Recent Trends and Perspectives in Electrochemical Water Splitting with an Emphasis on Sulfide, Selenide, and Phosphide Catalysts of Fe, Co, and Ni: A Review

Abstract

Increasing demand for finding eco-friendly and everlasting energy sources is now totally depending on fuel cell technology. Though it is an eco-friendly way of producing energy for the urgent requirements, it needs to be improved to make it cheaper and more eco-friendly. Although there are several types of fuel cells, the hydrogen (H2) and oxygen (O2) fuel cell is the one with zero carbon emission and water as the only byproduct. However, supplying fuels in the purest form (at least the H2) is essential to ensure higher life cycles and less decay in cell efficiency. The current large-scale H2 production is largely dependent on steam reforming of fossil fuels, which generates CO2 along with H2 and the source of which is going to be depleted. As an alternate, electrolysis of water has been given greater attention than the steam reforming. The reasons are as follows: the very high purity of the H2 produced, the abundant source, no need for high-temperature, high-pressure reactors, and so on. In earlier days, noble metals such as Pt (cathode) and Ir and Ru (anode) were used for this purpose. However, there are problems in employing these metals, as they are noble and expensive. In this review, we elaborate how the group VIII 3d metal sulfide, selenide, and phosphide nanomaterials have arisen as abundant and cheaper electrode materials (catalysts) beyond the oxides and hydroxides of the same. We also highlight the evaluation perspective of such electrocatalysts toward water electrolysis in detail.

Hollow TiO2@Co9S8 Core–Branch Arrays as Bifunctional Electrocatalysts for Efficient Oxygen/Hydrogen Production

“…One hand, the catalytic performance of powder Co 9 S 8 -based catalysts is greatly undermined because the active sites would be covered or annihilated during the preparation of test electrode with polymer binders. [28] Moreover, powder-form materials are prone to detach from the surface of test electrode at large working currents due to the bubble striking effect. This can greatly reduce life span and increase inner resistance.…”

Mixed Metal Sulfides for Electrochemical Energy Storage and Conversion

“…[1][2][3][4][5] Electrochemical energy storage and conversion systems with high comprehensive performance, such as lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), hybrid supercapacitors (HSCs), metal-air batteries (MABs), and water splitting, are very promising technologies for overcoming the worldwide energy challenge. [1][2][3][4][5][6][7][8][9][10][11][12][13] Among these technologies, LIBs, SIBs, HSCs, and MABs are all electrochemical energy storage systems, while water splitting is a typical electrochemical energy conversion system. www.advenergymat.de contact interfaces to make the overall reaction happen.…”

“…www.advenergymat.de contact interfaces to make the overall reaction happen. [6,7] Currently, precious metal-based electrocatalysts (Pt for HER and IrO 2 /RuO 2 for OER) are the most efficient electrocatalysts to reduce the overpotential. [6,7] Similar to MABs, the practical application of water splitting is commercially less viable because of the high cost and scarcity of precious metal-based electrocatalysts.…”

“…[6,7] Currently, precious metal-based electrocatalysts (Pt for HER and IrO 2 /RuO 2 for OER) are the most efficient electrocatalysts to reduce the overpotential. [6,7] Similar to MABs, the practical application of water splitting is commercially less viable because of the high cost and scarcity of precious metal-based electrocatalysts. Thus, it can be seen that the large-scale application of these electrochemical energy technologies is still hindered by their inferior electrochemical performances and high cost, which are largely determined by the properties of the electroactive materials.…”

Electrocatalytic activity of CoFe2O4 thin films prepared by AACVD towards the oxygen evolution reaction in alkaline media

“…The advantage of using AACVD to prepare thin films of electrocatalysts is that it requires no binders, hence undesirable effects such as stability failure or decrease in conductivity can be easily avoided [18]. CoFe 2 O 4 displays an overpotential of 490 mV at a current density of 10 mA cm − 2 in 1 M NaOH, and a Tafel slope of 54.2 mV dec − 1 .…”