H2‐Production Photocatalyst and Electrocatalyst

“…[ 17–19 ] Thus, so far, various materials were adopted to be hybridized with 2D graphene and used as the multifunctional catalysts for photocatalytic and electrocatalytic HER. [ 20–25 ] However, there are still some challenges for the dispersion of the powder catalysts during synthesis and reaction processes. Due to the existing strong van der Waals force and π–π interaction, the graphene sheets tend to stack or aggregate together.…”

“…Given its excellent electrical conductivity and large specific surface area, 2D graphene can be employed as an attractive and valuable support/substrate for catalyst confinement, which not only prevents the catalyst from aggregating but also exposes more active sites for the catalytic reaction 17–19. Thus, so far, various materials were adopted to be hybridized with 2D graphene and used as the multifunctional catalysts for photocatalytic and electrocatalytic HER 20–25. However, there are still some challenges for the dispersion of the powder catalysts during synthesis and reaction processes.…”

Multifunctional Nickel Sulfide Nanosheet Arrays for Solar‐Intensified Oxygen Evolution Reaction

“…[ 19,20 ] The photothermal materials with high light‐to‐heat conversion efficiency, however, have been rarely integrated into the electrochemical system to enhance the electrocatalytic performance, and only the coupling of additional carbon‐based photothermal material, such as reduced graphene oxide (RGO) and carbon hemispheres, with electrocatalytically active component is an exception. [ 21–23 ] The introduction of the additional photothermal materials increases the complexity of the electrocatalytic system. Moreover, the spatial inconsistency between the photothermal component and electrocatalytic component will lessen the localized temperature enhancement at electrode surface, and thus the promotion effect on the electrocatalytic reactions.…”

High photoresponse and fast carrier mobility: Two‐dimensional rGO‐AgBr/Ag composite based on Z‐scheme heterointerface with plasma for hydrogen evolution

“…For the limited storage capacity of traditional fossil petroleum energy, it is impossible to support our long-term consumption. [10][11][12][13][14][15][16] Therefore, the development of more efficient approaches for hydrogen energy has been attracting extensive attention of many scholars. 1,2 Currently, several new energy sources were developed, such as wind power generation, 3 ocean energy, 4 biomass energy, 5 natural gas 6 and so on.…”

“…[7][8][9] However, hydrogen energy is mainly prepared by traditional electrolysis method with high cost and low efficiency, so that it is hard to meet our practical application requirement. [10][11][12][13][14][15][16] Therefore, the development of more efficient approaches for hydrogen energy has been attracting extensive attention of many scholars. Fujishima and Honda proposed to use titanium dioxide photoelectrode to catalyze water splitting under light in 1972, then photocatalytic technology has attracted more attentions and been widely studied for its advantages of low cost and no pollution.…”